85 300sd tach a/c problems
 

Hey guys I could use some direction so TIA for any and all input,i am trying to get 12v power to compressor clutch,none.Did a search and found a/c will not work if tach doesnt .Well tach does not work,it does not have the amplifier,I did check the over voltage relay,and it is working as well as the OV fuse.I pulled the Klima relay(and it has been apart y someone before )if I jumper pins 5 and 7 I do get 12v to the compressr clutch.So where I am stuck at is this,if the klima realy is bad will this cause a tach to not work ?,or is the tach signal something that actually is used by the klima relay to close the second set of contacts in the Klima relay to send 12v pins 5 and 7 ?

I suggest that if you float your question over in the Diesel Discussion area, you're likely to get more of a response.

BTW, your '85 uses a different tach arrangement than what some of the earlier models used; there won't be a "tach amp" under the hood.

If I recall, the '85s have a small box under the driver footwell that operates the EGR and Tach. At least mine does. :D

The Klima is under the fuse panel on the '85, '86+ is against the firewall.