Cargo Light

[HotWheelsBurban]

I have a 96 GMC CCLB

Cargo Light Switch on the dash is 4 Prong

2 Pins to the left of the Plug that are on top of eachother are POWER
2 Pins on the left of each other are ground I assume b/c no power reading

I tried jumping them with no luck and I ended up blowing the Courtesy Light Fuse In the cab

My Brake Lights Work...Cargo Not. I got the truck this way...I installed a LED 3rd Brake light

Does anyone have any photos? Are you cutting and splicing at the PLUG for the 3rd brake light?
OR
Map Lights on the inside? I have a CC so there is one in the front and one in the rear

If needed I can upload a video to my youtube channel to my poor electrical diag

My truck is a 97 but probably identical to yours in this respect. I looked up the operation of the cargo light in the owners manual, and basically what it says is that the cargo light will not function unless the dome lights are active (i.e. the dome override button is not pushed in AKA "off") and a door is open. So apparently it is wired into the dome light circuit somewhere.... When the switch is "on", it's angled towards the top of the dashboard. "Off" is straight up and down. There's a small light in the switch too.
On my truck the passenger side front door pin switch is wonky; it doesn't always stay on, sometimes needs a gentle touch to make it come on.
My truck also has a black plastic bedliner, and I can assure you, that is like a cave at night. Anything dark colored you put back there disappears....

 

[ForeverFalcon40]

My truck is a 97 but probably identical to yours in this respect. I looked up the operation of the cargo light in the owners manual, and basically what it says is that the cargo light will not function unless the dome lights are active (i.e. the dome override button is not pushed in AKA "off") and a door is open. So apparently it is wired into the dome light circuit somewhere.... When the switch is "on", it's angled towards the top of the dashboard. "Off" is straight up and down. There's a small light in the switch too.
On my truck the passenger side front door pin switch is wonky; it doesn't always stay on, sometimes needs a gentle touch to make it come on.
My truck also has a black plastic bedliner, and I can assure you, that is like a cave at night. Anything dark colored you put back there disappears....

One project at a time LOL!

Thanks for chiming in...I tried various combos and nothing worked. It never worked since I got the truck years ago. Since my tooling and knowledge is getting better as I tackle other projects on the truck, I'm coming back to details like this.

Side Note: My Truck has a Cig Lighter port in the bed. My plan was to get that working and install bed light underneath the rails and have it powered by the Cig Lighter Port. I also have a winch inside my bed, that is powered by a seperate fuse box I installed in the cab under the rear seats. I have 5 more open fuses, I can always wire it to that and have a switch to turn them on and off.

If I ever figure this out I will come back here!

 

[HotWheelsBurban]

One project at a time LOL!

Thanks for chiming in...I tried various combos and nothing worked. It never worked since I got the truck years ago. Since my tooling and knowledge is getting better as I tackle other projects on the truck, I'm coming back to details like this.

Side Note: My Truck has a Cig Lighter port in the bed. My plan was to get that working and install bed light underneath the rails and have it powered by the Cig Lighter Port. I also have a winch inside my bed, that is powered by a seperate fuse box I installed in the cab under the rear seats. I have 5 more open fuses, I can always wire it to that and have a switch to turn them on and off.

If I ever figure this out I will come back here!

I'd like to have some bed lights under the rails like you're talking about. At some point the bedliner is coming out (temporarily at least) so I can see what condition the bed under it, particularly the floor, is in. This truck was a farm truck and probably slept outside most of its life. I'm also looking at a camper shell, the yard I frequent has one on a '96 that's the same color (or close enough). Just gotta get a buddy of mine to be off the same weekend as me so we can go fetch it.(waiting on a sale day at the yard too lol.) I was told the original tailgate was stolen, and it was replaced with a freeflow gate. Those are good for seeing who's behind you too!

 

[benvfr]

Some good info in here, I have a tough time with wiring and reading schematics. Trying to take it slow and learn. I am trying to do something similar, by using that Cargo Light switch for another purpose, for some ditch lights. I was hoping there was a relay under the hood that I could just tap in to and be able to use the Cargo Light switch to turn them on/off, but it looks to me like all the wiring is from the dash fuse panel and back. Can I tap into a wire on the switch itself and pull through firewall, then just grab power under the hood for the LED's?