Targa Dome Light Issue - A bit Different

[KerryM]

I read a bunch of threads of door grounding issues; my issue is I am not getting any light in any switch position on my '78 Targa.

Bentley shows that the hot wire goes from the glove box to the dome light. My glove box light works as designed. I do not get continuity from the black glove box wire to the dome light black wire. Am I correct that I should?

It looks like I need to trace this wire and find the break. Where does this wire run? I have speaker wire and a black sheathed wire bundle under the carpet on the passenger side; is this it?

Thanks for all your advice!

Kerry

[garment]

Sub'd, I have same issue on my '83.

[gazzerr]

I haven't had a dome light issue but when I was chasing breaks on my '82 SC it was usually an issue where someone had done a bad repair in the run, an abrasion in the wire insulation causing a short or the problem was actually at one end. It might be just an issue with the bulb holder itself where the wire terminates. Does it have a good ground connection? It could be the door switch like you said. Those definitely wear out and are easy to replace. You just have to careful not to lose the wire at the back of the switch into the door post. A "PowerProbe" (great tool) works fantastic for isolating the problem.

[universeman]

Light fixture could be bad also. Recommend you test with a signal light also directly from the leads on the switch. Use bench power or known 12v. Mine was bad and needed replacement.

[steely]

+1 on the fixture.

If you do find that the fixture terminations are suspect, be careful if the hot wire turns out to be good, so that it doesn't get away from you and touch the chassis.

how is your luggage compartment light and clock? According to a schematic for an '82, the black wire should be hot, and should be continuous to the glove box, clock and frunk. I do not know how they are connected (via a connector or hardwired). Do your best in tracing the wire, or perhaps PM timmy2. He makes harnesses and might be willing to assist with routing info. The door switches only provide a ground path, so if you don't have +12 at the light fixture, they won't matter.

[DRACO A5OG]

swap your glove box light to the targa dome to verify condition of the fixture

[KerryM]

Success!!!

Just in case it may help someone else, here is what I did.....

Checked the glove box light....worked fine
Checked the frunk light....worked fine
Clock works fine
Checked the black (hot) lead at the dome fixture switch.....no power
Checked the continuity of the black dome lead to the glove box.....no continuity
Swapped the dome and glove box fixtures....accidentally touched glove box hot lead to metal and blew fuse (OK, twice)
Replaced fuse and tried again.....dome fixture worked in glove box
Started tracing wires at frunk light....noticed a couple of random taped off wires in the frunk corner by the light that I thought were part of a removed AC
Tested the continuity of a random black wire to the hot lead at the dome fixture.....continuity!!
Noticed a pigtail(?) connection coming off the frunk fixture....tested hot.
Connected the random black wire to the pigtail.....now dome wire tested hot
Connected dome fixture.....now functions as designed so door grounds are also working

I'm still a bit of a multimeter noob, but knowing the simple way to check voltage and continuity is a big deal with these old cars.

Thanks to all who responded for pointing me in the right direction. In the overall scheme of things dome lights are pretty minor, but this had been bugging me since I started restoring the car.

[gazzerr]

Awesome! Yeah it's always someone that's been mucking about in there. I found twisted and just taped wires (!), scotch blocks and even a couple of household wire taps. Geez.

I crimped on proper factory spade connections and then heat shrunk all the connection points so there is no way they can come apart and touch the chassis. The frunk light is classic one. Be sure to isolate that one with heatshrink and add a fuse to the dash lighting circuit.

The other day I even found a relay zip tied under the front smile with one wire hanging out of it. Still trying to figure out what's going on there ...

[DRACO A5OG]

Congrats, now go drive her, She will be happier moving the oil around

[steely]

cool - nice work and thanks for the follow-up.
electrics fool the best of us sometimes.