Radiator fan turns on after car off, drains battery

Trilarry · Post by **Trilarry** » 11 Jul 2007, 20:50

I was going to try and ask you to post on the s40 page but I noticed you already did. try this site if you are across the pond.

http://www.volvoforums.org.uk/forumdisplay.php?f=17

Tri

Post by **JRL** » 11 Jul 2007, 21:32

[quote="mkanjaria"]hi guys ive got a similar problem with my s40 the problem is that the fan stays on even if i put the knobs on 0 fan speed and the fan doesnt turn off when the car is on but does when the car turns off.
i went to the dealership and asked them to sort it and the gave me the following list of parts to get:
level sensor
particulate filter
control-----------bought this but problem still persists
transistor
totalling

icelandic · Post by **icelandic** » 12 Jul 2007, 17:43

A couple of weeks ago after finishing the replacement of the PCV and preventive replacement of the coolant temperature sensor, I ran into the same problem. I traced the problem to the connector of the coolant temperature sensor. After replacement, when I connected the new one, the fan immediately came on with a cold engine. I disconnected the sensor and found that due to age, the female contactors inside the connector were loose and actually moved back. What I did was to pull them out of the plastic housing and connect them to the plug, and then pushed the plastic housing around it. It fixed the problem. Perhaps your connector is also bad. Take alook at it. It is right above the alternator. Before disconnecting try pushing the two wires in. If it does not work, then disconnect and inspect connector condition.

Good Luck

Icelandic

aaronpaden · Post by **aaronpaden** » 16 Oct 2018, 20:15

1998 V70 T5 (manual 5 speed = yummy)

I also had this problem - the radiator fan would run - even if I just ran it for a moment or turned the key almost to ignition...
TWO NOTES:
1) For me the fan would eventually stop after a few minutes - but it happening enough was draining my battery down.
2) It exhibited cold start problems.
I replaced the ECT sensor and coolant thermostat (because I was in there) & I noticed that the connection to the ECT sensor was pretty ugly looking. This worked for awhile - but eventually the problem came back. I bought some electrical connection cleaning spray and some dielectric grease and cleaned it out well and greased the connection and I'm back to normal again.

ECT = Engine Coolant Temperature

The original sensor was for sure bad because it was reading the incorrect temp but I recommend really cleaning and greasing the ECT connection so that the problem doesn't come back.

Good luck!