Under hood fuse block

higsy · November 26, 2018

Under the hood in the fuse block there are fuses labelled upfitter. Are these safe to use with an add a fuse... I'm looking for 12v switched and if these fit the bill I'd like to use
.

I'm not great with electronics so I thought I better ask first... these also appear to have relays in the fuse block.
Not sure what rap is exactly and I see alot of people obtaining accessory power inside on the drivers side...
I need the power under the hood.
Hope this makes sense

Mileguru · December 1, 2018

On 11/25/2018 at 7:50 PM, higsy said:

Under the hood in the fuse block there are fuses labelled upfitter. Are these safe to use with an add a fuse... I'm looking for 12v switched and if these fit the bill I'd like to use
.

I'm not great with electronics so I thought I better ask first... these also appear to have relays in the fuse block.
Not sure what rap is exactly and I see alot of people obtaining accessory power inside on the drivers side...
I need the power under the hood.
Hope this makes sense

I haven't done any work with the fuses, so I can't answer this, but I'm highly surprised that no one else has.

I'm certain that if you moved this question to the "2014-2019 Silverado & Sierra Mods" section, you'd get it answered though.

TB2015 · December 17, 2018

Wiring diagram looks like it shows the fuses are on the output side of the upfitter's relays, so no help there without a jumper to bypass where the relay should be, or the Aux switches and install a relay.

But... Depending on the year/model, the whole upfitter's add-on provisions may not actually be wired in the fuse box or to the output harness. Just the sockets in the plastic panel where the relays and fuses should go. Use a bright flashlight to look down into the sockets and see if the little metal tabs are there. Or pull the fuse box and look at the underside, but that is a pain.

Currently in the process of building a waterproof fuse/relay box that I can mount on the second battery tray to support additional lighting and 2-way radio circuits that are not OEM on my 2015.

No telling why GM didn't do a one size fits all electrical system instead of maintaining an inventory of multiple versions of the same fuse box or wiring harness. Would make retrofits a lot easier if everything was plug and play instead of having to rewire and reprogram.

UI Bulletin_110j.pdf