Bought a 93 940 wagon with dual power seats, neither of which worked. My son noticed that the fuse was missing from the fuse slot. We installed the fuse, but no joy. Instead, about every 10 seconds the driver seat back motor activated for a micro-second. The seat back was already back too far, so I pulled the fuse again.

It turns out the passenger seat wire pigtail was not even plugged in, so I suspect that explains why the passenger power seat does not work.

While looking for problems on the driver seat, I noticed that the wiring harness from the switch bank to the seat motor was caught between the seat frame and toothed seat track. The harness was visibly damaged.

Both front seats had been recovered by the former owner, and I suppose the detail of preventing this problem was overlooked.

Once I extracted the switch bank and wire pigtail, I found that insulation on the tiny wires had been chewed off, and 3 wires were completely cut. It took some fine detail work to repair the damaged wiring harness, but the driver's power seat now works!
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94 940 n/a 320k+ and rolling, owned 18 yrs; 05 XC90 2.5t for the wife; sold 92 745T; sold 88 764T