That's right. When you reverse it, if the SR runs in the opposite direction, then it's deffinately the switch. If not, it could be the motor itself, though I've never heard of a DC reversible brushed motor to fail in only one direction.

That's a good test that I didn't think of. I have the equipment here to diffinitively make a judgement about the failure quickly, but in a different and more complicated way that would be very difficult to reproduce with a simple multi-meter.

OK, if you have 12V to each contact, then that's half of the circuit. Now see if you can test for a good ground in that same wire. With the switch engaged in one direction, test the other contact (the opposite one that reads 12V at that setting) and make sure that it produced a good vehicular ground. This can be tested by setting your meter to test for resistance. It should read either 0 ohms, or at the worst, 1 or two. Reverse the switch and check the other contact similarly (again, the other wire that does not read 12V in that setting). At least, they should read the same resistance. If not, then again the switch is the culprit. If you have an analog meter, make sure that it's properly zeroed/calibrated first. Remember, becase this is a closed loop system, you have to have a good positive and ground wire to get the motor to run. The switch changes both the ground and positive between the contacts to make the motor reversible. I'd still put my money on the switch.

ATLD

Let me know the results.