Climate control blower

[greg850r]

Hi all,

I have a 96 850T sedan I just put a head on and everything went well but the blower won't work. I already changed the ECC, the resister with the fins on it and blew out the 2 temp sensors in the cabin. I also tried jumping the pressure switch under the hood. There is 12v power at the blower motor. The ECC lights up and I can hear the damper doors working. It's giving me the twenty second flashing 2 lights when I turn the key on to show there's a fault. Results are the same with swapped in parts as with what came on it. The car is new to me. Bought it and drove it home with a burnt exhaust valve and cannot remember if I tried the climate control on the way home. I may not have though, because I did find the 2 wires that control the compressor were not plugged in and from the connectors' appearance I think they have been hanging unplugged for a long time. I scraped the metal clean and plugged them back in. All changes were to no avail and the blower and compressor will not engage. Sliding the fan switch between auto and manual I get the same result. Looking for what else to check. Does anyone know anything I could look at next?

[ZionXIX]

Is it possible to power the blower directly to ensure it works?

[greg850r]

I did reach in through the cowl and it spins by hand like a new one so not locked up and bearings are good. I guess figuring out where to put 12 volts will be my next step. I'm willing to bet it does. 130xxx mi one owner car with a lot of new Volvo parts on it and the compressor won't kick on either so I think it's probably not the blower motor.

[ZionXIX]

I did reach in through the cowl and it spins by hand like a new one so not locked up and bearings are good. I guess figuring out where to put 12 volts will be my next step. I'm willing to bet it does. 130xxx mi one owner car with a lot of new Volvo parts on it and the compressor won't kick on either so I think it's probably not the blower motor.

Not that I've tried but I would think if you connect 12v backwards ththe motor will just spin in the opposite direction. If you remove the glovebox and knee bolster there is a plug pointed towards the center of the motor at about 7 or 8 o clock position.

[greg850r]

I just put a 'new' blower in from a donor car. I tested both on the bench and got nothing from either, so with nothing to lose I put the other one in and it runs. Compressor won't go though. I put 12 volts to the wire and the clutch engages. Tried jumper on the pressure switch by the firewall but still nothing. Added 2 cans of freon without it running and they both went in.

[abscate]

You check integrity of an AC with vacuum before charging. An unknown history on a P80 usually means a leak in the System.

The wiring from connector to motor went on my T5 a couple years ago, it was an intermittent failure of blower

[erikv11]

I commonly test blower motors by putting 12v to them on the bench, a good one will spin right up.

As far as the AC hopefully it's not the evap core (but likely it is).

[greg850r]

My vacuum pump isn't here at the moment so I skipped that step. I did push the valve and there was some pressure in the system so it wasn't open at least. I was willing to risk a can of freon or two. If I can't get it to turn on the next thing I'll do is make a connector and plug the compressor right to power so I can run it and see what happens.

[abscate]

Dont vent any gas to the atmosphere - not only is it illegal, if your neighbors don't like you they can collect a 10,000 USD rat out fee on you. (Your test is a fair one and releases negligible amounts of R134A)

Testing with vacuum is much faster and better practice. Take a borescope and check your evap out too - these rot out on the P80s. Thats a cheap part and just stupid labor to get to it, about 10 hours during which you can replace the heater core and dash squeaks, too.

Ive found my local AC place will evacuate for free if they can keep the R134A, which is fine by me.

[greg850r]

Ive found my local AC place will evacuate for free if they can keep the R134A, which is fine by me.