heat and a/c running at the same time?

deltajets · Post by **deltajets** » 03 Oct 2011, 08:03

I have a 98 v70xc.Over the summer from time to time if the a/c was on half the upper dash vents would start to blow heat.If I shut it off and on then everything would return to normal.now it blows heat all the time but only on the drivers side.I did a search of the archives and saw two identical problems but with no solutions or suggestions.I was wondering if anybody knows if this is a control problem or a broken door in the mix chamber.I have the auto climate control but there are no lights flashing so I guess no faults?I'm going out for a run then home to take apart my dash in hopes of finding the problem.Any suggestiions would be welcomed.Thank you.

Ndavis9743 · Post by **Ndavis9743** » 14 Dec 2015, 14:25

Same problem here but now climate control, radio and dash lights are completely off but everything else works. I guess the speakers were out before except the two in dash. Any solutions?

Post by **scot850** » 14 Dec 2015, 14:43

For delta jets, it sounds like you may have one or more servo motors not working, there may be an ECC control issue, and possibly the cabin temp controller.

First, remove the cabin temp controller from the dash and clean it carefully. These can fail, but often just need air-borne crud removed from the unit and the little fan to get it working correctly.

Second, check that the cold air flap has not jammed or the control arm from the motor has broken. There is a recent thread I wrote on for that.

Finally, if all else is now checked and ok, it may be the ECC unit failing or the ECC servo motor (high up on the dash on RH side of the steering wheel behind the dash.

Lastly, it could be the A/C compressor clutch needs adjustment. Again many threads on this using zip-ties or bread bag clips to shim the clutch.

For the second requester, I'm not sure what may be the cause. First I'd check all the fuses for these items are good. The bulbs do fail, and can be time consuming to replace. There are repair how-to's here someplace just search them out. I'd also check the wiring to the back of both the ECC unit and radio are clean and fully pushed into their sockets to start.

Neil.

Ndavis9743 · Post by **Ndavis9743** » 15 Dec 2015, 10:46

For me it was the wrong size fuse (30) in the radio slot (10). But now half the stereo lights are out and the only speakers working are two tweeters in dash.

Post by **scot850** » 15 Dec 2015, 23:05

The lights in the radio can and do burn out with age. There is a how to on replacing the internal bulbs. Not really difficult, just takes time and patience. As for the speakers, what radio do you have in your car? Do you have a Volvo radio and separate amp?

The speakers in the doors may have popped, and the wires that run to the doors can break with age, but it is unusual for both to fail at the same time. It may be worth a trip to a junkyard to pull even one door speaker to check if it fixes that issue. You could use it in both doors to check them out.

Neil.