GMC Repair: 2004 gmc yukon denali electrical problem, gmc yukon denali, 2004 gmc yukon

Question
I have a 2004 gmc yukon denali stock.  When i purchased the vehicle used the rear wiper motor didnt work, so i bought a new one and installed it, now its works and has worked for almost one year.  Then it stopped all of a sudden, purchased a new again and when i installed it, it would not work at all.  Checked to see if getting power to the plug, which it was.  Tried running a new ground to the motor, still nothing.  Gave up for the night.  The next day left for work and it came on all by itself.  Now it works very intermittingly, when it doesnt work you can hear a clicking noise coming from it.  I have also noticed the battery light staying on, on the dash after the vehicle is turned off.  And now most recently when the wiper stops working and i turn off the truck, the radio will stay on until the the motor stops clicking.  So i am assuming a bad ground???  i dont see an actual ground on the rear hatch or is it the hinges that are used to ground it? Dont even know where to start.  Any help would be greatly appreciated.

Answer
Hi
This system uses 2 grounds G100 and G410.
G100 is located in the front on the drivers side frame rail where the lower radiator mounting point is
The second ground, G410, is located right side, rear D pillar, which is the rear body pillar close to the hatch opening. It is located indeu the trim piece where the rear most back speaker is located.
Personally, I would check the wiring going TO the rear hatch, especially where it passes through from the truck to the hatch. That area is prone to corrosion and the individual wires getting pinched and frayed.
I hope this helps