1987 300sdl a/c compressor not engaging

[Dallrut]

My wifes 300sdl has had an intermittent problem with the compressor not engaging. It would be working fine until say stopping for fuel and then would not work upon restarting. Finally it stopped working at all and I think it is a good thing. It has allowed me to find the problem but not the cure. I tested the limit switches and they are good. I can unplug the klima relay and jump it to force the compressor to run (250psi on the high side and 40psi on the low side). I then ohmed out the speed sensor on the compressor at 880ohms OUCH!!!!! Just a bit out of spec. I am looking for information to by-pass the speed sensor. PLEASE HELP!!!!!