AE86 dash and running lights gone out

[Mikezore]

Okay this is long winded so stick with me. When I got the car the dash lights acted up but a quick bang on the dash normally brought them back on. I pulled the cowl around the gauge cluster off wiggled the connector on the headlight switch and they worked fine for a while.

Recently they quit working all together. I attempted the same routine but to no avail. So started digging through the wiring diagram and doing some tests and cannot find a damn thing.

At the light switch I have 12v at pins 8, 4 & 7. The tail light relay functions normally and no fuses are blown but I cant get the damn things to come on. An ohm test across the pins of the light switch shows it to function as outlined in the manual. I went ahead and got a new switch since the rheostat was dead and still nothing..

I've torn the dash out and checked every connector but found none loose or any that with a some jiggling brought the lights back to life. Checking the wires that supply V and G to the dash lights revealed something odd though.
Pin 1 on the light switch is a black wire with orange spots. It is the same color as the wires that run to all the dash lights and an ohm test confirmed that they do indeed comprise the same circuit.

Since bypassing the rheostat involves connecting this wire to ground, I assumed the other wire for the lights (Green with Orange spots) would be the V side. But an ohm test reveals the green with orange wire shows a connection to ground.
I started disconnecting connectors from the fuse block until I lost continuity and this revealed the continuity to ground being through the running lights circuit.
I'm at a loss as to where to go next. The only sign of tom foolery I've found is the Black with orange wire (pin 1 at the light switch) has been cut and re-connected via crimp connectors directly behind the light switch, and directly before the gauge cluster.
I've cut the crimp connectors out and reconnected the wires properly to eliminate them as a problem but still no change. Can anyone suggest anything? I'm bout to lose my mind.. what shouldve been a quick fix has turned into a gutting my car nightmare, that I want to end.

The factory service manual I have doesnt list wire colors, so I've been having to use process of elimination but at this point its looking as if I may have to pull the dash support just so I can cut the harness loose and crawl over it begining to end. But before I do that I was hoping someone out there has encountered this before and can point me to the trouble spot.

I appreciate any insight or thoughts into my predicament.

[pack]

Just "chant" like we say in Portugal and create yourself a "ground" connection. Problem solved.

Use a diode so you don't mess your wiring...

[fax0815]

I´ve had the same problem a while ago, can´t remember any wire colours, but all I did was splicing in a seperate wire into the negative from all the dash ilumination to on the dash clock plug, connected it to a good ground and never had any problems again. On a note, you´ll loose the dimmer function of the dash clocks.

[Mikezore]

nope not the ground. I clipped a test lead from the ground pin to a good ground and nothin happened. ohmed the existing ground and it was less than half an ohm so its good. any other ideas?
im beginning to suspect the fuse box maybe... but it still wouldnt explain why for a while i could wiggle the connector at the switch or bang on the dash and the lights come back on..

[Mikezore]

something else interesting just found. my fuse cover was missing so i couldnt id the fuses. found a pic of the cover and the master tail fuse wasnt even inserted.. put one in and nothing happened, checked for voltage and and found nothing. its very odd because they had been working before even without the master fuse inserted..

[ditn]

you need to use some enters very hard to read
if i understand correctly your dashboard lightning isnt working anymore?
I have had this problem before and switched the headlight switch and it worked again.

[Mikezore]

ditn Wrote:you need to use some enters very hard to read
if i understand correctly your dashboard lightning isnt working anymore?
I have had this problem before and switched the headlight switch and it worked again.

better ?

[max_ae86]

Mikezore Wrote:i could wiggle the connector at the switch or bang on the dash and the lights come back on..

Exactly what has happened to me. The switch was the cause. I pulled out the switch and after close inspection found that one leg was losing contact on soldered part of circuit board probably due to vibrations over the years. It was almost impossible spot. Just go and carefully check the soldered contacts in the switch. :wink:

[Mikezore]

ive already installed a new switch.. I did some voltage drop testing tho and found that the taillight relay, tho it is working, has a bad switch connection. it only shows about 5 volts when engaged. I ordered a new one and will be going to pick it up shortly. I'll let yall know how it turns out.

[Mikezore]

well new relay yeilded nada.. the new one showed the same output voltage so i can only assume its internally resisted down because the output from it runs to the headlight reatiner relay.
Which on a side note i opened up to exaine and is not a relay at all but a transistor based timing circuit that control the auto off function on the lights..

So I'm back to square one. gonna do some more disassembly and trace out some wires...just cant figure out why the initial diagnosis was so obviously the switch but now im running in circles hunting a wild goose..