Tail light problem

Strange...

There are two types of headlight switches.... One has a jumper from the headlights for the dome light power pin which on the other switch this pin with no jumper from the headlights controls or looks like it comes from the park light fuse for the park lights instead of getting power from the headlights. Or something strange like that.

The cutoff for the headlight switch swap is 1979 for a before and after on the two different ones.

I have a JPG of the difference if you would like it emailed.

That still wouldn't explain the brake and signal light failure though, that implies a loss of ground to me, hmm.... OK, it does make sense.

The rear light fixture bolts must provide the ground path for the brake and signal lights 'or' they will steal a ground through the running light bulb filaments because the rear running lights use a wire to ground them. This only works until the headlights come on....

So I am thinking you are maybe missing a body ground on the rear fixtures or the tub itself has lost it's ground and you have the wrong headlight switch in there.

Mike

You will have to tie the negative leg of the LED's to the ground directly. Where are you stealing the ground source from now? Where are your running light LED's grounded?

Sounds like you are trying to use a common ground for both.

Hmm, do you maybe need a diode in there to stop the brake lights from backfeeding through the lower amp running lights?

Mike

Greg wrote:

Well just about to give up, I ran a ground wire from the two LED lights ground prongs to a ground block I have under dash, and that was it, got all lights working, brake, turn, tail, turn and brake with tail. So made permenant conctions to all with some 3 prong plug connections from NAPA, gave a test, now I have only one brake light, but I have turn and tail. Stripped it all back to start again, still only one brake light, traded lights, still same one brake light. I've gone right back to aligator cli[ps connecting everything like I had earlier when I got all working, still only one brake light.??????????

That tells me you might have a bad connection on that side. Could be a bad crimp or a connector came loose.

That tells me you might have a bad connection on that side. Could be a bad crimp or a connector came loose.

Or... a bad light?

I traded lights side to side, same thing on same side. And to Doug, I have taken all connectors back out, and useing just aligator clip to join, same thing.

Something get shorted and blow a fuse? (dunno if there are fuses for both sides, just gussing at this point)

I get the same issue now and then and believe I have a punky connection at the brake light switch itself.

Got pulled over by the cops once and all I could get working in the rear was one signal light, no brake or running lights. After putting in new fixtures because mine had rotted to nothing, I still only had one brake light, the drivers side. If I hit the pedal a few times it came back to life and more or less stayed working.

Do you have each fixture separately grounded? I mean a ground for each brake light bulb.

Mike

Greg wrote:

I was running only one ground wire for both lights, I can try 2 but don't see how that would make much difference. And please don't say each bulb, I think there are 9 in each :)

Multimeter time then I would say to eliminate needless wiring.

Do you have power coming to both sides when the brakes go on?

I just looked at the book and the common power point is in the signal switch and hazard switch.

That would explain why one side of mine was strange, I was running that signal for a 'long' time because it was all I had showing in the rear at night on the first leg of a 4000 mile trip as the police 'escorted' me to the nearest garage and that was the side the brake light didn't want to work well on so the contact likely got overheated.

They also go through the Hazard lights. I have heard of folks fixing wonky brake lights by cycling the hazard lights.

Mike

Greg wrote:

Well went through the whole thing again, grounded each light seperately, got it all hooked up and it works, well sort of. I was showing my wife, brake lights, yes, tail lights, yes, tail and brake, yes, signal, yes, brake lights again, no, only one again. So started playing with switches, headlight, ok, signal, not ok. I can now get brake lights to work untill I turn on signal, whichever way signal is turned, that's the brake light that will work after. So time for new turn signal. Part is cheap, anyone got advice or a step by step on changing that. There aren't many things that haven't been apart on my jeep, but column is one. I do have another column that came out of my frame donor jeep, so could play with that one, but would still like a step by step or at least watch fors. Nothing like taking something apart for first time and 3 plates and 1/2 dozen springs drop out.

"Mike Romain" wrote in message news:488c911e$0$14206$ snipped-for-privacy@unlimited.newshosting.com...

Unless you have fingers like vise grips, you will need a 'GM lockplate' tool. Canadian Tire will loan these out. It is for compressing a plate inside so you can remove a circlip holding the plate. With two people, one can push like mad and the other can usually pop out the clip, but it is a pain without the tool.

I would recommend you take a photo of the horn assembly before taking 'that' apart, it can be a hassle.

You might find a parts blow up of the column on line. It is a Saginaw column like the full sized GM's use.

Mike

Greg wrote:

Thanks, I just did a google search, found how to rebuilt a GM steering column

Bless your heart Greg... I believe you're going go get it fixed! I admire your stubborness.