1988 Volvo 760 GLE V6 Sedan with 68,000 original miles.I have problem with my cooling fan It doesn't turn on if I turn on my A/C. The compressor kicks but my fan doesn't.I checked the fuse the relays are fine. The mechanic says " its not gonna turn on if it doesn't make it to its warm/hot temperature.&Quot; is that true? Because my fan works fine on summers because I use my A/C a lot. But then now winter time.I use my A/C for defrosser it dont work. What could be the problem? I was thinking the auxiliary fan switch?