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Well I got a weird issue with my taillights where they will turn on for my brakes and blinkers yet when I turn on my headlights my tails don’t turn on. But unlike what I normally see on here even with my headlights on they will still activate for my brakes and turns. Which makes me think that I am having a problem with my headlight switch but I don’t know if that’s the issue and I’d really rather not tear apart my dash. So I guess I am asking for ideas from the collective ans it were and short of those I’d appreciate a good wiring diagram for the tails and maybe the light Switch as well.
Just typing from memory here...
The tail "running" lights that should be on with the side markers and front parking lights are dual-filament bulbs. The brakes, turn signals, and hazard flashers use one filament while the running lights use the other. I'd check the filament integrity for both rear bulbs before doing anything else.
Bulbs should be #1157
Last edited by barkingrats; Apr 18, 2025 at 11:00 PM.
Just typing from memory here...
The tail "running" lights that should be on with the side markers and front parking lights are dual-filament bulbs. The brakes, turn signals, and hazard flashers use one filament while the running lights use the other. I'd check the filament integrity for both rear bulbs before doing anything else.
ok thanks I’ll check that out. But I was wondering if off the top of your head if you knew what color the running light wire is?
The tail light wire is brown. The left turn/ brake wire is yellow, the right turn/ stop wire is dark green.
open up the harness at the drivers side sill plate. Between seat and sill plate underneath the carpet. Find the brown wire, with lights on, does it have power, yes, keep working back to the rear lights, No, go forward.
do the front running lights light up when headlight switch is pulled to the first detent? If yes, it's not your light switch.
Ensure that the dual filament bulbs are inserted CORRECTLY. The advanced age of the bulb holders and abuse, people sometimes insert the bulbs the wrong way ( the brass receiver for the pins are distorted). The taillights are wired through the turn signal switch in the steering column which is not too bad to replace. As previously stated, spend some time cleaning and examining the bulb holders, corrosion can be a problem along with poor grounding. LEDs will also cause problems, although you don’t mention that your car has them. If you try a Google search there are some extremely helpful step by step tests to help identify your car’s troubles. Unfortunately not every year C3 Corvette has the same Wiring Schematic. There are some free wiring diagrams floating around, you just have to search for them, or simply buy a 73 Chevrolet Service Manual on eBay.
Strange tail light issue.
