Yes, I only have part of the wiring harness - the part that goes to the switches. I had to create the wiring to hook the switches' harness to the heating elements.

Here's what I did: I ran the hot wire from the fuse to the blue wire in the switches' harness; a wire from the blue/black harness wire to the driver element's red wire; a wire from the blue/red harness wire to the passenger element's red wire; and the black wires from the harness and both elements to ground. All connectors are insulated.

I identified the color scheme of the switches' harness from the wiring diagram of the 1986 240, the first year that heated seats for both passenger and driver were offered. (In an earlier post I said the harness was from a late 1980s 240, which is wrong.) The color scheme changed in 1987.

When the glass Buss fuse in #4 blew, I put in a plastic Volvo-type fuse of the same amperage and so far it's holding, even with both heating elements on. My Volvo dealer once told me that the Buss fuses are too sensitive.

I have to pull the carpeting anyway to repair some rust holes. I'll look for the original supply wire then...when it gets warmer.
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Mike F - 1984 244 DL - 229,000 miles - with Euro headlights and lots of gauges