I have a '97 four door blazer. The drivers seat moves up and down just fine whether someone is in it or not. However, fore aft works fine when empty but requires human assist to go fore or aft when someone is in it. I assume the motor is 'tired' and needs to be replaced. I have spent over an hour searching ebay, amazon and standard internet searches including several of the online parts houses. I can not find replacement motors for my seat. Are they replaceable? Has anybody found them online? Who sells them? Do I really have to go to the MFG to buy them? (I am, by nature, extremely cheap so I avoid the dealer when I can.) Can these be rejuvenated?