eng fan

unplug it under the hood, probably an airline controlling it, maybe a bad valve/solenoid

 

Not knowing if your truck has the solenoid in the engine area or you might have the solenoid pack back by the trans the test you can do with out looking at it is unplug the air line off the fan hub and apply air to it , in most cases its the fan that has failed , if you apply air to it and it does not release then replace it , if you have the solenoid under the steering shaft on the fire wall make sure you them together good luck ,****note do you know if its elec control or air controlled , what I mean does it have a air to it or just wires

 

If it's very cold out -5+ then wait to see if it works normal in warmer weather. Mine hates the cold and was just put on two months ago.

 

If you have been running the defroster(I hope you have in this weather) then it sounds like the high pressure switch on the A/C compressor took a dump. Try unplugging that, and someone with more Volvo knowledge than me can tell you if you need to jump the 2 terminals on the connector to turn it off. Completely disabling the fan even in this weather isn't a good idea in my opinion. Just my $0.02...