William Sherman

That is my plan as well if I ever need the 5th switch or a 30amp circuit. It should be at pin #8 in the gray plug, GN/BU wire. UI Bulletin #153 has a wire schematic with color coding for each switch/relay.

The fifth wire (relay and switch 5) is in the gray plug and heads up to the third brake light to power a roof beacon.

I just ran my cable to the battery box and connected to the fuse. The secondary fuses that would be part of the snowplow prep kit are also part of the upfitter switch kit.

I did the install myself. It took a couple hours of actual work time. Hardest part was the dash disassembly to install the new knee bolster. Which begins with center console disassembly and working your way back to the cluster and then lastly the bolster. The only part I had to come up while the dash was torn apart were the mounting screws for the fuse block, which added to my over all time; and are not mentioned in any of the parts lists.

You need more than the bolster and switch, you also need the switch harness. Check prior posts in this thread for that part number.

Figuring out how to get the dash apart without breaking something or leaving a mark to install the bolster was the hardest thing about this install. Now who’s figured out how to easily remove the third brake light to gain access to the interior of the spoiler?

After months of waiting for the kit, I fabricated my own cable to the battery. I cut off the OEM battery cable connector plug on the harness connected to the fuse/relay module. Utilized a length of 8awg cable, wire loom, crimp connectors, 30amp fuse at the battery, and zip ties. Utilized the OEM pass through at the firewall. Two months later, still works flawlessly. It’s just a power cable, the only thing fancy are the OEM exclusive connector plugs. Use an alternative 8awg connector or a butt splice connector.

In the kit I got the studs, fuses, connecting power bar , etc.

Sorry for I’ve not been able to come up with the individual component part numbers contained within this kit. Anyone in here at a dealership that can look up the individual components that comprise the kit.

Finally got home to look into my console for the UI Bulletin on blunt cut wire and drilling locations. https://www.gmupfitter.com/files/media/photo/1329/UI Bulletin_157.pdf

The switches are latching switches driving 20 or 30amp fuses. It took a bit to figure it all out. The switches and main battery cable were on a back order the last I knew. But I was told my 2020 Sierra SLT crew cab couldn’t be equipped with the OEM upfitter switches, I’m so looking forward to returning to the dealership and saying look at this, BOOM. lol I’m away from home working on the states response to Coronavirus, I don’t have access to my notes, part numbers, or TB’s used to figure this out. my apologies for delays in responding.

I’m away from home working on the states response to Coronavirus so I can’t get to my notes or the tech and upfitter bulletins I collected. As I recall the bulletin you have to pull the third brake light to access the blunt cut wires for the roof beacon. It also showed the correct location to drill the spoiler. I wouldn’t just drill a 3/4” hole to just root around in there.

That is the 5 switch module. The outputs from the relays associated with switches 1-4 are left blunt cut in the harness. The output from the relay associated with switch 5 is within the vehicle plug and does provide power to the roof beacon circuit(located behind the CHMSL). But that could also be modified by removing the relay output from the vehicle plug. I just installed this stuff this week. The battery cable was still on back order so I constructed my own.

today's message at GM upfitter

I have been waiting on the battery cable (84497098) since early December; have all the other parts to put this in my 2020 Sierra. Even resorted to contacting TE Connectivity to inquire into the availability of the end of the battery cable that connects at the Aux. Fuse Block, not so lucky there either. Frustrating to be this close and yet so far away...