Securing the Cargo Lamp

[bonfire]

I recently purchased a new cargo lamp for an 86 K10 and it comes with 2 rubber well nuts to secure it to the cab. These rubber well nuts will spin inside and will not grip or get tight. I've tried rubber contact cement but that just breaks free with little turning. Anyone have a better solution for securing the cargo lamp?

I've heard of others using a metal rivnut but since the dome and cargo light have full time power, and are switched on the ground side. By running a metal screw into a metal fastner attached to the metal body, you are giving the light a ground and you won't be able to shut it off at all.

 

[RoryH19]

My factory cargo lamp and dome work from the door sensor. It is always grounded and when the door opens the circuit is completed and + power is provided. There is also a on/off switch on the B pillar but the principle is still the same.
It I recall the base of the cargo lap mounts to the cab with slide on fasteners. Don't recall the exact name but they are used all over the truck in different sizes. Would be similar to the rivnut and provide ground.


Edit:
I just looked at my cargo lamp and it has 2 separate wires for the bulb.
They run through the cab down the pillar.
The base does not provide the ground.

 

[75gmck25]

If the cargo lamp is assembled properly, the mounting screws do not ground the electrical contacts to the body. The electrical contacts for the bulb are insulated from the Lamp housing. I thinks mine just has sheet metal screws, but I’d have to check for sure.

Bruce

 

[HOTFOOT]

Does the nut thread on to bolt or is one sae and one metric? Burr on the threads?

 

[Grit dog]

I'm unsure if the screws grounding to the truck body is bad or not, but could you set the rubber pieces with a little epoxy or JB weld? That would hold better I think.

 

[bonfire]

Yes, my light also has two wires. The info I was finding above was actually in a 67-72 chevy truck forum so that might have been a single wire during those years. I took the well nuts out and held them loosely in a vise to see if they would start to collapse but they did not so they might be just junk hardware and need to buy some quality ones but might be a better idea to just go to a rivnut since it isn't actually used as a ground. Might hold better than the zip ties that are being used now

 

[harcorshe]

Did you get this figured out? The rubber-encased threaded inserts do expand and provide a good connection. Might have them in backwards. (I went through the same thing last year)

 

[bonfire]

Not yet. Still have them zip tied on. I might try to buy some new well nuts as the ones I got from LMC don't crunch or collapse when tightening the screw. Maybe someone makes a metal well nut that not only has inner threads to mount the light but outer threads to put a nut on the inner cab layer. Since there is a big enough hole in the cab to get your hands in, it would be possible to put a nut on the back end if the well nut or nut sert had threads on the outside but my google searches haven't found one yet.