A/C issues 2007 V70 2.4L five speed.

SteveV70 · Post by **SteveV70** » 20 Jul 2022, 07:51

Could someone give me the low down on how the A/C is controlled?

Background:

When I bought the car not long ago the A/C didn’t work.
It was drawn down and held for 30 minutes and had no leak.
Refilled with the exact amount of Freon to spec.

I had voltage at the compressor connector so I reshimmed to spec and now the compressor works fine and it makes cold air.

But the way the air comes out is wrong.
Right side,…cold air.
Left side,…meh air.
I think the left side is only getting cool due to recirculation.

I’ve searched here, done all the simple stuff like “resetting from hot to cold” etc.
(Yes, both sides go to full hot when I set them there.)

What I did notice is that there was a little tiny bare wire sticking out of that little grill that I’m assuming is where the A/C system gets it’s cabin temp info. (No, there is no lint in it). But what is on the end of the bare copper colored wire is what looks like a tiny crystal or something. The picture is blurry but you can see it sticking out.

What is that? What I’d really like to know is what that sensor inside there behind that grill actually looks like.
I’m thinking someone tried to “pick it out” of there. And if I have to replace that sensor, and/or the left side temp control…what might be the part number of those?

SteveV70 · Post by **SteveV70** » 20 Jul 2022, 07:52

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SteveV70 · Post by **SteveV70** » 20 Jul 2022, 07:54

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Post by **chrism** » 20 Jul 2022, 10:14

I recall having the same symptom (cold on one side / warm on the other side) when my refrigerant charge was just SLIGHTLY low.

Normally I would suspect the LH blend doors aren't transitioning properly from hot to cold, however you report that when you set the dial to hot the output gets HOT. That would lead me to believe the doors are at least "trying" to work right. You might want to double check by comparing the movement of the LH vs RH blend door actuator arms when you switch them back and forth from hot to cold.

Post by **firstv70volvo** » 20 Jul 2022, 10:44

SteveV70 wrote: ↑20 Jul 2022, 07:51 Could someone give me the low down on how the A/C is controlled?

Background:

When I bought the car not long ago the A/C didn’t work.
It was drawn down and held for 30 minutes and had no leak.
Refilled with the exact amount of Freon to spec.

I had voltage at the compressor connector so I reshimmed to spec and now the compressor works fine and it makes cold air.

But the way the air comes out is wrong.
Right side,…cold air.
Left side,…meh air.
I think the left side is only getting cool due to recirculation.

I’ve searched here, done all the simple stuff like “resetting from hot to cold” etc.
(Yes, both sides go to full hot when I set them there.)

What I did notice is that there was a little tiny bare wire sticking out of that little grill that I’m assuming is where the A/C system gets it’s cabin temp info. (No, there is no lint in it). But what is on the end of the bare copper colored wire is what looks like a tiny crystal or something. The picture is blurry but you can see it sticking out.

What is that? What I’d really like to know is what that sensor inside there behind that grill actually looks like.
I’m thinking someone tried to “pick it out” of there. And if I have to replace that sensor, and/or the left side temp control…what might be the part number of those?

That's the thermistor for the CCM sticking out the opening. It is a variable resistance temperature sensor that provides the cabin temperature feedback to the CCM. With it pulled out like that I would imagine one of the two leads is broken and the sensor is not providing the temp feedback needed. Does the compressor cycle off after running for a short time? The thermistor is pulled out because it sits just behind the opening slots and probably got pulled out when someone was trying to clean out the opening slots.
At 25C the thermistor resistance is ~10K ohms and goes down from there as the temperature rises, if broken there would be open or infinite resistance so the CCM may react like the temperature is cold and not run the compressor or if it does run it would only cycle the compressor on for a short time.
I'm attaching some photos and notes when I replaced the thermistor in my car and I've included a part number of the thermistor I used. The only thing I'd add to the notes is to not even try to get the original thermistor leads out of the tiny holes in the circuit board, just cut out the old thermistor and leave the leads in the circuit and just solder the new thermistor to those leads. The holes are so small in the circuit board you can't remove all the solder and you can't get the new leads back into the holes so it's best just to solder the new thermistor to the existing leads. Don't unplug the CCM unless the battery has been disconnected first.

It's difficult but can you look through the opening and see if one of leads is broken?

CCM thermistor replacement.pdf: (2.54 MiB) Downloaded 70 times

SteveV70 · Post by **SteveV70** » 20 Jul 2022, 13:56

Well guys,…I’ll tell ya what,…that’s awesome advice.
I’m pretty sure that lead is broken because it’s a single wire tipped with that crystal.

When I get to it tomorrow I’ll report back.

Also, very nice to learn how the climate control is achieved in this car. This car was immaculately maintained by the original owner. There was a seven page Carfax for it. He had it shipped to Germany and back,…twice. Military man,..a captain I think. The second owner was not so good, and I’m glad they only drove it for about 60K miles or so.

They obviously were a family, and had a dog. How do I know? All the Fritos and junk under the seats. And also,…all the dog hair in the cabin air filter. That filter was dated April 2016 !! And that’s when the original owner sold the car.

And it was absolutely packed with dog hair. I thought at first that’s why the A/C wasn’t working right. But with a new filter, (and a good cleaning of the evaporator coils) it worked better, but not perfectly….mainly due to the thermistor as I have just recently learned. Gonna clean that little fan that moves air over the thermistor also when I get in there.

And thanks a million for the Mouser electronics thermistor tip. I priced the OEM one and it’s a hundred bucks. I love it when you can find and fix something for pennies that would ordinarily cost a bunch.

Thanks again guys.

Steve

SteveV70 · Post by **SteveV70** » 20 Jul 2022, 15:40

I just looked up in there with a flashlight and sure enough, the wire is broken.
So, I’ll be getting that apart tomorrow.

Love the V70
Love this site.

Post by **firstv70volvo** » 20 Jul 2022, 16:14

SteveV70 wrote: ↑20 Jul 2022, 13:56 Well guys,…I’ll tell ya what,…that’s awesome advice.
I’m pretty sure that lead is broken because it’s a single wire tipped with that crystal.

When I get to it tomorrow I’ll report back.

Also, very nice to learn how the climate control is achieved in this car. This car was immaculately maintained by the original owner. There was a seven page Carfax for it. He had it shipped to Germany and back,…twice. Military man,..a captain I think. The second owner was not so good, and I’m glad they only drove it for about 60K miles or so.

They obviously were a family, and had a dog. How do I know? All the Fritos and junk under the seats. And also,…all the dog hair in the cabin air filter. That filter was dated April 2016 !! And that’s when the original owner sold the car.

And it was absolutely packed with dog hair. I thought at first that’s why the A/C wasn’t working right. But with a new filter, (and a good cleaning of the evaporator coils) it worked better, but not perfectly….mainly due to the thermistor as I have just recently learned. Gonna clean that little fan that moves air over the thermistor also when I get in there.

And thanks a million for the Mouser electronics thermistor tip. I priced the OEM one and it’s a hundred bucks. I love it when you can find and fix something for pennies that would ordinarily cost a bunch.

Thanks again guys.

Steve

Dogs, dog hair = broken thermistor. I have two German Shepherds that shed vast amounts of hair and the horizontal slots in the CCM front opening suck dog hair in too easily, which stops the fan and why I added a screen over the opening. The previous owner of your car was likely trying to clean dog hair out of the CCM opening and caught the thermistor and broke the lead wire.

Post by **vtl** » 21 Jul 2022, 07:49

95% confident it's the driver's side blend door actuator. https://www.fcpeuro.com/products/volvo- ... or-8623354 Mine was giving me less cool air in summer and no hot air in winter. It still could be healed by a CCM calibration, but once the climate goes to full cold or full hot, it was starting doing that again. Replaced the actuator and all is good now. The job is PIA

SteveV70 · Post by **SteveV70** » 29 Jul 2022, 18:25

I wanted to follow up.

I finally got the time to get to the thermistor in the Volvo. Taking the dash apart to get to the CCM is a little different on the later series two cars, mine is an 07. But there was a video on that and it’s actually even easier. And since mine is a five speed manual there was more room with the shifter in fourth. I didn’t even have to pull the knob.

I was able to actually desolder the old thermistor and the one I bought went right into the old holes in the small mounting board no problem. The new one (from Mouser using the part number you gave me,..thanks!) had longer leads and a short stripped portion at the ends that was bare. I wasn’t sure if the length of the leads mattered…I know it matters on thermocouples so I didn’t want to shorten them and strip more wire bare. So I just used it as is and made the excess insulated wire leads into a soft loop and got the tip of the thermistor centered in it’s mounting tunnel.

Got it all back together and this thing throws serious ice cubes now,…both sides of the vents, all good. WOW.
The whole ordeal took about a hour and a half.

Looking back, I had a friend of a friend’s shop look at it initially and he wanted to replace the compressor and dryer…to the tune of $1600. I declined.

I did the reshimming trick on the compressor pulley and it snapped right back into service. This thermistor issue was the next domino to fall. Sooo,…what that tells me is that if I had gone with the $1600 “repair” it still wouldn’t have worked,…and likely would have been quoted some additional diag and work,…probably in the $1000 range to fix the thermoster. So,..it’s likely that if I had gone that route,..I would indeed have the awesome A/C I have now. But the likely cost would have been $2,600 or so….

Moral of the story is,….I fixed this entire thing for five bucks.

I LOVE this site.
I LOVE the V70

Probably will be the last car I ever own.

Steve