Accessory install using upfitter switches 2025 3500 L5P

Chris Lungstrass · May 30

Maybe a dumb question but…I installed my GM upfitter switch assembly which was not really too bad. The trim removal is a pain. For clarity, the four blunt cut wires powered by the actual GM switches are simply to open a relay? I still need to get a power supply and grounds separately.

PBNB · May 30

The power comes from the right side battery and feeds the little fuse panel that the buttons plug into.

Did you get all the parts for the kit?

Once it is all connected all 5 buttons will be able to power most accessories. I have my extra fog lights and my dash cam connected so far.

If you are planning a snow plow or something that needs a lot of power, there is another power feed on the right side battery for things like that (I think it is a 200 amp connection).

Chris Lungstrass · May 31

Ya, got the complete package when I bought the truck. I will be installing a small compressor for air bags. So I’ll wire a relay to the Aux switch to turn it on and off. The actual power for the device will be fused and come from live posts where the plow fuse is above the right battery.

PBNB · May 31

You should be able to connect to the leads coming off the fuse panel that came with the kit. You can see that each AUX button has a fuse and relay already. SW 1, 4 and 5 have 25 amp fuses.

SW 5 has the wire going to the 3rd brake light area but you can always intercept the wire at the fuse panel if you don't want to use the pre-wire at the back.