Climate Control Woes

[AnthonyR]

Hello,

Don't post here too often but after a 2.5 hour slow drive with no blower fan in sub-zero temps I really need to jump on this.

The Problem:

Blower fan doesn't work, and the 1 in 20 time it does, there is a little bit of a groaning noise and the fan pulses all the way up and down repeatatly.

What I've done to try and fix it:

Took the fan out, bench test fine, spun up no problems and no noises or vibrations, everything perfect. There was a bit of corosion in that intermediate plug thing on the blower fan, but I cleaned it up. worked for a week or so and now has died again. Took everything out and everything tested fine, no corrosion on that plug and everything seemed fine. I have also tried a new resistor module to no avail.

Now looking at the codes and the service manual the code I am getting is B1: 4-1-8 which is "No Control Signal to ECC Power stage"

So I took out the meter, and the unit is getting power/ground just fine.

on the resistor module there are 2 plugs, one has two pins (large guage) one is ground, the other runs to teh blower motor.

on the other plug there are 4 pins, one is power, two are voltage supplies, one is the control signal, the other the diagnostic return signal. The service manual says that the control wire should show "12 Volts (square wave) constant frequency with varying duty cycle." Now my meter on this wire shows a semi sporatic AC signal (probably the square 12v signal) but is only showing ~4VAC and the 4th wire on the module "the diagnostic signal" shows ~1VDC which according to the service manual means "no control signal"

Now all this leads me to believe that maybe my climate control module in the dash is suspect, but thought it would be pretty rare for one of those to fail.

Anyways, any help would be greatly appreciated,

Thanks

Anthony

[Kashif]

I think it might be the climate control module. We had a similar problem on a used 850 that my Mom bought for my brother. The Car's whole climate control was just acting crazy. This link explains the problem http://volvospeed.com/vs_forum/index.php?a...&pid=859248

What was really weird was that Fan control would never work when you would switch it on. It had mind of it's own, eventually I pinned it down to a faulty climate control module. We went to a junk yard and got old unit off a 96 850, and now it runs fine.

[AlvinL]

Hello,

Don't post here too often but after a 2.5 hour slow drive with no blower fan in sub-zero temps I really need to jump on this.

The Problem:

Blower fan doesn't work, and the 1 in 20 time it does, there is a little bit of a groaning noise and the fan pulses all the way up and down repeatatly.

What I've done to try and fix it:

Took the fan out, bench test fine, spun up no problems and no noises or vibrations, everything perfect. There was a bit of corosion in that intermediate plug thing on the blower fan, but I cleaned it up. worked for a week or so and now has died again. Took everything out and everything tested fine, no corrosion on that plug and everything seemed fine. I have also tried a new resistor module to no avail.

Now looking at the codes and the service manual the code I am getting is B1: 4-1-8 which is "No Control Signal to ECC Power stage"

So I took out the meter, and the unit is getting power/ground just fine.

on the resistor module there are 2 plugs, one has two pins (large guage) one is ground, the other runs to teh blower motor.

on the other plug there are 4 pins, one is power, two are voltage supplies, one is the control signal, the other the diagnostic return signal. The service manual says that the control wire should show "12 Volts (square wave) constant frequency with varying duty cycle." Now my meter on this wire shows a semi sporatic AC signal (probably the square 12v signal) but is only showing ~4VAC and the 4th wire on the module "the diagnostic signal" shows ~1VDC which according to the service manual means "no control signal"

Now all this leads me to believe that maybe my climate control module in the dash is suspect, but thought it would be pretty rare for one of those to fail.

Anyways, any help would be greatly appreciated,

Thanks

Anthony

Anthony,

Check for a bad connection somewhere. Easy check by taking down the kick panel, pushing/moving the wires with the system on and see if the fans comes on.

In my case, I had taken my motor apart one time for service and reinstalled that snap on connector but the 1/4" quick connect wasn't connected properly inside. It resulted in the symptoms you described along with setting a code.

Good luck!

[AnthonyR]

Anthony,

Check for a bad connection somewhere. Easy check by taking down the kick panel, pushing/moving the wires with the system on and see if the fans comes on.

In my case, I had taken my motor apart one time for service and reinstalled that snap on connector but the 1/4" quick connect wasn't connected properly inside. It resulted in the symptoms you described along with setting a code.

Good luck!

Yeah, right after posting this originally, I did that and it turns out that the insulator (that snap on connector) is bad, and the new one should be at the dealer today (yay for $1 vs $200)