The taillights on my 1964 Jetstar 88 no longer turn on when the headlight switch is pulled out. The glove box lamp, underhood lamp, instrument panel backlights, license plate light and trunk lamp all no longer work. However, the headlights (low and high), brake lights, turn signals, dome lamp, map lamp, idiot lights, and reverse lights still work.

Any ideas? I tried replacing the headlight switch and cleaning up the battery terminals, but nothing changed.

 

Taillight fuse? Be sure to actually pull the fuse out, don't just look at it in place. The element can break or burn out under the metal end caps. Also corrosion on the contacts can cause a problem.

 

Take a wire strip it on both ends and ground it out between the tail light housing and any clean metal you can find in the trunk and see if you just have a bad ground....

 

How does a bad ground in the trunk cause the underhood, instrument, and glove box lamps not to work. Sorry but all of these are on the same fuse and circuit:

 

Under hood, glove box, and trunk lamps i think are on a different circuit than instrument panel lights and license plate light.Not sure without looking at wiring schmatic.

 

Obviously, nobody is.

All of the non-functioning devices are powered through the taillight fuse, as Joe suggested.

Sometimes you can save a lot of time, money, and energy by looking at the schematic first.

- Eric

 

Better look at that schematic again. They are all on the same circuit. The instrument panel lamps have an additional loop where a feed from the tail light circuit runs back into the rheostat on the headlight switch, but it's still fed from the same tail light fuse. The license plate lamp wire splits off from the tail light wire in the trunk harness. On a 1964 full size, this circuit uses a black wire. The same black wire goes into the rheostat. A gray wire out of the rheostat feeds the instrument panel lamps.

 

I have a similar problem, just swapped out my rear light housings because the upper lights were not working (one socket was completely shot and came away from the housing). now both upper and lower lights flash when i engage the turn signal but they do not come on for braking or when i turn the lights on for night driving. any ideas?

 

Your problem is a classic ground problem. Check all grounds at the bumper and housing.

 

and the grounds are those metal clips that attach to the inner-upper tail light housing and then again on the backup light bracket?