I am trying to get a bug out of the rear window defroster. It blows fuse 8 when it switches on. I have replaced the switch and that wasn't it. I checked for wire kinks at the wire bundle at the door and checked where the wire connects to the window and all look good.

The wiring diagram shows fuse 8 (30 amp) feeds to a relay (R138) but I cant seem to find it. I thought maybe the relay was shorting. Can somebody clarify the R138 location or suggest other places to look? Thaks all.

 

the d2 electrical library shows fuses 8 and 29 (passenger compartment) as being for the heated rear window, and it does not have an entry for a relay 138. there are multiple references to the "heated rear window relay" but it never states which relay it is. it does mention that there is internal circuitry within the "intelligent driver module" that is switched according to the button state so your problem could be in that mess somewhere.

 

I had this happen with a HRW and it turned out to be a short in the Mirror Heater (all on the same circuit).
You can also check the Fusible Links.