I have a 2001 volvo s40 and since I bought this car (5 years ago) i've had problems with the heat/ ac blowers. Whenever i start the car the blowers run for 5 seconds and either (a)continue to work fine for that trip or (b) turn off completely and i'm not able to use any heat/a.c function. It's a 50% chance that the blowers will work for anygiven trip or not work. This is not a setting issue with my heating controls. If the blowers are not working i have to turn the car off for about 30 minutes and pray that they'l come back on (50% chance). Any advice before i start sinking money??
Thanks!!!

 

I would try to check/replace the fan resistor. Does the fan work if you turn the speed full blast?

 

Fixed mine. Fan would only work on full.

 

Thanks rspi and hudini!! The fan works more consistently on full blast but when it doesnt want to turn on, it doesnt matter what speed i am running the blowers on. Still think its the resistor? If so, how difficult is it to replace? I'm also reading on other forums that it may just be the thermal fuse, would this make sense for my case or would my blowers not work at all if it was the fuse? thanks

 

I'd do the resistor.

 

Are you good with soldering and electrical components? Rumor has it you can replace the resistor (round silver piece in picture) with a radio shack replacement for very cheap.



2N3055 NPN Transistor
http://www.radioshack.com/product/in...ductId=2062614

 

Hello, I tried changing the fan/motor resistor but that didn't do anything... would my next step be changing the coolant modular?

 

Get up under the pax side dash and check the fan connections. Before changing my resistor I checked the fan wiring to make sure all connections were tight. I even hooked it to the battery direct to make sure it worked with straight 12v power.

I did find a strange extra connection between the original wiring harness and the fan. IIRC it was a recall item for the dealer to add into the existing wiring to fix some problem with the defrost. Does yours have this extra wiring harness?

 

2N3055 NPN Transistor : NPN Transistors | RadioShack.com

2N3055 NPN Transistor

 

I have to thank you for all the advice, it saved me money, the blower packed in on one of the hottest days of the year, I left it weeks before I really needed to fix it as 28degree heat isn't fun in a car with a faulty blower. After reading posts on this forum the problem with the blower in my v40 was intermittent. It wouldn't work at all for weeks then on starting the car the blower would kick in full power as it was set to max. The moment I'd change the power setting it would stop entirely and not work for weeks again. In the end I chose to test replacing the 2N3055 NPN Transistor (£2.89 from Maplin) researched the blower (found this diagram: 2000 VOLVO V40 Parts - VolvoWholesaleParts.com sells Genuine Volvo Parts ) and with a little help from Gatos' extremely useful guide to replacing the blower transistor here: GUIDE: How to replace the heater resistor - Volvo Owners Club Forum I managed to get the blower and aircon working in under 1 hour. A little soldering was required on the 2N3055 NPN Transistor pins but the minimal cost of this test outweighed paying for parts on ebay etc. at over £45. - Saved approx £42 + labour charges! Cheers

 

I'm about to buy the transistor pin, but where do i solder it? Could include a quick picture of the soldering? I've already replaced the resisitor.

Appreciate the help.
Jim

 

I've no pics unfortunately, I soldered the two pins on the transistor that go through the heatsink to the two longer and thicker wires from the heatsink/resistor unit. It appeared someone had already changed the transistor in the past and crimped the connections and used a paste to help prevent it falling apart, hence soldering was necessary for a reliable connection. Test before soldering by loosely connecting the pins to the wires, switch on the ignition, test the blower controls, if they work chose if to solder or not, refit the unit, job done.

 

IIRC the resistor only fits one way due to the little bolt holes being off center. I too soldered the wires to the pins. It was a little shaky my cheap solder gun as the pins and wires are quite thick. Plus you need to keep the wires/pins from touching each other and the heat sink.

 

Hi guys,

I have a similar issue, so any advice is appreciated. Volvo S40, 2001, 1.8petrol, automatic trans.

Last summer the blower was turning on and off sometimes with the control **** in auto position, but it happened rarely, otherwise it worked fine. When it was turning on/off, the A/C did the same, the light was jumping between green and orange. It makes sense, because if you turn the blower **** to 0, the A/C turns off.

Some searching on the forum and I decided to replace the transistor. After that, the system worked fine, even on a long trip, but a couple of days later my wife said that the blower was not working. I started the car, it worked fine. After 2 days, she came home and said again, that the blower was not working. She did not stop the car so I could check it. No blower with the control **** at any position, but the A/C was on, light was green. That was wierd for me, because it should have turned off with no blower... Checked the A/C switch, it worked, I could turn it on and off. Ten minutes later I went back to the car, turned the key to pos II, blower worked fine. I started the engine, turned the A/C on, system was working as it should, at any selected blower speed.

Any idea what should I check? Fuses? Replace the transistor again?

If the problem comes back, I will not stop the car, until removing the cover under the glovebox and I will check the connector of the resistor and the blower...

Thx in advance.