heritageadam

I'm having trouble figuring out why the trunk light in my 1979 Olds Regency 98 is not working. My voltage tester lights up when I touch it to inside where the light bulb sticks in, but not on the part in the middle which looks like where it actually touches the bottom of the bulb. When I put the bulb in it does not light up.

Thinking it was a problem with the fixture, I pulled the part out of my identical parts car (fixture and about 6 feet of cord which then plugs in). Same thing with that wire/fixture combo. Tried 3 different bulbs in both fixtures.

I've got + voltage where the wire plugs in to the left rear part of the trunk, as well as + voltage inside the where you stick the bulb in as listed above.

What am I missing here? What makes the light turn on when trunk open/off when its shut?

Thanks.

jcdynamic88

did you check for ground at the socket? you need a ground as much as you need power.i believe this uses a mercury switch that completes ground when you open the trunk.ive had cars that required the parking lights on for the hood or trunk light and some that didn't(I think older models)jc

radioburningchrome

X2 on the ground.

My 1980 Cutlass trunk light works all the time, my 1965 88 needed the parking lights to be on.

Redog

I agree on the ground, and my Delta's trunk light works all the time, but the underhood light, parking lights have to be on

heritageadam

This is probably an incredibly stupid question but how do I figure that out? (ground) There is only one wire with the power going to the fixture. The outside of the fixture is metal & screws into the trunk. My parts car (same make/model/year) had the same thing - 1 wire going to it. The light under the hood looks the same but works (agree that the parking lights have to be on for the hood light to work). Can't get trunk light to work with or without parking light on.

Is there a mercury switch in the fixture?

1970cs

You mentioned that you had a test light that illuminated! Run a extra wire to the same grouding surface that you used to get a light (known good ground)
and see if that flies.

The deck lid is what is providing the ground so touch the screw and or outside of the socket with improvised ground circuit. I believe that you are correct that it runs off a mecury switch.

Pat

heritageadam

Thanks for the input, I was able to figure it out. The original fixture in my car wasn't working, as well as a poor ground. I replaced it with the one from my parts car & improved the way it is grounded. Works great & shuts off as the trunk is half closed, like it should. Thanks again for the help.