Need some lighting help. Badly

[GT400]

:1zhelp:

Ok, before anyone asks, i've searched, gone through the TSRM, and traced wires till my fingers bled.

My dash, tail, and stop lights have quit working. they were working for the first several minutes the car was running then went out, but now they blink on sometimes at random, but generally they are just out. the tail and brake fuses are not blown, the relays have been swapped, the circuit breakers are new, i put in a new taillight failure box, none of the taillight bulbs are blown, and the headlights still work, although the fog lights do not.

i'm just stumped. i'm fairly good with trouble shooting and wiring, but i cant figure this one out. some of the threads that came up in the search were similar, but their fixes didnt fix mine.

Daniel

 

[shenronzero]

sounds to me like you might have a loose wire somewhere... i know thats not what you want to hear but blinking lights usually points to a band connection of some kind. but i think i remember of something like this happening not to long ago and it had something to do with the dimmer switch (i know thats not its proper name for it) located on the bottom of the pannel with the fog light switch. sorry i couldnt be more help

 

[hvyman]

ground points are a,c,d,h,k on this page for that circuit.http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=151

the dimmer switch should be if the tail lights work but you could check the resistance in it and maybe that would be the problem for the gauges.

does it rain a lot in your area the grounds for the tails in the bulb holders could be corroding and not be giving a good ground if the seals are bad
also check the gauge fuse.
also check the stop light switch.

 

[kingofyo1]

ground points are a,c,d,h,k on this page for that circuit.http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=151

the dimmer switch should be if the tail lights work but you could check the resistance in it and maybe that would be the problem for the gauges.

does it rain a lot in your area the grounds for the tails in the bulb holders could be corroding and not be giving a good ground if the seals are bad
also check the gauge fuse.
also check the stop light switch.

this and the grounds.. definately check them, the grounds at least have been a concern for me for a couple months since i got my supra... previous owner did bad grounds. found this out with my multimeter

 

[IJ.]

Welcome to SM Drew, it's NOT a starter

 

[antman]

Check the dimmer and the switch itself.

 

[GT400]

thanks guys, i will keep hunting.

 

[kingofyo1]

goddamnit grumpy, please do NOT bring that shit up lol since that comment on supraforums.com, i have gotten smarter i have since realized that a windshield wiper motor is NOT a starter, no matter how hot it gets ^^ i have actually gotten really good at picking out fixes for problems engine wise, as well as electronics wise!

oh btw, sorry to get off topic there, as far as on topic, i doubt it could be the stop light switch, as if anything in it is messed up all it will screw up is the stop lights coming on and off, not dash, tails, etc. i just had a prob with my stop light switch, and lemme tell ya monkeying around under the damn drivers side dash is a bitch. especially when you're too damn tall to do it correctly even with the seat back all the way! as far as gauge fuse, if it was blown, then they would not come on intermittenly, but not at all. if it is the connections TO the gauge fuse, that is a different issue.

just my $0.02

 

[GT400]

yeah i dont fit under the dash either at 6'2". i havent had a chance to get back to it yet, but i appreciate the input.

D

 

[GT400]

Ok, im still stumped. i've gone wire by wire, literally with the toyota wiring diagram in one hand and a multimeter in the other. when the lights are working, everything is perfect. 12.8 volts everywhere, perfect continuity on all wires. when the Lights go off after being on for a few minutes the main power wire in to the fuse panel under the dash drops to about 3 volts. the same wire has 12 volts at the end near the battery, at the 100 amp fuse. if i unplug the wire from the dash fuse box, it has 12 volts, but if i plug it in, it drops. WTF is going on.

 

[kotu100]

perhaps corrosion in/on one of the wires or connectors causing unwanted resistance? just a suggestion