1996 Volvo 850 engine cooling fan

  • 1996 VOLVO 850
Engine Cooling problem
1996 Volvo 850 Front Wheel Drive Automatic 220000 miles


We have been having problems with our 1996 Volvo 850, 2.4 liter engine which I just basically inherited. The car kept stalling intermittently and running very erratic. I have some mechanical aptitude(I just rebuilt my 1990 Ford F250 with a 460 engine). I was able to troubleshoot it and ended up replacing the thermostat and the coolant temperature sensor. I can keep the car running, but the cooling fan will not come on as it should. What I have been doing is running a jumper wire from the battery directly to the connector that goes to the fan. This is a two speed fan and I run the jumper to the red wire-high speed and keep the fan running all the time while the vehicle is operating. Of course, when I shut the vehicle down, I have to get under hood and disconnect it, so I don't drain the battery. I was thinking of hard wiring it into one of the non fused circuits that is available in the fuse panel, so the fan would come on and off with the ignition on high speed. Is there a problem with doing this? I have checked the cooling fan relay and it is good. I suspect there might be a problem with the engine computer (which I would rather not replace unless I have to) or since I changed the coolant temperature sensor, do the codes just have be reset using the diagostic tool. These cars are expensinve to maintain and would prefer not spending a lot of money.

Looking back through the cars records, the coolant sensor and the themostat were changed twice in the past three years. So this make the third time.

Thanks a lot for your help.

Dean Quirion
Do you
have the same problem?
Monday, April 19th, 2010 AT 5:49 AM

1 Reply

Hi Dean,

Thank you for the donation.

The high speed mode of the fan uses a rather high current and it should never be used without any fuses.

To understand the system better and provide advisews on what to do, I would like to know if your vehicle is the Montronic 4.3 or 4.4 version.

Do you hav a schematic of the cooling fan system?
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Tuesday, April 20th, 2010 AT 10:46 AM

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