tbran
Guest
If your eng. speed picks up from the alt. your problem is the alt. probably. To test it out replace one sending unit for your ,say fan speed, check the wire to your tach switch get this working, then take the wire off the alt. and connect to wire from fan switch and see if tach reads up scale. If so problem is alt. If not it is wire. Switch can be check out in same way. Other speed functions:It has been our experience 90% of time it is sending units; usually wire breaks right at plasticmoulding. Sometimes you can resolder sometimes not. Send unit n is 71357406. Finally mice are the n1 culprit. Check harnesses for rodent damage and place moth balls in combineduring off season. Really helps deter the critters.Do you know what moth balls smell likeIJ If so how did you get your nose between their little legsIJ HA HA joke I couldn't pass up.. Good luck...tbran