I just did a multi-pro swap for my 22 Silverado and it was relatively easy. Luckily all of the wiring and relays were there for the minor gate. For starters I cut the ground wire to the mid gate switch. I needed to get 12V to this. (I know I am talking ground and 12V, but stay with me here...) At the Chassis side of the tailgate harness there is 12V Battery at Pin 1. this was ran for trucks with the power up option. My truck had the fuse and ckt already. So I cut the lead out of the connector and ran a new wire up through the tailgate following the factor harness and connected it to the ground side of the pin on the minor gate switch. The other end of the switch is the yellow lead that goes back to the BCM to signal the button was pressed. Again I happen to have the minor gate relays and wiring on my standard gate LTZ, so I don't know what other trims it was also there. I needed to use this new 12V ckt I made to go direct to the two relays top drop the minor gate. At the BCM I cut the Yellow switch wire (Pin X6-15) and connected it to relay outputs White/Gray (Pin X6-7) and Gray/Blue (Pin X7-7). From the BCM this relay output was power to ground. So by starting my switch at the 12V+ I just created a new ckt though the switch to the relays and down to GND. I did pull the 30A endgate fuse while I was doing all this. It all works! The only downside is when the vehicle is locked, this ckt is still powered and will open upon press. I have the factory up fitter switches too, so I think I will use one of them as a disable possibly. Should be really easy as the BCM is right below the upfitter switches. The multipro I got was the same color truck but a GMC. I still need to swap the emblems. Waiting on a good sunny warm day to make that chore a little easier.
I was able to do a swap to a multipro. Mike
