Electrical Gremlins

[Equalross]

Hello

 

       I am looking for some advice on chasing down an electrical issue. on my way home a month ago my temp gauge started going a little haywire. it kept going from luke warm to hot and repeat. first sign of something is up since the engine was not hot. When I got home I turned off the lights and car. I then pulled them back on and instantly no dash lights and also no right side parking light. I had ran into this before where a bad ground on the that passenger light caused both to be out before. no idea why one affects the other. I  bought new screws and re tapped the holes for a clean ground through the screws. still nothing. I then went to the dash. Prior to this I had already added grounds to the two screws for the temp and gas gauge a few years ago. I pulled out the dash and fiddled a little with the connectors and put it back in. suddenly lights worked. this is where I went wrong. since it seemed to fix it I pulled the dash out and put a little dielectric grease on the pins to help make a better contact. put dash back in and now no lights. since then I have cleaned all the connecters.  wipe off the grease. pulled the ground wires and cleaned all contact parts on the screw I grounded to. still nothing. I have a spare light switch so I changed that for fun. no change. back to dash. turning on does make the gas gauge work and oil and L lights will light up blinker too. speedo works. tach too. just no dash lights and of course my right passenger parking light. I have pulled the dash apart and noting is obviously fried.  at this point I am at a loss and any help would be welcome. 

 

Thank you

[Mike Self]

When you have electrical gremlins on an '02, the first thing to check is the fuses.  Just because they look OK doesn't mean they are.  The ends can wear through where they're clipped in place, and even a little corrosion at those contact points can cause connectivity problems.  So check 'em first.

 

The wonky temp gauge is most likely a bad ground for the gauge.  Do a search for "grounding temp and gas gauges" and you'll get instructions on how to run a separate ground wire for those two gauges.  

 

No dash lights can be caused by a failing rheostat in the headlight switch, which governs the dash lights brightness.  Turn the lights on, then rotate the light switch knob to see if the dash lights suddenly go off.  That's probably a bad (or just dirty if you're lucky) light switch.  

 

That'll get you started on your troubleshooting.  Report results and we'll delve deeper if necessary.

 

mike

 

PS...parking light: Does the turn signla light blink?  If so, then the ground is OK.  But didja check the bulb socket for corrosion?  Remove unit with the wires still connected, then use a jumper wire for a temporary ground, and wiggle the bulb in its socket.  

[Equalross]

MIke.

 

Thank you for your response.  I had stated in my post I had already grounded the temp gauge and gas gauge a few years ago. I also stated that I switched out the whole light switch assembly already since I had a spare. I did try the fuses. cleaned all the contacts and put new ones in. no change. I don't think it's that anyways since most of the instruments work including the trouble lights and blinker. so power is going to the panel. I agree it has to be a ground issues somewhere.  Yes parking light means turn signal. I have not tried wiggling it while it is out and re grounded. I will try that next. I still wonder how in the world that turn signal and dash can effect each other. The wiring diagram doesn't seem to show connect but they must share a ground somehow. I am also going to start testing the pins on the connector next for power. 

 

Thank you for the advice!

 

Collin.

 

[John76]

3 hours ago, Equalross said:

must share a ground somehow.

What year is your '02?

I've counted 42 ground points on my '76... and still finding them!

Here's a crude sketch of the parking lights, turn signals, hazard flasher that I started a few years ago... but haven't finished.

Hope it sheds some "light" on your problem.

Happy Holidays,

John

 

[tech71]

 Forget the grease. Use this on your connectors.

Fixed my intermittent wipers.

Edited December 18, 2022 by tech71

[Mikesmalaga72]

You say you already made a ground provision for your gage perhaps double check it? Headlights are not designed to turn on with the car ignition switch off.

 

Turn on parking light at switch any key position including off, then using a phillips screwdriver to each of the retaining screws at turn signal retaining screws twist them back and forth until you get light lit providing that the bulb assy is serviceable. Turn off head light switch.

 

Edited December 19, 2022 by Mikesmalaga72

[Mike Self]

6 hours ago, Mikesmalaga72 said:

Headlights are not designed to turn on with the car ignition switch off.

On the pre-modell 71 cars (166/167XXXX VINs) the headlights will come on with the ignition off; on later cars, they're wired through the ignition so the headlights go off when the ignition is turned off, leaving only the parking and tail lights.

 

mike

14 hours ago, Equalross said:

I still wonder how in the world that turn signal and dash can effect each other.

That may well be two separate problems that just happened to rear their ugly heads simultaneously.  A non-functioning turn signal can make the flasher relay blink faster, but shouldn't affect the dash lights.  The dash light problem may be a bad spot in the dash circuit board. 

One more thing...before installing a new headlight switch, did you test the two terminals that feed the dash lights (they connect to the switch's rheostat) with an ohmmeter to make sure the rheostat is functioning properly--especially if it wasn't a new switch.

 

mike

[Mikesmalaga72]

I did not know that the headlights were not wired through the ignition on the very early cars...Thanks for letting me know Mike!

Edited December 19, 2022 by Mikesmalaga72

[John76]

If you want the headlights to work with the ignition "OFF"... you can just remove the Green wire from the ignition switch and connect it to the Red wire.

How festive...red, green and white (light).  😁

But hopefully no fireworks!