2001 S40 fan stays on after I turn off the car, I end up disconnecting the neg cable to turn it off, any suggestions?

 

any odd behavior in the temp gauge (suggesting the ECT sensor may need to be replaced)? There is a timer to turn off the fan after the key is off so you need to know if its just running on because it thinks the engine is still hot or because you have a stuck relay or a short in the fan motor etc. Did you try pulling fuse #15 (for the engine fan) to see if it shut off?

 

jbg, how long does the fan run?

 

Yes , the fans turn off

 

forever as long as the battery is connected

 

I'd like to jump in here as well since I'm having the same problem on a 2000 S40. In my case, you don't even need to start the car. On a cold car, simply turn the key on and off and the fan kicks on. I've already replaced the ECT, thermostat, cleaned and di-electric greased all related connections, and cleaned MAF; no help.

If I pull the relay (2/11) in fuse diagram, the fan stops, stick it in and it starts again. I have one on order, but until it arrives, does anyone know which connectors in the block I can possibly jumper to simulate a closed/open relay? I'd imagine in a fault free situation, pulling the relay would still prevent the fan from running? I'd just like to test further. Thanks a bunch!

 

So yesterday I took off the upper radiator hose and there was nothing in it, , wasnt wet or anything, so I put more fluid in and ran the car till the hose got hot and solid, the fans came on and off like normal , but when I turned off the car I still have the same problem of the them not turning off

 

That is same problem I have

 

I'm not familiar with your version S40, but almost always car makers use lots of the same relays, so chances are very good you can just swap a couple of 'em to see if the problem follows the relay or stays in the fan circuit (which will tell you whether the problem is the relay, or elsewhere). But a quick look online shows that they used an "oddball" relay for the radiator fan. It does appear the same one used for the air injector relay (again, not familiar with where that would be, but it might help).

 

Well there appear to be the exact same relays in the same block for other purposes. I swapped those around and still when I put a different relay in the radiator fan relay spot it still runs. Does not seem like relay at this point.

Really at a loss now to what the cause is? Not knowing electronics all that well, I’d love to know how to troubleshoot actual fan assembly before just buying a new one. Again, all I need to do is turn key to power on and off and fan kicks on. Even on cold car.

 

Is it the cooling fan or the AC condenser fan? Is your AC turned on all the time? Try turning it off if yes.

I once had that problem with the fan continuing to run. I first replaced the Coolant Temp Sensor with a new one from Autozone or Advance and the problem continued. I then replaced this brand new part with an OEM Volvo part and the problem went away. IOW, don't trust that just because you have a new part that it works correctly.

The actual answer is to check what value is being given to the computer from the temp sensor first. I'm a parts swapper though.

 

It’s the cooling fan. All parts installed so far are genuine Volvo so hoping they’re good. I believe the ECT is just 2 wires. Since I’m not an electrical guy could you kindly suggest what I can test with the ECT connector?

Other observations:
Turn key on without starting car - no fan
Turn key from on to off - fan goes on
Actually start car - fan does not go on until up to temperature
Shut car off - fan stays on

Thanks!

 

The ECT sensor is a thermistor - so to test you can disconnect the connector and measure the resistance. It should be about 3000 ohms at room temp (ie 70F or so) and in the 250 ohms range at operating temp (ie 180 to 190F)

 

Fixed!! MAF!

As for my issue with the radiator fan staying on, the car was in storage for a while and after putting it back on the road, besides the fan, it started running (and starting) more sluggishly. The only codes thrown were P0102 indicating bad MAF circuit. We ordered an OEM (Vdo) MAF for $120 from FCPEuro and after about 5 minutes of running and driving, the computer adjusted and started running much better. Bonus - the fan issue also gone.

Just wanted to post proof that a bad MAF can very well cause the fan to stay on when all other troubleshooting provides no solution. In our case, the MAF plate and wires had green oxidation that no MAF cleaner could cure. Possibly much worse inside circuit.

Thanks all for your input!!

-Steve

 

I have pulled the fuse and replaced it and it turns off and back on when I replace it, I have also replaced the relay with the same results, glad to see Steve fixed his problem , I am also going to change the MAF to see if that helps. as for checking the resistance in the thermostat sensor, I come up with 1.75 ohm with the engine cold, do I need to start the car to get the reading that was stated above?

 

usually when ECT sensors go, they either go very high ohms (ie open circuit) or very low (ie a short). Assuming you unplugged and measured correctly, no reason to retest at a high temp, the unit needs to be replaced.

 

UPDATE.....fan was bad and the fan module resistor, replaced both went for a ride and turned off the car and silence...