'63 lights, ground straps

[Steve D.]

When I pull the light switch on, the headlights come on properly, but the tail lights are very dim, just barely visible. If the headlights are unplugged, the tail lights are still at the same dim level. However, when the turn signal switch is turned on, the tail lights blink at a normal (acceptable) brightness. Someone suggested that there might be a ground problem. Does that sound likely ? I've seen in the manuals that there are several ground straps, but I have not chased them all down to see if they are in place. What functions are they critical for?

Steve

[Duke W.]

Re: '63 lights, ground straps

The fiberglass body means that all the lamps and most other electrical devices have dedicated grounds. If your tail lamps are misbehaving, check all the individual lamp grounds. Typically the ground wires are in the wiring harness and the ground wires attach to the body of the device via one of the mounting fasteners. Most of the ground straps on a Corvette are part of the RFI supression system for radio equipped cars.

After over thirty years it's also common to have some resistance build up in connectors, so a systematic inspection and cleaning of all electrical connections is not a bad idea. Inspect them with a magnifying glass, dress any corrosion or deposits with a small brass brush or Xacto knife (DO NOT USE SANDPAPER) and give them a good hosing with electrical contact cleaner. Follow this with a WD-40 hosing or a thin film of silicon dielectic grease. I prefer WD-40 on low voltage connections, but use silicone dielectric grease on the high voltage igntion connections.

Cosworth Vegas are commonly afflicted with intermittant gliches in the EFI system and a systematic check of all the EFI connectors usually returns the system to its seemless OEM performance. Electrical control equipment is more senstive to small resistance buildups in connectors than lamps or other high current devices like motors. I can only imagine the glitches that modern cars with their multitude of microprocessors will experience if they make it to the age of our vintage Corvettes!

Duke

[Duke W.]

Re: '63 lights, ground straps

The fiberglass body means that all the lamps and most other electrical devices have dedicated grounds. If your tail lamps are misbehaving, check all the individual lamp grounds. Typically the ground wires are in the wiring harness and the ground wires attach to the body of the device via one of the mounting fasteners. Most of the ground straps on a Corvette are part of the RFI supression system for radio equipped cars.

After over thirty years it's also common to have some resistance build up in connectors, so a systematic inspection and cleaning of all electrical connections is not a bad idea. Inspect them with a magnifying glass, dress any corrosion or deposits with a small brass brush or Xacto knife (DO NOT USE SANDPAPER) and give them a good hosing with electrical contact cleaner. Follow this with a WD-40 hosing or a thin film of silicon dielectic grease. I prefer WD-40 on low voltage connections, but use silicone dielectric grease on the high voltage igntion connections.

Cosworth Vegas are commonly afflicted with intermittant gliches in the EFI system and a systematic check of all the EFI connectors usually returns the system to its seemless OEM performance. Electrical control equipment is more senstive to small resistance buildups in connectors than lamps or other high current devices like motors. I can only imagine the glitches that modern cars with their multitude of microprocessors will experience if they make it to the age of our vintage Corvettes!

Duke

[Steve D.]

Re: '63 lights, ground straps

Duke

Thanks for your comments. In checking the ground, should I be looking for a wire coming out of the harness that connects to the frame ? If so, I will probably need to remove the valence below the bumpers to expose the harness ?

Steve

[Steve D.]

Re: '63 lights, ground straps

Duke

Thanks for your comments. In checking the ground, should I be looking for a wire coming out of the harness that connects to the frame ? If so, I will probably need to remove the valence below the bumpers to expose the harness ?

Steve

[Duke W.]

Re: '63 lights, ground straps

I believe the grounds for the tail lights are in the harness. They are usually black wires. I'm not sure how the ground circuit reaches the battery, but the wiring diagram in the '63 Corvette Shop manual should show you the way.

Removing the rear valence will make the area more accessible and it's not that hard to do, but you do have to remove the tailpipe extensions first.

Duke

[Duke W.]

Re: '63 lights, ground straps

I believe the grounds for the tail lights are in the harness. They are usually black wires. I'm not sure how the ground circuit reaches the battery, but the wiring diagram in the '63 Corvette Shop manual should show you the way.

Removing the rear valence will make the area more accessible and it's not that hard to do, but you do have to remove the tailpipe extensions first.

Duke