Lack of power and overheating on inclines while towing 2000 lb tent trailer with 93 GMC sierra 1500 4x4

Google

year make model fuse box diagram

and

year make model tow package wiring schematic

The GVWR is 9200lbs

sounds like a bad ground on trailer

Disconnect the trailer wiring and recheck the vehicle lighting. If it returns to normal, then obviously the trailer is the problem. Quite often the trailer plug loses its independent ground and it will back feed thru other circuits trying to locate one. Especially if its a boat trailer, water intrusion can cause havoc on the grounds due to corrosion. The under hood electrical center has circuits intentionally meant to be used for trailers. You CANNOT just jumper into the rear lights of the truck (tail, signals and brakes coming from the tail light connector). Because it uses a multi-function switch, the brakes and signals are actually the same circuit, and have to be wired separately for a trailer plug to operate.

Yes.
Regards, David

sounds like a ground problem on the trailer

G'day mate on the plug at the vehicle tow bar is the earth circut from plug hooked to vehicle and getting complete curciut ?

Jimmy doesn't have this, Sierra does and Yukon. If you are towing a trailer put the trans in drive, not overdrive.

tow in tow/haul and use 4x4 when necessary..it is how the truck is designed ..... :) have a good day