Weird CMM issues Topic is solved

redc70 · Post by **redc70** » 19 Oct 2018, 16:20

Hey all. Wondering if anyone has had this issue or knows what to try next:
1999 C70 Cabrio LPT. 155k miles
Lately, as it has been cooler here (50-60f), the climate control has only been working intermittently. First thing in the am, start the car, and absolutely dead climate control. No lights, nothing works as if someone has pulled the plug. Sometimes I drive about 5 miles and 5 minutes to grab some morning joe, get back in and all is well. All the controls work, ie, fan speed, temp control and the knob for defrost. The floor vents have never worked and I guess that is the damper motor but no worries. If the outside temp is above say 70-75, it turns on and the ac works fine. Drove to work this am and as usual didn't work. After work again, all is well. Here is what I have checked so far:
All fuses under the hood, no issues.
When it does work I perform the self test diags via the recirc button. No stored or pending codes.
Reset the car via unhook the battery and completely discharge the system. Tried the lock unlock trick, and reset the windows.
Hooked it up to VIDA/DICE and ran the entire system. No codes. The CCM module icon came up green as it should.
I've read that the thermister has caused a device to stop completely but not come back on. I have not touched anything on, under or around the dash so I don't think the thermister is broken or bad. But, of course could be.
The next thing I might try is to remove the stereo system, and pop out the CCM head unit and check for broken or frayed wires?
So, if anyone has any input I would surely appreciate any and all help.
Many thanks in advance!

Post by **wizechatmgr** » 19 Oct 2018, 17:17

With VIDA/DICE I'd check the cabin air temp sensor & associated fan as well as the air temp sensor for the air handler (whatever you volvo junkies call it) =)

redc70 · Post by **redc70** » 19 Oct 2018, 17:39

Hi, and thanks. I did look at the values in vida for this module, not a clue really as to what they should be set at. Any ideas?

Post by **wizechatmgr** » 19 Oct 2018, 18:19

Grab a snap shot of the values you're getting for it. I don't have mine in front of me at the moment, but I may see something that looks suspicious.

Do you lose or gain any other dash lights or electrical systems at the same time when this is happening?

redc70 · Post by **redc70** » 19 Oct 2018, 18:29

I'll hook it all up tomorrow and see if I can get some images. No, everything works just fine. Radio, all lights fogs etc. Even the heated seats function. I had been thinking it might be a temp setting somewhere too. Just don't know which ones or what they should be. Also not sure why it worked fine all this VERY hot summer and last years cold winter. Hmm, strange car this!

Post by **wizechatmgr** » 19 Oct 2018, 18:31

Whatever you do in VIDA, don't do a CCM Adaption/Calibration... I've bricked several this way and don't know how to fix them yet. Likely need to remove an eePROM and reprogram it.

redc70 · Post by **redc70** » 19 Oct 2018, 18:43

How about a CCM reset? I have that as an option.

Post by **wizechatmgr** » 19 Oct 2018, 18:44

Unsure. I'd let someone willing to toast theirs be the guinea pig.

I have found the CCMs on Ebay for ~$40-60 before.

redc70 · Post by **redc70** » 19 Oct 2018, 18:59

OK, thanks wizechatmgr

Post by **Clemens** » 20 Oct 2018, 02:02

ig you can source a control unit for cheap, try swapping it. on my 95 NA the fans started avting weird and a used ECC solved the problems.

edit: i don't know if the control unit can simply be swapped on 99s, or if it has to be married to the system