Car caught in a flood. Now cooling fan will not stop running. 2004 S60

GEL · Post by **GEL** » 20 Jul 2025, 10:29

I was caught in a flash flood. The water entered the passenger compartment and was up over the car seats. The trunk was also flooded and the battery was submerged. Fortunately, the water didn't get up as high as the ECU or fuse box in the engine compartment. I replaced the battery and after several attempts over the next couple days, which sent water blowing out of the exhaust, it started. I was able to fill the tank with fresh gas and I've put about 60 miles highway and local with only two problems: The first is there is an SRS warning even with two people in the front buckled in. I''m hoping this is just a sensor that still needs to dry out, but if anyone has any ideas on that I certainly welcome them.
The second problem is the cooling fan will not stop running. As soon as I connect the battery, even with the car cold overnight, the fan goes on and runs steadily even after I turn the car off again. I've been disconnecting the battery every time I turn the car off so it doesn't run the battery down,
Any ideas on what could be causing this? Someone suggested a relay could be stuck, but I haven't been able to find out where the cooling fan relay is.
Everything electrical seems to be working fine except those two issues. Any help I can get will be appreciated. Thanks..

Post by **DavidE7** » 20 Jul 2025, 20:00

The fan is somewhat difficult to diagnose if you don't have VIDA/DICE or a spare part out of a junkyard. The cooling fan is very easy to swap with only two bolts and a single electrical connector. It may be easier to disconnect the fan's electrical connector compared to disconnecting the battery. If the HVAC controller below the radio got submerged, it may be the problem.

Vova585 · Post by **Vova585** » 20 Jul 2025, 20:02

Bad situation. Water, fire, electric gremlins...if you can afford another car-run away from this car since it likely will be causing you issues every day(issues=money out of your pocket and lack of safety). Hopefully your insurance will be able to cover some cost, if not...if you have no alternative means of transportation...well, I believe this car uses fan control module(Grey metal box located at the back of fan shroud) it commands fan on/off and speed. Logically there should be 3 wires coming to that module(i dont have wiring diagram in front of me) 12v positive, ground (-), and command wire from body control module which actually tells fan module how fast to work and when. Clearly your issue is not power or ground(fan works all the time). Either your fan module failed and now constantly commands "on" or body control module wire damaged and shorting to power or ground(not sure of the strategy how BCM sends signal) vs issue is within BCM, or input to BCM is at fault(temperature sensor shows faulty signal and BCM thinks car is overheating). It is best to adress this issue with capable scanner and check what inputs(sensor info) your BCM is seeing, so you will know where the issue is(for example bcm commands fan 100%, so you know the issue is not fan control module or wiring, then you look at inputs to BCM and determine what is at fault.....I hope it will all is just due to water in some connector and it will be better in no time, but realistic side of me would suggest to run away from this car.

Post by **jonesg** » 20 Jul 2025, 23:11

GEL wrote: ↑20 Jul 2025, 10:29 I was caught in a flash flood. The water entered the passenger compartment and was up over the car seats. The trunk was also flooded and the battery was submerged. Fortunately, the water didn't get up as high as the ECU or fuse box in the engine compartment. I replaced the battery and after several attempts over the next couple days, which sent water blowing out of the exhaust, it started. I was able to fill the tank with fresh gas and I've put about 60 miles highway and local with only two problems: The first is there is an SRS warning even with two people in the front buckled in. I''m hoping this is just a sensor that still needs to dry out, but if anyone has any ideas on that I certainly welcome them.
The second problem is the cooling fan will not stop running. As soon as I connect the battery, even with the car cold overnight, the fan goes on and runs steadily even after I turn the car off again. I've been disconnecting the battery every time I turn the car off so it doesn't run the battery down,
Any ideas on what could be causing this? Someone suggested a relay could be stuck, but I haven't been able to find out where the cooling fan relay is.
Everything electrical seems to be working fine except those two issues. Any help I can get will be appreciated. Thanks..

the fan is designed to fail "on".
If the signal wire is shorted or severed the fan will not run.
Did water get in the relay mounted in the fan.?
If you have a pick and pull thats the cheapest route, otherwise FCP.
I ordered a fan, $550 at the time, turned out the problem was broken signal wire, I returned the new fan for refund.

Post by **Krons** » 21 Jul 2025, 20:55

The SRS control unit is under the center console, likely failed but best to check the codes of the SRS controller with a Volvo compatible reader. iCarSoft for Volvo on Amazon is ~$150 and easy to use.