Rear window defroster

[85MercPark]

When I bought my wagon it had the rear window defroster lines in the window. But there was no switch on the control panel. Bought one from eBay and installed, but no workie. Could it be the wiring is incomplete? The plug was there to plug the switch into.

Now they sent me another, but it is from a differnet year and have to check if it will plug in at all.

Anyone know how that wiring works?

[Paul_]

i've never had the rear glass on a wagon out, so i don't know what exactly it looks like behind the panel, but there might be something unplugged in the tailgate that you have to plug in

[85MercPark]

There are some pretty heavy duty wires running into the tailgate. Could be for the window. Have to check for power at the switch and see if it is bad

[gadget73]

Is there a fuse for it that might not be present? You'd also want to check for power at the rear glass itself.

[85MercPark]

From what I see in my electric manual it has a fuse link somewhere, have to check it.

[85crownHPP]

The rear defrost has its own fuse link coming off of the starter solenoid, its a big yeallow wire and should be in a bundle with 2 other yellow wires.
if its setup like my 85 vic, it will be the one with the 16ga black fuse link.
I was about to tell you where the connctor for the defrost is in the trunk, but then I remembered you have a wagon!

Im having trouble with my defrost myself... Im hoping its just the switch, becuase you have to fiddle with it a bit to get it to come on and stay on, and sometimes it shuts off before its done.
Any tips to replace it?