Electrical help

[hitthebricks]

On my 05 2500 HD Chevy puckup I thought I had a problem with the flasher solenoid but I think I'm wrong about that. Problem I have is turn signals work but

left side works but rear running lights dim when it flashes

left side stops flashing when I step on brake pedal

electric brake controller lights flash when the left signal is used like when the trailer is connected.

Right side works like it should.

Any Ideas on where to start looking?

Thanks,

HTB

[CAMAN]

Grounds, check 'em all!

[Jeremy airjer W]

Agreed, you have ground issues.

[hitthebricks]

Grounds for what? light, flasher, trailer connection, power in general?

[Macgyver55]

The first thing I would do is pull off the left rear tail light assembly and check the bulb sockets for corrosion or burned contacts. If all looks good disconnect the main harness connector for the light and also check that for corrosion inside the connector. If that looks ok get out the multi-meter and begin checking the ground circuit there.

[hitthebricks]

Cant find a bad ground anywhere. Cleaned contacts, no corrosion found. Now it really looks like the 4 way flashers are on when I turn left but only the tail lights are affected. Would th plate where all the harnesses connect go bad?

Thanks for the help so far

[Macgyver55]

Did you check the bulbs closely to make sure that one of the filaments is not broken and touching the other filament.

[Whoaru99]

Can't remember what truck it was...Chevy I think, where that taillight housing itself sometimes goes bad. Don't remember the details though.

[Macgyver55]

It was the circuit board on the earlier models (in the 90s) that had the problem.

The newer ones no longer use that style.

[hitthebricks]

I figured one last ditch effort before I brought it to Schaleen elect. The original first thought I had was the flasher solenoid was bad. Guy at NAPA said no way you guys confirmed that . After a day checking grounds, bulbs and connections I swapped flashers with my burb and found my problem. Who would have thought a a basic flasher could create so many different issues.

Thanks for you help guys. This whole mess I think is GM's plan for sole and exclusive repair and diagnostics rights for their products.

HTB

[Macgyver55]

If you put the bad flasher into the vehicle you swapped with do you get the same result?

[hitthebricks]

Yes I did, same problem. Installed the new flasher this morning and nearly found nirvana. I hate electrical problems, I only know enough to get myself in trouble. Most other problems with cars I don't have a problem drawing the line of when I should bring it in or can do myself

Thanks again,

HTB