My son's 1992 940 suffered from classic failing speedometer due to rotting capacitors inside the unit. We tried replacing the caps but that failed shortly thereafter. I reviewed the various approaches in the FAQ to fixing the unit, to wit:
1. Use a 1993-1994 cluster but move the 1992 fuel gauge and PCB capacitor to the replacement cluster. This requires soldering the flex board and drilling some holes to fit the earlier gauge in the later cluster.
2. Replace both the cluster and the fuel sending unit so that the gauge matches the resistance of the latter.

We opted for the latter. We bought a used 1993 cluster and a fuel sending unit from a yard. We replaced the in-tank pump with a new pump, hose and filter sock for reliability. We cleaned up the cluster PCB with DeOxIt under the cadmium screws which were showing a little oxidation after some years on the shelf. And we installed the whole works. As usual, the fuel unit was a little tricky to maneuver in place (made worse by doing it in the street in Boston). And in the bright sunlight it was impossible to see if the panel lamps worked. But in the end, it all worked just fine. Total cost was $110 for the used parts and another $125 or so for the pump, hose and filter sock. This car is in perfect condition and it would have been a tragedy to discard it over a couple of failing capacitors.

If you do the swap, try to keep model years congruent. And remember that 91-92 cars have the failing speedometers; 93-94 clusters and fuel tank units will swap in; 1995 will definitely not work in earlier cars. See the FAQ for detailed instructions.
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See the 700/900 "FAQ" at the menu bar top screen left side.