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

Not here much as all my Volvos are gone, but saw this and had the same issue with my 93 940.

Take seat out and get the power seat module from underneath, pop the cover and reflow all the solder joints, or alternately, find the 1 or 2 cracked joints and resolder. I just reflowed anything that looked suspicious and bingo it did the trick, the seat worked fine. The memory was still dicey, but it went back and forth and the seatback adjusted fine until I sold it years later.

Mike

Power at the fuse and motor?