Hi propla7049,
First of all, the hot skin is very dangerous. You need to correct that immediately. TURN OFF THE PEDESTAL CIRCUIT BREAKER AND DISCONNECT POWER TO THE TRAILER IMMEDIATELY.
You may have 2 problems contributing to the hot skin.
First, there's a problem with the trailer grounding. Usually there's a problem with the ground pin going back to the power pedestal being damaged. There could also be a problem with the pedestal. If you're using an adapter or extension cord, they are also likely trouble spots. The ground path is compromised somewhere.
The second problem is that something in the trailer is leaking voltage to ground or is shorted. This might have been going on unnoticed for a while until the ground path was compromised. When something is leaking voltage, the current takes the path of least resistance, which in a properly function system is the ground wire back to the pedestal. When the ground path is compromised, the current will take the a path through the body/skin of the trailer, and ultimately through your body to earth ground when you touch the trailer.
Check for damage to power cords, extension cords, adapters. If none is found, you'll have to have a licensed electrician check the pedestal.
Once the problem with the ground path is found, you can proceed to investigate the problem with leaking current. One possible trouble spot is the electric heating element of the water heater. If the anode rod is not maintained, the heating element can degrade leading to current leakage.
For more information on hot skin, check out the
No Shock Zone website.
After you've resolved the hot skin condition, you can resume work on the slide motor power.
If you have a momentary push rocker switch to operate the slide, where you push one way to open and the other way to close, I think you should find both hot and ground at the switch. The wiring might look something like the diagram below.
