Hi! Thanks for reading my post.

I have a 93 960, and just a few weeks ago I noticed that the clutch for the AC compressor can no longer engage. The "AC Off" light does not blink so there is no error code detected by the control computer. I tried bypassing the compressor control by jumping the wire directly with the battery (14V), then the clutch works fine and the AC blows cold air.

I am guessing there might be a problem with the temperature sensor (since the owner's manual says that the compressor does not engage if the outside temperature is lower than 45F), or the ECC circuit board and/or relay (I read that there could be problems with old solder joints on the circuit board).

My questions: Where is the ECC circuit board/relay located and how can I pull it out? Are these the only place I should check?

Thanks!!

The control computer for the ECC is directly behind the 3 knobs for the AC control. They are all one solid unit. I don't know any other details about the inner workings of the system but here is the 960 dealer service manual in PDF form.
http://caunter.ca/volvo960/
Good luck
Justin

Dear skid,

Good a.m. and may this find you well. The A/C circuit board/relay are in the A/C control unit, which is in the front center console, just above the radio.

I do not own a 960, so do not know how specifically to remove the controller.

Once you've removed it, you'll see that there's a shiny metal cover, secured by four tabs. Undo those tabs and lift the cover. You'll see a circuit board. On it will be at least one rectangular plastic box. That's the relay. It is attached to the board by four pins. Micro-cracks - sometimes far too small to be seen with the unaided eye - in a solder joint can stop the flow of current to/from the relay (in effect, a sealed switch).

To reflow the solder, touch the tip of a 25-watt iron (anything larger might do damage) to each joint for 1-2 seconds. The instant the solder liquefies, remove the iron. The solder will cool almost at once. You've reflowed the joint!! Do this on each of the other three pins.

You should also reflow the solder on the main connector, which is at the rear edge of the circuit board. This connection has, if I recall correctly, 14 pins.

Hope this helps.

Yours faithfully,

spook

Spook,

Thanks for your quick and well-written reply.

I am looking for specific instructions for opening up the dash board and to get to the ECC circuit board -- I have never opened the dash board myself. Can anyone point me in the right direction?

Thanks much!

-Skid

It's a fairly simple operation to get the unit out. A great description is in the FAQ, which you can read by clicking here. It also includes information and pictures for resoldering the cracks in the circuit board.

I had the same issue with my 960. I bought a used control unit, but didn't need it when I resoldered my circuit board to correct the problem. If you later decide you need to replace the unit, send me an email. I still have my extra one available.

Good luck with the repair.

Robert