I picked up a heated rear window to update my early (December 1969 build date) Porsche 914. Does anyone know if my car's wiring harness actually contains the wires needed to update this car with a heated rear window?

I know the relay board has a plug-in slot for the heated rear window relay. I also picked up the dash switch assembly for the heated rear window.

There is no wiring schematic for the heated rear window option shown on the early 1970 wiring diagram in the Haynes Workshop Manual. Before I install all new wires for this update, I was wondering if anyone else has updated their early 914 with a heated rear window. My car has the Appearance Group with fog lights, chrome bumpers, and black vinyl sail panels, if that makes any difference in the early wiring harness.

My recollection is the heated rear window harness is a separate harness. I am sure we have members here that have some of those they would part with.

Separate harness required. Also requires relay and fuse in relay board where it plugs into.

The wires are certainly included in 1970 914 6 harnesses and I suspect they are
included in early 4 cyl. harnesses as well.
I'll have a '70 parts car here in a few days and will verify.
Pull your bulkhead upholstery and look for fat brown and green wires about 3'
long. If they are coiled up and taped to the firewall you're all set.
If those are found I'll bet the wires for the switch are behind the dash too.

Every 914 I have owned had a rear window defroster, must have been a West Coast thing. Never used it. Never needed to. People always comment about it, which I could never understand why.

My interior light finally disintegrated. This is what was behind it. Factory -6, 3/70.

Click to view attachment

The /6 chassis harnesses include the rear window defroster circuits, the /4s do not and require a separate harness. I have that harness available if needed.