‘86 C10 Cargo light confusion. Help!

[BlazerBill]

‘86 C10: I’ve had a very nice, previously restored C10 for about 1 year now and am finally trying to figure out why the cargo lamp would never off (had to resort to removing the bulb). There is no separate cargo light switch and thought it should be operated by turning the dash headlight switch that also operates the dome light. I have constant 12 volts at the 2 wire plug which grounds to the lamp housing/screwed onto cab. Another strange thing is the bulb that I removed was a 2 filament 1157 incandescent bulb which stays illuminated (thus having to remove it). It is my understanding that the correct bulb should be a 1 filament 1142 bulb which I have tried but won’t illuminate at all with confirmed voltage with the plug grounded to the housing/body. I accidentally shorted the wiring which also blew the dome light so I know the dome and cargo light is on the same circuit which also makes me believe that they are both controlled by turning the headlight switch. So, why won’t the incorrect 1157 bulb won’t turn off and the correct 1142 bulb not turn on and why doesn’t the headlight switch operate the cargo light but does operate the dome light? See pics. I’m so confused! Thanks!

 

[Bennyt]

There should be a switch over your left shoulder near the seat belt mount.

 

[geocrasher]

You'll always have 12v. This is normal. The interior lights are switched at the ground. The switches themselves are in the door jambs by the hinges. When you open the door, they pop open and ground the bulb. Simple. One of them is probably damaged. Or both of them.

 

[BlazerBill]

I thought there should be a switch over my shoulder but there is no switch on the panel. So, I removed the panel and Lo and Behold, the wiring was taped to the metal but without a switch. I’ll have to buy a switch and cut a hole in the panel to mount the switch. Thought I was losing my mind. Thanks, BennyT for boosting my confidence! You never know what you may find or don’t find on a previously restored vehicle.

 

[BlazerBill]

Without having the switch, I jumped the two wires, closed the door and now have a properly operating cargo light operated by the the headlight switch. So, I guess I don’t need a separate switch above my shoulder, or do I?

 

[Bennyt]

Without having the switch, I jumped the two wires, closed the door and now have a properly operating cargo light operated by the the headlight switch. So, I guess I don’t need a separate switch above my shoulder, or do I?

Personally, I like a separate switch for multiple reasons:

If you turn on the light and try and look through back glass, you may only get a reflection with the interior lights on.

On some of my other trucks, I swapped out to high powered LED's and use it for an additional reverse lights.

I don't have the cargo light on my C10 but am going to add the LED cargo light/ 3rd brake light from United Pacific on my DRW.

 

[BlazerBill]

So, if I install a separate cargo light switch, how does it work with the headlight switch that also turns the cargo light switch on and off?