Flashers, brake lights and taillights problems

[SFC Cobb]

I turn the 4 way flasher or turn signal on and the lights flash but dimly. When I turn on the headlights the flashers go off and the taillight and the side clearance lights (dually) and the clearance lights start flashing. With one turn signal on both taillights and all the clearance lights flash.

Could the BCM (Body Control Module) be the problem? I don't see anything obvious wrong with the wiring.

 

[handcannon]

I don't know for sure, but maybe grounds. In the old Toyota Landcruisers these kind of problems are usually grounding problems. Instead of grounding where they are supposed to the system hunts for adequate grounding and by going where it shouldn't all kinds of wierd things can happen. I don't know where the grounds for the lighting is but the info should be somewhere on this site.

Don

 

[CtChevy427]

Look at the easy things first. I would run around the truck and make sure all your bulbs with more than one filament are good. A few months back I had a filament break off on the side and drop onto the other good filament. It was sending current where none should have been. Drove me nuts for a good while.

 

[BigBlueChevy]

Defiantly check what the status is of your grounds to the frame. Could be a rather corroded ground connection that just needs some TLC. Have you worked on the truck at all (or had someone else working on it) that may have ripped or damaged a ground strap?

 

[NVW]

x3 on grounds, I've had some strange problems with a bad ground.

 

[orrum]

x4 on grounds. Grounds, grounds, grounds!!!! If u wanna b a diesel mechanic u gotta have permanantely sooty black hands and u gotta work them grounds, grounds, grounds, I am tellin u its all about them grounds! Ya;ll know about the woodchuck chuckin wood????? :mad2:

 

[jrkrace]

Trailer plug could be a culprit as well. Similar symptoms when I had my 95 Sierra.

 

[benjammin]

Look at the easy things first. I would run around the truck and make sure all your bulbs with more than one filament are good. A few months back I had a filament break off on the side and drop onto the other good filament. It was sending current where none should have been. Drove me nuts for a good while.

I've also seen this, make sure to check them before wasting time on the difficult stuff.