Lights (lack of..)

[gwaidman]

Having a recurring problem with left rear brake / flasher circut. When signaling left, I get the rapid flashing indicator. Front turn signal flashes, rear doesnt. Apply brakes, no left brake light. I have checked the bulbs, and connections in the rear light housing. Looks good. This problem will sometimes correct itself after a dozen or so cycles of the flashers. Usally doesent come back for a few weeks, but the problem is getting progresively worse. Really bad as of lately. I have really gone through the wiring decently, and so far as removing my trailer harness. No change. The rapid flash would seem to indicate an open circut somewhere down the line. Not sure if it is on the brake or signal circut. :( Any one have any thoughts on this? I hope that I am overlooking something painfully obvious... As well, if there is a wiring diagram available out there?

[a5150nut]

Had to replace the turn signal switch in the colum to cure my problems like yours. Check the adjustment when you install the new one.

[gwaidman]

a5150nut,

What 'adjustment' are you reffering to? Was this a easy job?

Thanks for the info!

[tom.mcinerney]

You may want to run extra battery(-) or block to frame ground. on '95 the tail lamp harness gets ground from frame...frame gets ground forward from block via braided line that deteriorates. Ignore if rear lamps otherwise bright & cheerful.

[gwaidman]

Thanks guys,... Tore into the colum to explore the turn signal switch. Contacts look good and are now bright and clean. No luck. As well, I re/re'd the ground terminals to the frame. Nothing. My voltmeter shows climbing / falling voltage at the light harness, so I know that there is some juice there. Same test with test light and no light.. I am thinking that the wire has been damaged somewhere, as it would seem that there is very little current, simulating an open circut similar to that of a burn bulb, triggering the rapid flash. Hmmm. Anyone with a wiring diagram they could email me?

Cheers! :confused:

[HowieE]

I can e mail a 96 diagram which should be the same but need an address.

[gwaidman]

HowieE, That would be great. email to gwaidman@hotmail.com

Thanks!

[tom.mcinerney]

You've probably noted that the plastic lamp housing can distort with heat; the 'tabs' on the bulbs wear away the slots in the base, the bulbs squirm out of position. Have replaced bulb? The solder tabs at base sometimes don't make good contact when corroded (sometimes polishing solder dots fixes.

Not surprising both brake and signal suffer since they share wires/filament. '95 Helm shows current from 'Stop/haz fuse1,15Amp' to Stoplamp Switch, to 'Turn/Hazard Switch'. Then connector C266 by steer col & firewall; then connector C104 under brake MC, in engine compartment; then connector C409, just ahead of rear bumper. If connector 104 under brake master cyl is soaked in mix oil/brk-fluid/road salt, it could deliver results you experience.

Trailer tow optional wiring appears to add a separate turn flasher, hazard flasher, and 'Stop Lamp Relay' to the mix, seemingly between the turn/hazard switch and the connector C266 {in cabin, not engine bay}.

IN EITHER CASE, on '95 the wire from the turn/hazard switch to the left side stop-turn tailamp is YELLOW; to right rear lamp is DARK GREEN. Both wires are .8mm diameter from (col)switch to connector 104 beneath Master cylinder. Thereafter the wires are 2mm diameter , for the run to the rear bumper harness. I think you'll identify about a 5-wire harness connector running back?? good luck....

[jspringator]

I had to go into the lamp base and pry out one of those little tabs that wasn't making contact with the bulb. I used one of those small precision screwdrivers. You can tell if this is your problem if you wiggle the bulb and it starts to work.

[gwaidman]

Thanks for the info gents. Turns out the yellow wire to the rear left assembly was broken inside. I took no chances and ran a new 16ga wire from the steering colum connection all the way back an this has fixed the problem. On the bright side I am now very familier with the signal / brake schematics for this truck. :rolleyes: