climate control/heater fan

scenmed · Post by **scenmed** » 21 Jan 2011, 22:57

My 2004 XC90 fan is intermittent regardless of switch settings. The problem is that it's -13f in Minnesota this evening and not enough air flows to keep the windshield defrosted, not to mention driving with 4 layers of clothing is getting old. Here's the catch - if I place a 1500 watt electric heater under the glove compartment, facing the blower for an hour or so prior to driving the blower will come on full blast. Once the electric heater is removed (to drive away) the blower kicks off and will only come on occasionally. Is there a sensor telling the fan to quit or is the resistor reacting to the cold?

The only common denominator is when I apply this external heater the fan blower works. The colder the ambient temperature is the quicker the fan wants to quit. My extention cord is only 50'

so any solutions to this issue would be greatly appreciated.
Thanks in advance!
Cliff

Post by **jimmy57** » 21 Jan 2011, 23:04

ODD.
The transistor current controller for blower is under dash next to blower. I guess it is possible it could have cold temp related failure. I really think the fan motor needs to be checked to see if it binding up. Maybe the heat frees the bushings in motor.
The motor comes out the bottom with underdash panel removed and carpet and insulating mat folded down out of way.
I have a neighbor with a 2004 that was squeaking and slowing down and I pulled the vent hose off the blower, it is a black hose that plugs onto the black plastic blower cover, and sprayed WD-40 and blew the WD-40 into motor with a compressed air blower nozzle with a metal tube that has a 90 degree bend in it. Repeat the WD-40 followed by air a few times. I did this as they were heading somewhere the next day and he wanted it quiet if it was easy. He planned to trade the vehicle. That has been 3 months or more and he still is driving it and it still has a quiet blower. Lubing the blower through the vent hose is a trick dating back to mid 80's 240 models with chirping blowers. They'd chirp two weeks after replacing it. The lube n air trick fixed tons of them we never saw for that complaint again.
Did your blower ever get noisey before this sluggish blower thing cropped up?

scenmed · Post by **scenmed** » 22 Jan 2011, 00:16

Yes - the blower occasionally made a high pitched squeal mostly upon starting. The colder the temp, the louder the squeal. I'll be taking the blower out over the weekend (if temp gets above 0...NO garage)

Is a resistor likely to respond "on/off" to such cold temps?

Post by **jimmy57** » 22 Jan 2011, 08:12

Not that it matters but on that vehicle it is not a resistor but is a transistor amplifier circuit. I have not known of them to fail and be heat sensitive. The failure I have seen is the fan controller just dies and fan will not work or only works full speed.
The blower motor bushings binding and making for noise and low fan output is common. Yours seem to be slow but not squealing while it is running slow and that is not something I have seen. I have not tried heat on a misbehaving fan before so you've got me puzzled with that one.
I'd take the blower motor out and if it is bound up and is hard to turn by hand then I wouldn't replace the fan controller, just the blower motor. IF you pull the blower motor out and it is hard to turn and you warm it up and it gets easy to turn then you definitely have your answer that it is blower motor only.

scenmed · Post by **scenmed** » 22 Jan 2011, 09:50

Before I dive into the blower removal can you tell me if the glove box has to come out or is it just the lower panel. Also, since I was reading the procedure on an earlier model that calls for a T-20 and T-25 Torx and a deep 13mm socket can I assume this 04 is the same? It's 3 degrees outside so I want to make sure I have the proper tools "warmed up".

Again...THANKS in advance!

Post by **jimmy57** » 22 Jan 2011, 09:59

no glove box removal when I've done it. but the carpet and sound insulation will likely move way easier if heated for a bit.
I have torx 1/4 drive bits and long 1/4 extension and swivel (u joint?) to be able to get the back and side screws.

scenmed · Post by **scenmed** » 22 Jan 2011, 14:22

Are the pics in this link applicable to what I'll encounter or is the XC90 different?

https://www.matthewsvolvosite.com/forums ... t=0#p81434

Post by **jimmy57** » 22 Jan 2011, 15:09

The fan on XC90 is turned 90 degrees, it drops out the bottom of the case but is in the same area.

Post by **jimmy57** » 23 Jan 2011, 09:51

There is a post called "intermittent heater fan" in the S80 forum. Billofdurham posted a link to Volvo manual for blower removal. XC90 is the same except there is carpet and insul mat to pull down instead of a panel to the right to remove.

scenmed · Post by **scenmed** » 23 Jan 2011, 11:29

Jimmy57 Mega-Thanks for the info.

Here's the link: https://www.matthewsvolvosite.com/forums ... hp?id=7471