After hours of troubleshooting and tracing wires, I've came to the conclusion that the climate control isn't sending a +12V supply to the a/c pressure switch. This is the early style climate control (1987). Is there a "brain box tucked away in the mess behind the dash? What tells the climate control to send a supply to the pressure switch, is it something as simple as a microswitch on the duct work? It's really got me stumped. Has anyone had a similar problem? All my fuses are in order. Any help mch appreciated. Thanks.

There is an a/c delay relay mounted next to the high speed blower relay on the heater plenum behind the glove box. The delay relay allows power to flow from the control panel to the low pressure switch mounted on the receiver/driver only after the alternator has been charging for approximately 10 seconds or so. Do you have a wiring diagram for the a/c system? Let me know and I might be able to e-mail one to you. John

Thanks for your reply! I don't have a wiring diagram, but, after resoldering and fiddling with some things, I finally got power to go to the low pressure switch. I need to get a pressure gauge now and verify the system's charge state. Thanks for your time and effort!

Hello:

The control box (the one with the dials on it) can develop cold solder joints just like Volvo relays do. This can lead to the failure you are talking about. It can be resoldered quite easily, once you have it out. Alternatively, you can find these controllers in the pick-and-pulls and on e-bay.

There may be more on this in the 700/900FAQ that you can access under FEATURES above...

Good luck!
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Herb Goltz, London, Ontario, Canada '92 245 w/102K mi

I've had the control box out (the one with the dial and lever), however, all it is is a multiposition switch (no soldered anything) and a vacuum selector switch. Is there a seperate "brain box" from this. This is on the older style climate control.....ACC, I think it was made from 83-87. Thanks much.