Help w/‘71 Interior Dome Light (1 Viewer)

smokeater

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I was hoping someone can assist me in diagnosing the issue I’m having with my dome light. I removed the dome light while my top was being repaired. I thought I’d restore the light while I was at it and just got around to doing so. I painted both brackets and I re-soldered the two RG wires on the short pigtail-one to each end of the bulb retainer. The middle extension then has a R wire and a short WB wire (with flat round connector ). I attached the WB to the back of the small bolt that attaches small bulb bracket to mounting bracket. The longer red wire then plugs into the wire that comes up through the windshield grommet.

With the bracket uninstalled, I checked continuity on the dbl connection and it was over 2 ...on my meter. Without the bulb in and electrical connections made, I was getting 12v at the retainers when I pulled the light switch.

I partially installed the bracket and installed the bulb. I pulled the switch and no light, though I did see a bit of solder melt and run!! Figuring that the bracket wasn’t well grounded I fully attached the bracket using both bolts.
I pulled the bulb it looked to be still intact as did the soldered ends. I noted after assessing the occurance that the 20A light fuse burned up. I put another 20a in and tried again and the fuse burned again.

This was about as much as I got into it because I didn’t have anymore fuses to replace.

Any ideas or suggestions? Is that WB wire supposed to be attached to the bracket?

Many thanks,
 

73FJ40

After another night of rust removal!
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Melting solder isn't a sign of a poor ground! You need to educate yourself on electric circuits!

You have a short circuit, probably from your soldering job on the positive wire to the bulb contact.

The short could also be in the positive wire near the light, if it got hot enough to melt solder.

Don't start your truck on 🔥 or destroy the wiring harness behind the dash! You should be glad you ran out of fuses!
 
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smokeater

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Melting solder isn't a sign of a poor ground! You need to educate yourself on electric circuits!

You have a short circuit, probably from your soldering job on the positive wire to the bulb contact.

The short could also be in the positive wire near the light, if it got hot enough to melt solder.

Don't start your truck on 🔥 or destroy the wiring harness behind the dash! You should be glad you ran out of fuses!

73FJ40-

10-4 big man, thanks for the advice/constructive criticism, it would be s***ty to destroy my new harness. I'll probably have someone I trust take a look at my work and ensure that its up to standards.

While I got you, do you have knowledge as to how the light is wired? I'd like to confirm that the WB runs to the fastener attaching the bulb bracket to the light bracket.

Thanks,

Smokeater
 

smokeater

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So I did some digging and found an old thread that Coolerman was involved with. He posted a picture of the dome light which I have attached below. My bulb bracket no longer has the rubber gasket as in this picture. Is it possible that this rubber gasket insulates the bulb bracket and mounting bracket? Aside from the possibility of a short caused by a cold/bad solder, could the absence of this gasket also hinder the functionality of the lamp?

Dome light.jpg
 

73FJ40

After another night of rust removal!
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@smokeater

I'd really hate to see you live up to your moniker.
73FJ40-

10-4 big man, thanks for the advice/constructive criticism, it would be s***ty to destroy my new harness. I'll probably have someone I trust take a look at my work and ensure that its up to standards.

While I got you, do you have knowledge as to how the light is wired? I'd like to confirm that the WB runs to the fastener attaching the bulb bracket to the light bracket.

Thanks,

Smokeater
So I did some digging and found an old thread that Coolerman was involved with. He posted a picture of the dome light which I have attached below. My bulb bracket no longer has the rubber gasket as in this picture. Is it possible that this rubber gasket insulates the bulb bracket and mounting bracket? Aside from the possibility of a short caused by a cold/bad solder, could the absence of this gasket also hinder the functionality of the lamp?

View attachment 2061799
The rubber gasket is primarily meant to keep moisture out of the light fixture.

Yes, the white/black wire is meant to go to ground, to complete the 12V circuit for the light.

Since you have a volt ohm meter, with the bulb removed, you should check for resistance between the metal frame of the light fixture and the positive wire of the feed to the light. There should be infinite resistance. Anything else signifies a short between the grounded side of the light fixture and the power supply.

I hope this helps.
 
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Spot on @73FJ40 !!

@smokeater, plz watch a lot more YouTube diy videos. Especially any on basic electronics.

I melted my harness, thru my own stupidity and lack of attention... you don’t want that experience... or, the subsequent melting of your :censor: bowels. :frown:

When a fuse pops, you have a potential problem... when a second fuse pops on the same circuit, you have a potential catastrophe... not a defective or worn out fuse.
 

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