The right way to fix it is to purchase a replacement socket from Nissan or the autoparts store.  They come with "Pig tail" wires to splice into the existing harness.  Cut the harness wires close to the old socket and splice to the appropriate wire on the new socket one at a time so you don't mix them up.  Use a "butt" or "blind" crimp connector (Click Image at Left), wire nuts or even twist them together and solder.  DON'T just twist the wires together and leave them. You'll be asking for trouble. 

The cheap way.  If the socket isn't too badly corroded you might be able to reuse the same socket.  This is what I did.  I cut the wires to the socket and removed it so I could work on it easier.  I took a dull X-acto knife and scraped the inside of the socket until I had clean shiny metal all around.  I also restored the two tin contacts at the bottom of the socket by resoldering them.  This is a little tricky because there is a spring in there.  Push down on the disk and support the wire from the back while you solder.  Otherwise the disk and spring will go flying one way and the wire will fall out the other way.  That's all they are anyway in the first place is solder beads so soldering works great.  Splice the socket back in to the right wires.  Before inserting the bulb into the socket, coat the bare metal on the inside of the socket with axle grease or silicone grease to prevent further corrosion.  This should then work just as well as a new socket.

Dead Tail Lights.  Here's a hot tip from Seth Herstad.  According to Seth, his tail lights had gone dead and couldn't find the problem until he looked at the tail light sensor, the 1x3 inch white plastic box on the right side tail light assembly (Click Image at Left). The tail light sensor gives you a warning light on the dash when one or more tail light bulbs have burned out.  It had detached from the tail light assembly and was hanging up-side-down.  Water from the leak at the top of his tail light ran down the wires and into the sensor.  His sensor was corroded and knocked out his tail lights.  Once he replaced the sensor the tail lights worked again.  Thanks Seth!

If the socket and lamp pins look good check the continuity of the lamp.  Using an ohm meter, the three pins should have under 1ohm  resistance in any combination (Click Image Above).  Obviously, if the lamp has no continuity in any one or more combinations it's bad.  If you don't have a meter, carefully jumper the lamp to a battery to check the high and low beams.  If the Lamp checks out ok, turn the head light switch on including the high beams and check for 12 volts dc at the socket.  Two pins should have 12vdc and one will be 0v (click the image to see it full size).  If you have an ohm meter check continuity of the 0 volt contact to chassis ground.  It should be 0 ohms. 

Now, if the lamp is good, there is 12vdc to the socket and good ground continuity, two things remain as the possible cause.  The switch in the steering wheel column or the "mechanical" contact between the socket and the lamp. Check the socket first since you are likely to have it out at this point. Commonly the female spade terminals in the socket loosens and makes contact intermittently.  Looking into the socket you can see the end of the spade terminal.  Also you can see a narrow space along side the terminal.  Slip a small screw driver down the space and pry against the connector to close the gap in it.  Don't close it all the way.  Close it enough to get a good tight grip on the lamps spade terminals.  This should restore the normal function of the intermittent head lamp. 

 If you still don't have 12vdc at the socket the only thing left is the steering column switch.  The switch doesn't cost a lot and I recommend replacing it.  You can also clean the contacts but this may or may not be a lasting fix.  It's your call.  You will need a steering wheel puller.  A cheap one will do.  Remove the horn fuse and then take off the rubber horn cover.  Loosen the large steering wheel nut and back it off one or two turns but don't take it off.  Set up the puller and start cranking away.  The puller will get quite tight before the wheel lets loose.  It will let go with a violent bang so be prepared!  Once it's loose, take the puller off and remove the nut.  Pull the wheel off and grab the washer as you do or it will slip inside the wheel assembly where it may be difficult to retrieve.  You should now see the headlight switch.  Clean it or replace it.  If this doesn't fix it the car's possessed.

The easiest thing to test is whether or not the cable is good.  The speed sensor is a round object mounted to the fender well near the battery with the speedometer cable and red, green, black and yellow wires attached to it (Click Image Above Left). You can test the sensor in the car or take it out and bench test it.  It's your call.  Remove the cable from the speed sensor first by unscrewing the locking ring.  As you pull it apart watch for a black plastic alignment ring.  Don't loose it.  Prop the cable up so you can observe the "Square" end of the cable.  Put the car in 5th gear and roll the car forwards or backwards 3 or 4 feet.  If the cable is good you should see it rotate a half a turn or so.  Check the speed sensor next. 

To test the speed sensor you will need small insulated alligator clips, a multimeter (preferably analog, digital is ok also) and a 5 or 6 volts DC source for bench testing (Click Image at Left).  You can use 12 volts from the car battery with a 750 ohm (680-820 will do) current limit resistor in series if the sensor is still in the car.  Do not use 12 volts directly!  The three wires from the sensor are as follows: BLACK=GROUND, RED=+12VDC, YELLOW=SIGNAL.  Attach the alligator clips to the three contacts in the connector ensuring the are not shorting together.  Connect the voltage source to the 2 outer clips, ground to black wire and +DC to the red wires.  Connect the multimeter negative to the black wire and positive to the yellow wire.  Set the multimeter to the 10 or 100K ohm range, which ever gives you the best resolution.  Slowly turn the shaft of the sensor.  If the sensor is good you will see the needle of the sensor swing back and forth.  If you are using a digital, the resistance should swing from about 200 ohms to over a meg or infinity.  If you have made your connections properly and you see no deflection in the meter, the sensor is likely to be dead.  Prepare a proper burial. 

This is one of the easiest fixes.  If the vertical bars of the torque/RPM gage are fully lit there is a break in the vacuum hose that runs from the right side if the manifold to the boost sensor.  The hose is attached to a fitting on the right side of the manifold at the mid point (Click Image Above Left).  This hose runs around the back of the engine and up to the boost sensor located in the left front corner of the engine compartment under the spark coil (Click Image at Left).  The hose connection is under the sensor where it can't be seen. You can squeeze your fingers down there and feel it.  This is where the hose commonly breaks.  Best thing to do is to replace the entire hose rather that just cutting it back.

This is a tough one to research.  Not just of the complexity of the electronics but because of the location and difficulty in removing/repairing/replacing.  Once I have a complete set of a digital dash and power unit I will be able to do my testing on the bench rather than half-in half-out of the car.  What I have is preliminary and only partial to the overall set of problems.  Two digital dash malfunctions have been identified so far.  These two are particular to the digital dash power unit which is nested under the dash on the drivers side. 

The first problem became evident when I removed the power unit but left all its two cables connected.  I wiggling the connectors and the dash flickered or went out all together.  Also some individual gages flickered or went out independent of others.  When I inspected the connectors and contacts I was surprised to find corrosion in the bottom of the connector body (Click Image at Left).  What I theorize, although have to prove yet, is that condensate from an air conditioning duct may have dripped into the connector.  The way the power unit is oriented the connector is at the top where any liquid dripping inside the dash can flow into the connector.  I was able to remove the corrosion by spraying the contacts with window cleaner and brushing with a very small wire brush.  Then rinsing with more window cleaner and blowing it dry with compressed air. 

Another problem I found, of which the symptoms are almost indistinguishable from the above problem, is broken and loose solder connections (Click Image at Left).  years of road vibration has weakened the solder connections until they have become intermittent or open all together.  Aside from the connector solder joints I also found several loose solder joints at two of the large power transistors.  This is easily remedied by resoldering the connections with a good rosin core solder and a 25 to 40 watt iron. 

Despite these problems found and corrected they did not remedy my intermittent fuel gage problem.  This leads me to believe that the problem is entirely in the digital dash itself.  I should be receiving several dashes in the next week or two to do some deeper exploration.  Stay tuned. 
 

Fix it now!  Remove the T tops.  In the corners of the T top wells near the door there are 4 drain tubes.  These are sealed to the sheet metal with body putty.  As the putty ages it shrinks, cracks and pulls away from the body (Click Image).  Clean the area well with a paper towel and window cleaner or alcohol.  Using a tube of silicone sealant, force the silicone deep into the crack and smooth it nice and level with your finger all around the drain.  DO NOT get any IN the drain tube.  Let the silicone set for a few hours before putting the T tops back on.  Next time it rains you should be pleased not to get a wet shoulder.

Removal Preparation.  First things first.  Go and purchase a roll of "Glass Setting Butyl Tape" made by PRO Adhesives and Sealants or an equivalent.  It is actually a "rope" rather than a tape which is 3/8ths diameter and 15 feet long and is plenty to do both windows.  Remove the rear plastic interior panel over the tail lights.  Also take off the vertical trim along the door if necessary.  To remove the right side panel I did not have to remove this trim as the door trim and window trim only overlap by an inch or so.  It was easy to slip it past.  I was not so lucky on the left side.  For some reason the left side was a much tighter fit.  I had to remove the door and T top trim.  Two screws hold the side panel.  Remove the garment hook and screw.  The other screw is at the far end of the window trim near the tail lights.  Pull the side panel out starting at the top and lay it on the cargo deck.  You won't be able to take it out if the car as the shoulder belt passes through it. 

Window removal. Loosen the 2 nuts holding the window in place (Click Image).  One forward and one back.  When you finally remove the nuts hold the window with one hand or have someone hold the window.  It's not likely to fall out but don't take chances.  SLOWLY push out the forward edge of the window, near the door, out  from the frame. The back corner of the outside window trim is held with a body fastener. Once the front edge is out slide the window back a 1/2 inch to unhook the fastener. If you break it don't panic. Most auto parts stores have a variety of replacements. The window is sealed with a black gummy Butyl rubber strip. It is the most unpleasant aspect of this. You don't have to remove all of it to reseal the window.  You will have to remove all traces of it if you use silicone to seal the window or the silicone won't adhere to the window and frame with any confidence. 

IMPORTANT NOTE: If you plan a total restoration, as I am, and expect to remove the window at a later date, don't seal it with silicone! You will have a terrible time getting the window out again as with silicone you are essentially "cementing" the window in place.  You may not get it out without breaking it at a later date.  Use Butyl tape if you plan on removing the window again. 

Installation Preparation.  Use a dull scraper or putty knife and remove as much of the old Butyl sealer as you can.  You can leave a thin film on both surfaces (Click Image At Left).  Clean around the frame and window with window cleaner to remove road dirt.  Apply the Butyl tape (Click Image Below Left) to the window frame, not to the window.  Press it on but don't crush it, leave it round in shape.  Also don't stretch it as it is applied. DO stretch a small piece of the Butyl rubber like taffy into a thin strip and wrap it around the window mounting studs and the body fastener to seal the 3 holes in the frame.  I also put some under the mounting nut washers for an added seal on the inside. 

Window Installation.  When you are ready to put the window in, slip the body fastener into the slot in the trailing end of the exterior trim.  Line up the fastener and 2 mounting studs and press the window onto the frame GENTLY and start the mounting nuts but DON'T tighten them yet!  If the car is a repaint like mine, line up the edge of the window with the edge of the new paint so it doesn't show.  Tighten the mounting nuts SLOWLY and don't force them.  The Butyl rubber seal has to have time to compress and displace between the window glass and the frame.  Let the Butyl seal set the pace by which you work.  Give each nut a turn and let it sit for a few minutes before turning it again.  Letting it sit in the hot sun also helped as the hotter the butyl seal is the more compliant it is.  Once the nuts are tightened all the way the trim around the window may stick up away from the body.  This is ok.  As the window continues to seat the gap will close.  pushing on the window evenly for periods of several minutes helps. 

Interior Reassembly.  I put the inside window trim back in the way it came out and didn't have to remove the door trim.  I think this is partly due to the heat this day and the resulting pliability of the plastic.  Inset the bottom of the window trim first and then push in the top.  Make sure the 2 metal clips catch the upper rail and the bottom snap drops into the hole in the bracket.  Reinstall the garment hook and the rear screw.  Replace the back panel and spare tire cover. 

I recommend resealing one side completely before starting the other side.  This way if anything doesn't look like it fits right you have the other side to reference.  I cleaned the window and the panels before assembly and it looks great.  Also, if you get some Butyl “strings or smudges” on the paint or the carpeting it easily comes off with mineral spirits, denatured alcohol or paint thinner.  Before using any solvent on the paint or carpet, test it on an unexposed area to be sure it won't melt. 

Remove the spare tire cover and the back panel covering the tail lights.  You may also have to remove the “300ZX” or “TURBO” reflector in the back as this partially overlaps the tail lights.  This is held on by 4 nuts and comes off easily (Click Image at Left).  Remove all of the sockets from the assembly.  Also remove the tail light sensor (little white rectangular box, right side on GLL models only I think) and the harness connector in the middle.  Remove the 5 nuts securing the assembly to the frame (Click Image Above Left).  Push the assembly out slowly.  Once you have it out, scrape off as much of the old sealer as you can from the assembly and the frame (Click Image At Left).  Don't waste your time trying to get it all off.  Leave a thin film.

Apply the Butyl rubber tape to the assembly staying close to the inside (Click Image At Left) and staying away from the edge.  Start at the bottom middle and join the two ends together to form a continuous seal.  Reinsert the assembly into the frame and tighten the nuts.  Reinsert and the sockets, sensor and harness connector and your done. 

Dead Tail Lights.  Here's a hot tip from Seth Herstad.  According to Seth, his tail lights had gone dead and couldn't find the problem until he looked at the tail light sensor, the 1x3 inch white plastic box on the right side tail light assembly.  The tail light sensor gives you a warning light on the dash when one or more tail light bulbs have burned out.  It had detached from the tail light assembly and was hanging up-side-down.  Water from the leak at the top of his tail light ran down the wires and into the sensor.  His sensor was corroded and knocked out his tail lights.  Once he replaced the sensor the tail lights worked again. Thanks Seth!  To see what other electrical damage a leaking tail light can do click here.

What I found is what I would consider a minor design flaw in the throttle assembly which could have grave consequences.  At the exit of the throttle cable guide is a rubber boot intended to keep out dust and water while flexing with the cable.  But after a decade the rubber dry rots and becomes brittle.  In these cases the boot breaks off and slides around on the cable.  It could remain this way for weeks, months even years.  Until, under just the right combination of acceleration, braking, bouncing, turning, and maybe timing and luck, the boot slips forward enough to wrap around the throttle half pulley with the cable.  The cable cant drop between the guides of the half pulley and instead rides on top holding the throttle open to 3000 or 4000 rpm.  The fix is easy.  Rip that sucker off of there and it doesn't happen again.

Removing the sending unit.  Pull back the carpet and sound mat in the back of the car.  There you will find a cover with 2 screws in the center of the floor with several wires coming through it (Click Image #1).  Unplug the connectors and remove the cover.  Below this is a plate with 6 or so screws and the wires attached to it.  This is the outer end plate of the sending unit.  Thoroughly Brush away any dirt and debris on and around the end plate.  Remove the screws and GENTLY start pulling the plate straight up (Click Image #2).  You may have to move it side to side and rotate but it will come out.  Do not force it.  The bottom end plate is held on with a retaining wire which can be bent and the end plate, wire, float and tube will fall back into the tank.  Then you're screwed.  Take your time and get it out in one piece(Click Image #3).

Disassembly and cleaning.  Holding the unit up-side-down remove the pin from the end and carefully remove the end cap and tube.  You MUST note the orientation of the float on a piece of paper or in your mind before sliding it off.  If you don't you'll have a 25% chance of putting it on right (2 180° increments times 2 planes of rotation).  The heart of the sending unit is a ceramic coated steel bar element with "printed on" carbon resistors and "lands".  DO NOT bend this under any circumstance!  If you do you will crack the ceramic and open the circuits.  It is pretty rugged so you would almost have to do so intentionally.  Get some Acetone, Tri-chlor, MEK or any strong industrial solvent (hardware store should have it).  Scrub the element with a paper towel and solvent several times until no more yellow/brown varnish comes off on the towel (Click Image #4).  You can also polish the long "lands" on the element with a Pink Devil drafting eraser or a pencil eraser(Click Image #5).  Inspect the inside the float for bent or missing leaf contacts.  Clean the tips of the contacts CAREFULLY with a cotton swab soaked in solvent.  Don't bend them. 

Electrical bench testing (Click Image #6).  Referring to the table below, and using an ohm meter, measure across the pin pairs indicated and look for these resistance values at the corresponding float positions.  Choose the data matrix for your type of dash.  Click image below to see float positions.

.DIGITAL (Numerical).........................ANALOG(Needle Type)

Pin +	Pin -	Float Position	Resistance Value In Ohms		Pin +	Pin -	Float Position	Resistance Value In Ohms
2	1	Full Empty ½ Full	Approx. 10 - 20 Approx. 480 - 520 Approx. 100 - 110		2	1	Full Empty ½ Full	Approx. 6 Approx. 80 Approx. 30 - 35
3	1	A B	Approx. 4 - or less Approx. 870 - 930		3	1	A B	More Than 60 Less Than 6
4	1	B	0		-	-	-	-    -    -

Reassembly and reinstallation.  Holding the unit up-side-down slide the float back on while observing the correct orientation.  Slip the tube and the end plate on.  Insert the pin under the "hook" in the end.  Before reinserting into the fuel tank be sure the rubber "O" ring seal is in place and undamaged.  This is important as the tank pressurizes during operation venting fumes and moisture could seep in during periods of inoperation.  Carefully negotiate the sending unit into the the fuel tank, fasten and reconnect the cable. Watch your fuel gage over the next few days and see what it does.  It may not be perfect but if it is working right it will be reasonably accurate and you will always know when your tank is full and when it is empty.

My water pump recently developed a sound not unlike a freight train.  The bearings were totally destroyed.  I am convinced the 3 defective Haynes fan clutches I went through last Summer did it in.  3 new clutches and none of them lasted more than a month.  A dramatization of how an unbalanced fan clutch will quickly shorten the life of a water pump.  The water pump is not hard to change but there are many layers of part that have to be removed to get to it.  The items in theimage at leftare all you need to remove in the order indicated to replace the water pump. 

IMPORTANT NOTE:  This is a good time to replace your timing belt, front cam and crank seals.  Leaking oil can shorten the life of your belt and a broken belt will almost certainly damage your engine.  Since I will be doing a total rebuild on this engine in the near future I skipped this step and therefore have no details. 

Remove the fan and clutch.  Back off the adjusters for the AC compressor belt idler pulley, power steering pump, alternator and remove the belts.  Remove the AC compressor idler pulley support member (that was a mouth full).  Drain the radiator and place a large pan under the engine to catch coolant.  Loosen the engine side of the upper and lower radiator hoses, let them drain and pull them out of the way or remove them all together.  Remove the crank shaft pulley.  You will have to use some kind of puller to get the pulley off.  I bought two 6mm by 60mm length bolts and used my steering wheel puller with great success (Click image at left).  The bolt takes a 22mm socket but a 7/8 inch also works well.  The bolt is a standard right hand thread so it unscrews counter-clockwise.  Remove the upper and lower timing belt covers. 

This is also a good time to replace your thermostat even if it seems to be working.  Also, if you have has trouble with overheating in hot weather you may consider a lower temperature thermostat.  Stock is 180°F.  I installed a 170°F thermostat which helped noticeably.   Remove the water pump and thermostat housing.  Keep track of which bolts came from where.  There are several lengths.  Scrape ALL of the old gasket material off of the engine face and both faces of the thermostat housing.  These surfaces must be clean and flat.  Install the new water pump with a new gasket using the recommended torque specification.  DO NOT use any sealer on the gasket.  This is not necessary as the gasket will provide all the sealing needed.  Install the new thermostat, new gasket, housing and torque to the recommended specification.  Reassemble everything in reverse order of the disassembly, set you belt tensions and top off with coolant.  Your done Dood! 

This seems to be a very common complaint when the first warm days of the new year come around.  Commonly this is a vacuum problem without any one particular cause or fix.  Any leak in the vacuum system can cause not only problems with the heating and air conditioning, but other engine performance related problems as well.  Check the 2 vacuum lines at the fire wall on the passenger side for cracks and leaks (click image at left).  One goes through the fire wall and supplies the climate control solenoid array with vacuum.  The other vacuum line controls the water cock.

These 2 vacuum lines run back along the fender well to the vacuum canister (click image at left).  Check all of these vacuum lines for cracks and leaks.  If they seem hard and brittle I strongly suggest replacing, not just these, but ALL vacuum lines in the car.  Looking closely at these lines you will find that all or most are color coded with a stripe.  At the canister there are 3 vacuum lines with a blue, white and red stripe.  You may not have to trace every inch of vacuum line to replace it if you can find both ends of the color coded ones.  Once you have identified both ends run a new line and pull the old one out or just leave it in.  This may or may not fix the particular problem you are experiencing.  The problem can be behind the dash in the heat/AC unit or the control unit.  I’ll have more information on this in the days to come. 
 

There are two ways to approach this problem.  You can replace the switch or bypass it.  Replacing the switch would be the right way to do it.  However, if it's an older car you don't know how fragile the radiator may be.  You could rip a big hole in it.  If you are unsure of the condition of the radiator you can easily bypass the switch which will have no ill effect on the car.  What will happen is the fan will run continuously only when the AC is on.  To do this, simply cut the wires at the switch (Click Image) and splice them together with a good crimp type blind or barrel connector.  DO NOT just twist the wires together and put electrical tape on them.  Do it right!

Theory of Operation.  The clutch is, essentially, a torque converter, very similar to the converter in an automatic transmission.  Prior to itsan.  Fast engine rpms, fast fan.  The problem with this is, at idle the fan barely moved enough air to cool the engine.  At high rpms the fan would cavitate.  That is, it would create a partial vacuum in the wake of the blades.  This would cause an annoying “Roar”.  Not to mention the aerodynamic drag that robs horse power.  At 4000 rpm a large fan could take 10 or 15 horse power right of the top of available energy.  The thermostatic fan clutch allows the fan to slip when the engine is cold and spin faster when the engine is hot.  The problem that had to be overcome with a viscous fluid clutch is that the fluid becomes less viscous as it heats and, thus, lets the clutch slip more.  Exactly the opposite of what you want.  To overcome this, all clutches have an external bi-metalic coil spring (Click Image) that, proportionally to temperature, opens or closes a bypass valve in the viscous fluid circuit. 

Symptoms of Malfunction.  Symptoms can vary widely.  If the clutch has lost fluid it may slip excessively.  It may allow overheating at low rpms but allow adequate cooling at highway speeds.  It may do just the opposite.  Or allow over heating under any driving condition.  Parts inside may come into contact after heating up and over spin the fan generating excess noise.  Look for oil on the outside of the clutch body.  Grab the fan (with the engine off!) and move it side to side while looking for excessive moings.  Rotate the fan by hand.  It should turn fry to give it a good spin.  If it rotates more than half a turn it may have lost fluid.  If you have an overheat problem that defies diagnosis, it may be the thermostatic clutch.  Something else to think about.  The clutch is “stack mounted" on the water pump.  If the clutch is bad, and out of balance, it can and often will cause premature failure of the water pump bearings.  Considering the clutch is often between $30 and $60, and you have a mysterious overheat problem, it is worth the price to replace.  Your water pump may thank you. 

Replacing The Clutch.  Replacement is easy.  Remove the black plastic cowling from around the fan.  There is the one bracket on top and several metal clips securing the bottom.  Hang on to the clips.  You'll have to jockey the cowling around to get it past the fan.  Next remove the four 10mm nuts (Click Image) holding the clutch in place.  To reach the nuts on the side hardest to reach, have the car in 5th gear with the parking brake off.  Push the car with your knees until the clutch rotates around to where you can reach the nuts.  Be careful not to disturb the pulley, however.  The pulley is held on by the same nuts.  If the pulley falls off you may have to loosen the fan belt to get it back together.  Once the clutch is off reverse the order of disassembly to install the new one.  Put this metal clips back on the bottom.  The top edge of the cowling hooks onto a groove on top.