I am still tracking down the problem with my "91 B350 van (no speed reading and won't shift into overdrive) and I need a way to test the speed sensors.

1. Thevehicle speed sensor (VSS):
Testing the contacts with an ohmeterreads infinite resistance (open).
I ran it at 1700 rpm but got 0 volts output. Is this a telling result for this unit?
2. I notice that there is a metal plate underneath the VSS unit that is part of thetranny case that can rotate and be locked into 4 different positions; what is the relationship between this and the performance of the sensor?
Someone suggested"it is adjustable by rotating until the speedo starts working". Do they mean simply rotating that plate? If so, since it was working fine previously with the plate in its current position, would rotating theplate make a difference with the existing sensor?
3. The rear speed sensoralso reads inifinite (open) resitance and its magnet sticks down about 1/16-inch belowis blackplatic housing. Does this sound normal?

Thanks!

 

Well if you cant get a OBD1 scanner its gona be harder to pin point. If there are no readings on the gauges that means the senors are not making a magnetic field so they are probably bad.or something in the gauges are bad also.