Hello all, new to the community and glad to be here,
I recently bought an 01 Yukon SLT 5.3l, equipped with 4wd and Onstar. The biggest issue I've had is the parasitic draw. The car draws around 50-90 milliamps at rest, whereas the factory spec is around 25-30 milliamps. The car was stolen back in February of 2020 (and recovered), so the Onstar microphone, and GPS were disabled (the wires cut). I originally thought that the draw must be from the Onstar, but I disassembled the dash and disconnected the VCU and VIU, but I did not notice any change in draw. The only time when the draw dropped to within factory specification was when I pulled the RAP #2 fuse, which supplies power to some other accessories (locks, horn), including the Onstar VIU. I had to reinstall the RAP #2 fuse because the front passenger power window and power sunroof stopped working. I suspect it is with the RAP unit, or the BCM, but I'm having trouble finding exactly where it is drawing from. I should also add that the front passenger lock actuator does not work, and the front drivers side key cylinder is missing. The car also has a DEI remote start system (which is wired to an aftermarket switch for some reason), which does not work (likely because of the broken front passenger lock actuator and missing key cylinder). I know that is a lot of symptoms, but does anyone have any recommendations on what to do? Any tips or help would be appreciated. Thanks in advance!

Get rid of anything NON-OEM and start again.

Agree, disconnect anything non-OEM, especially a remote start system.

My 2001 Yukon XL SLT 4x4 Autoride with over 300,000 miles on it will sit for a month then fire up like it was last run a day ago.