Advice Please:my door lock fuse continuously blows

[Havoc]

About two weeks ago I noticed the following:
1. My door lock fuse AND my rear window defroster fuse were both blown. Therefore the manual door lock switches in the cabin do not work.
2. After replacing these fuses, both my locks and rear window defroster worked.
3. Then, after driving the vehicle for a few hours and then starting the car the next day, my fuses were blown again.
4. I changed the fuses twice now and don't know what is causing the problem.

I think this may be caused by short somewhere. I do not know where. The fuses only blow after I have driven vehicle for a few hours.

Does anyone have any advice on how to fix this problem. Thank you.

 

[TheDurk]

About two weeks ago I noticed the following:
1. My door lock fuse AND my rear window defroster fuse were both blown. Therefore the manual door lock switches in the cabin do not work.
2. After replacing these fuses, both my locks and rear window defroster worked.
3. Then, after driving the vehicle for a few hours and then starting the car the next day, my fuses were blown again.
4. I changed the fuses twice now and don't know what is causing the problem.

I think this may be caused by short somewhere. I do not know where. The fuses only blow after I have driven vehicle for a few hours.

Does anyone have any advice on how to fix this problem. Thank you.

First suspect is the harness between the liftgate and the body. The solid blue wire in there is a tap off the 30A POWER Fuse (aka door lock fuse) and the solid black is from the DEFOG fuse. The blue is powered full-time but the black is powered only when rear defrost is used. Were you using it? I hope so, because if not I have no idea how that fuse could blow. The relay is on the other side of the fuse.