74 K10 Dome Light Issue

[Karnage]

Hi there, I recently got me a 1974 K10 and have been enjoying myself quite a bit since then. Like most older vehicles, it has a few things here and there that needs to be fixed. But overall, it's in good condition and I got it for a good price. The last owner before me mentioned that the dome light does not have a bulb and he never tried to get a new one since there is still a light under the dash that comes on when you open the doors. I went to an auto store a few days ago and figured out what kind of bulb I needed. Apparently the owner before the last owner changed it so it took a different bulb from what the auto store found as the "dome light". The bulb that it does take looks like this:

http://tweetys.com/images/products/detail/90bulb.jpg

I checked the wire to the dome light and saw no issues with it. If anything, it's a fuse. But before I start replacing fuses, is there a way to turn on the dome light without opening your doors? There is a way to turn on the light that is on the bottom of the dash and I would think the dome light would come on the same way, but it doesn't. I don't have any issues with the dome light not coming on when I open the doors, as I said, there is already a light that comes on under the dash. I just want a working dome light when I really really need to see inside my cab. I would appreciate some help!

[Prong]

If you turn your headlight switch all the way to the left, your dome and floor light should come on. If you're not getting power to the dome light, check the wiring that runs from there for any breaks or grounding out--it should run along down the driver's side sill plate under the carpet. IIRC, it's an orange or orange/white stripe wire.

[kris's66lwb]

one is orange and the other is orange with a white stripe it runs down the dr side sill under the plate and carpet and up the b pillar and up to th elight unless yopu have a cargo lamp idk if 74 had this poption but there will be a switch on the trim pillar for cargo the wire will plu in there and then out the other die and keep going to slpit poer off to ther cargo light

[Karnage]

Thanks for the replies you two. Welp, seems I'm having some issues with the light then. By turning the light switch to the left, I just get my dash/floor lights to turn on but not the dome. As for the wire, It looks like it is in good condition but I'll check it again. I also tried another bulb, even tho the one I just got was new. Still not going on.

[79gmcc15]

Does your horn work? Its on the same circuit. My dome light was fried inside the socket and was shorting out the wiring and frying my wires. I fixed it by replacing the socket. Low and behold light AND horn worked. lol
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[bigblktrk]

There is power up to the light at all times. The door switches actually complete the circuit to ground. The wires usually get corroded and break under the door sill. Check to see if there is power at the light, do not read across the light check each side to the chassis ground. Then check to see if the ground circuit is complete by placing your tester lead on +12v batt and check each pin. If the tester light comes on with one and not the other you should be able to tell if it is the ground wire or the the +power wire that is open. If neither test lights the tester then the wire is broke somewhere.
Hope this helps.

[tucsonjwt]

I suspect bulb socket at the dome light also. Remove the lens and the lamp holder and look at the back of the pigtail. You can use a cheap DC tester with a light for 12V - jab the wire behind the bulb socket and touch/clamp the other end to the tester to ground. If it lights up you have a bad pigtail/bulb socket. You need a little skill to jab into the wire - need to hold the wire against a solid surface when you are jabbing, and get a good ground, or you will get a false reading from the test light. If you really have no power going to the bulb socket you can follow the wire as described down the door rear pillar, under the rocker trim/carpet, to the fuse box. If you are going to change the bulb socket, disconnect the battery before working on it.

[Karnage]

Originally Posted by 79gmcc15

Does your horn work? Its on the same circuit. My dome light was fried inside the socket and was shorting out the wiring and frying my wires. I fixed it by replacing the socket. Low and behold light AND horn worked. lol
Posted via Mobile Device

Well I never used or tried my horn before, turns out it is not working like you said. Guess I know what I need to replace now. I just hope it works. Thanks for the help.

[79gmcc15]

I would check out your wiring from the light back as far as you can get. I got lucky, but my wiring was getting REALLY HOT! Too hot to touch when I put in fuses to test things out. so check it over real good.