04 XC90 A/C stopped blowing cold after GROM audio install

sikbrik · Post by **sikbrik** » 03 Oct 2018, 19:16

I recently installed a GROM audio unit in place of our CD changer on the 04 XC90, premium audio. Works great and I had done the same upgrade on our 05 previously with no issues but, after this one, the A/C is no longer cold and I can see that the compressor won't even try to engage. The sunroof is also suddenly intermittent. Is this more likely coincidence or are the systems possibly linked together and need programming? I realize after some googling that I didn't have the key in position 2 when reconnecting the battery.

For reference, A/C was previously very cold and never had an issue. It seems oddly timed that it suddenly failed. Same with the roof...always worked fine. Now seems to only rarely work but more often not at all. I've unplugged the battery overnight to no avail but, again, not in position 2 when reconnecting. I've considered hooking the CD changer back up without the Grom to see if there is any change.

2 things I know...i accidentally unscrewed the HVAC module separately from the radio, since the screws are in the same location...didn't unhook anything and put it back but thought I'd mention it. Also, the outside temperature has always been wrong...reads below 0 most of the time. Will that affect HVAC?

Thanks for any tips!

Post by **oragex** » 04 Oct 2018, 02:22

Don't think it's coincidence. Try to lock/unlock the doors three time with the key fob, but not much hope

It may happen on these XC90 the thermistor behind the small grid on the CCM face to blow when the battery is connected/unplugged without the key in POS II. Don't know how to check this, but not impossible the CCM has an issue - just a guess.

The outside temp sensor is located in a side mirror, it may go bad, not sure if it's related or not to the CCM

No worries about tossing the CCM, just don't unplug the module with the battery connected.

sikbrik · Post by **sikbrik** » 07 Oct 2018, 15:53

Fixed the sunroof with the disconnect and reconnect in position 2...but then got careless and unplugged the CCM with battery connected, just as instructed NOT to do haha. So I have an SRS urgent light..mno biggie, I'll reset.

A/C pressure is good...jumped the relay, compressor kicked on fine, cooled off but then overpressured. Swapped the relays so I had a known good relay. A/C won't engage without jumping relay...so I'm blaming CCM. Ordering a cheap eBay vida/dice and will clear codes and recalibrate before I go that route but then I'll swap CCMs between my 04 and 05.

long story short...thanks, sunroof is working!

Post by **oragex** » 07 Oct 2018, 16:36

Keep us updated. For the A/C, the evaporator thermistor can sometimes go bad causing the compressor to run without cycling, building up pressure, and getting the evaporator to basically freeze from too much cooling. But that wouldn't explain why it won't engage in the first place.