So I'm new here and to the diesel market. Bought a 1991.5 w250 cummins 4 months ago and have had electrical nightmares. My wiper motor is now turning the wrong way after replacing PCM, alternator rebuild, 2 voltage regulators...etc. what would cause the motor to run backwards, I checked and believe its the correct replacement motor (oh yeah, had to replace that also), cardone 40-388. Any ideas would be great.
BTW I love the pulling power of this truck, towed my 1st load of hay today.....never knew it was back there.
Thanks in advance!

 

Might need a new switch and/or other parts.

 

Thanks Bladeyamaha.

 

Polarity could be reversed on the motor too, I would take it out and do some testing.

 

They might have gave you one for the wrong side. Though if I remember right the whole units won't interchange from side to side. try switching the wires around n see if that does it?

 

If you rewired you might have given yourself problems too.

 

Thanks! I'm going to re-wire this week and see if that helps.