1999 V70 Full heat only on drivers side , manual climate control MCC

readallthebooks · Post by **readallthebooks** » 22 Oct 2017, 16:28

was driving home on the freeway with the A/C on and out of the blue the driver's side vents went to full blast heat. the passenger side is fine. i tried rotating the drivers side temp dial back and forth maybe 20 times and it's still full heat only. shut the climate control on and off again a few times and i disconnected the battery and crossed the terminals for a minute and that didn't reset anything to make it work. what's the next step in troubleshooting?

note: manual control version

Post by **scot850** » 22 Oct 2017, 16:40

If it was an 850 I'd say it was the cabin temp sensor, but the V/S/C 70's only use one for both sides. There are no reasons I can think of where the RHS is not connected in some way to the drivers side. The flaps are all connected. As the temp is the only issue I would suggest the most likely issue is the ECC unit has failed. They are usually sharp enough at a junkyard and simple to swap out. Wear gloves to remove the ECC unit as there are some sharp edges in there. I find wiggling the unit up and down helps to release it from the dash.

Neil.

readallthebooks · Post by **readallthebooks** » 22 Oct 2017, 17:08

thanks. i should note this is the manual control version. if i found the automatic version in the junkyard would that swap in as a direct replacement or no?

Post by **misha** » 22 Oct 2017, 17:20

No.
Mcc & Ecc are NOT interchangeable.

readallthebooks · Post by **readallthebooks** » 22 Oct 2017, 17:32

Uch, bummer. looks like the mcc version is a needle in a haystack

Post by **wizechatmgr** » 22 Oct 2017, 18:43

scot850 wrote: ↑22 Oct 2017, 16:40 If it was an 850 I'd say it was the cabin temp sensor, but the V/S/C 70's only use one for both sides. There are no reasons I can think of where the RHS is not connected in some way to the drivers side. The flaps are all connected. As the temp is the only issue I would suggest the most likely issue is the ECC unit has failed. They are usually sharp enough at a junkyard and simple to swap out. Wear gloves to remove the ECC unit as there are some sharp edges in there. I find wiggling the unit up and down helps to release it from the dash.

Neil.

+1 on being careful during removal. I took one out without covering my hands and ended up looking like I had attempted to slit my wrists.

Post by **scot850** » 22 Oct 2017, 21:44

I'm not very familiar with the MCC version, but is it not cable operated? It could be just a cable has come loose, I had assumed your car was ECC as most here in Canada are.

Neil.

readallthebooks · Post by **readallthebooks** » 22 Oct 2017, 22:10

hmm maybe? i don't really know much about it myself either. i searched around but couldn't find anything about cables coming loose... maybe a piece of plastic broke somewhere? it seems weird that it defaulted to full heat.. i guess i'd expect it to remain at whatever setting it was on before it presumably broke.

Post by **abscate** » 23 Oct 2017, 00:54

All our cars use full flow heater cores and AC evaporators so the temperature is adjusted by blending the hot and cold air. I'm sure you just have a simple mechanical failure of the blend door which is just admitting hot air to the driver side. Slide under dash and follow the cables to the system and look for things fallen off.

If it disappears into the jungle , you might have to take the dash off yo deal with it. Ugh, 10 hours of work.
I'll look and see if I can find MCC info in Alldata for the superior 1999 model, practically perfect in every way...

It looks doable from inside car...

readallthebooks · Post by **readallthebooks** » 23 Oct 2017, 15:10

started to dig into this. pulled the kick panel and carpet and found the cable had come disconnected from this lever here. i put it back on but there's something further up the line causing it to bind, so i took it back off and just wedged the blender to be fully closed to hot air. i pulled the radio because it takes like ten seconds, but the cable mysteriously disappears somewhere and doesnt go directly behind the radio. gonna leave it like this for a minute until i have the time to pull out the climate control head unit

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