Cab light question

[midwest]

Must first say I know zero about electrical, I just don't get it. Anyway last year I had my truck painted. I noticed last night only one of the cab lights was working so I assumed the bulbs were bad as they are pretty old. I pulled the covers off today and the bulbs looked good so I swapped a few into the spot that is working and they worked. The far right spot over the passenger door works the rest are nothing. Seems like every thread I read on here starts with "bad ground". Are the sockets for the marker lights grounded to the roof or is there a ground wire I should be looking for. Any other input is appreciated... Also I don't honestly know if they were working before it went in for paint. At one time they worked but the truck set for a year or so before I took it in to get painted.

 

[mtbadbob]

I believe they are daisy-chained, so the check the feed wire from the one that works to the one next to it that isn't working. Hopefully, that is the culprit and the rest of the lights will work once you get power to that light. You can check power with a 12v lighted stab tester.

 

[midwest]

I just replaced my headliner last month and if I remember the wiring goes up to the pillar and into the cavity in the roof gap. Is there even a way to physically check the wiring? Also the wiring went up the driver side, I assume if they were in series wouldn’t it start on that side and go to passenger side?

 

[75gmck25]

So you have cab lights over the doors? I’ve never seen that setup in any pictures, so it may be aftermarket. AFAIK, the stock interior lighting is a dome light on the back ceiling of the cab, and one or two small lights in the footwell.

The orange wire on the interior lights circuit has constant 12 volt power. The white wire can be grounded through the rotating the headlight switch or by the door switches. This is different than most other devices (headlights, hvac, etc) which are always grounded, but switch the power.

 

[midwest]

I guess I described it wrong. I was just saying the one closest to the passenger door, not above it so to speak. As far as I know they are stock lights in the stock configuration.

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[AKguy]

Ahh, your clearance lights. Those are usually daisy chained for power and ground to each with the wires travelling up the pillar from the ground “bar” above and left of your left knee and from the headlight switch for power.

 

[Termite_Delight]

Those are not factory stock clearance lights, someone added them on.

 

[midwest]

Thanks good to know. I've had the truck for almost 20 years, and based on the guy I bought it from I just assumed they were stock. I've got some friends that are electricians, I'll let them take a look.

 

[75gmck25]

Remind your electrician buddies that the interior light circuit switches the white wire not the orange wire (which would be equivalent to the black wire in a house). That means all powered interior lights must be electrically isolated from ground.

 

[midwest]

Thanks for the input, I appreciate it.

 

[midwest]

Those are not factory stock clearance lights, someone added them on.

I haven’t had time to mess with the lights yet. Curious though, are you saying they are not stick based on the light itself or the location. Just curious if I am likely dealing with factory wiring and aftermarket assemblies or if you can tell based on the location that the wiring and lights are aftermarket, if that makes sense.. Seems to me like a lot of trouble to run wires in that void just to wire up lights if they didn’t come on the truck, but stranger things have been done

 

[Grit dog]

Remind your electrician buddies that the interior light circuit switches the white wire not the orange wire (which would be equivalent to the black wire in a house). That means all powered interior lights must be electrically isolated from ground.

He’s still not talking aboot dome lights.

 

[Craig 85]

Here's the wiring diagram for the roof lights.

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[Craig 85]

Also, factory lights are mounted like this. The two outward lamps diagonal.

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[midwest]

Thanks, the housing and placement of mine to not look the same as yours. Seems like a lot of work to mount marker lights like that with the wiring run the way it is. Is it an add on you guys see very often? If someone had just dropped the headliner and wired it that way I could see, but trying to run the wires in that void seems like a pain just to have marker lights.