Simplest thing to do is check the fuses. Fuses effecting the side mirrors' movement is in the #11 position, and its heating is in the #26 position in the fuse box (or vice versa...trouble remembering...so check them both), under the hood closest to the driver's side windshield. Hope this is it and not the motor or some other electrical poltergiest. If #11 fuse if blown, your rear defrost won't work either. If #26 is blown, then the heated seats (if you have them) won't work either...another way to check your mirrors, by seeing if your heated seats work. BTW, always replace these fuses with the same one...they're color coded, and #11 is a 30 Amp while #26 is 25 Amp. Good luck and let us know if that's it.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.