another ground issue

[acl]

all lights on the 68 work until- i have no brake lights when using turn signals, they work fine seperatly. read alot of forums,, talking about ground. Have cleaned bulb socket, and where light cup touches bed, where should i look for the "ground strap" from bed to frame???? Any other thoughts would help. Gary

[gcburdic]

I installed one from a bed cross member to the frame...I believe on the passenger side

[acl]

if I were to look for the "factory" ground, where should I look. Hoping i can clean that one up.

[68gmsee]

I'm don't think there was a ground on the bed to the frame from the factory.
Never seen one.

When these trucks were new the bed bolts served as ground to the frame but in 40+ years rust and grime have created poor connections. Adding some on your own will help eliminate a lot of problems.

Be sure and create a good metal to metal return to battery negative. Don't forget the one behind the engine to the cab. I even placed a strap on the radiator support to battery neg.

[BMERDOC]

I used a 16 gauge black wire and terminated the ends. I routed the new wire underneath the bed with the wiring harness on the passenger side. I put a stiff wire through the bottom hole of the passenger taillamp bucket, threaded my terminal over the stiff wire and installed the bucket to the bed aligning the whole thing. I installed the top screw and tightened it but not completely. I then removed my stiff wire, now the terminal is sandwiched between the tail lamp and the bed. I added my bottom screw and tightened the whole thing down. I then terminated the other end and used a machine screw, matching nut and a two washers to bolt it through a freshly cleaned exsisting bolt hole in the frame. My tail lamps now shine like brand new and three ground associated problems disappeared!

[Longhorn Man]

your grounds are fine if they brake lights light up at all.
Sounds like a bad turn signal switch to me.

[JCD]

I second Longhorn..
I recently chased the working and non working of my brake lights in the Corvair.
After spending hours trying to wire and rewire and test grounds..it turned out to be the signal switch in the steering column.

J.

[Longhorn Man]

it is a 99.9% chance.
The brake lights and the turn signals work off the same filliment in the bulbs, the same contact in the light socket, the same 2 wires on the chassis rear lighting harness, and the same terminals on the plug going to the turn signal. The ground handles the same amount of amps for a turn signal as it would for a brake light, since electricaly speaking, they are one and the same... so we know the ground is good.
Working from the other direction...
We'll know the fuse is good since all other lights work as stated in OP's post. (both the tail and brake lights are powered by the one fuse.) The brake light switch works, he said the brake lights do in fact come on with the turn signals aren't on. The next thing for the power to go to is the turn signal switch.