replacing wiper motors

I was wondering how hard it is to replace wiper motors? I have a '98 silverado. I was driving home yesterday and when I went to turn the wipers on I heard a humming noise and the wipers never turned on.
I got out and pulled up on the blade and that got the wipers to start moving. It's happened more than once.

Have 93 You Prob Won't Have To Replace Motor Just The Front Plate It Has Two Tabs That Make Contact With Motor One Of These Wore Off. Sorry I Don't Remember The Name The Parts Store Called It. Just Take The Screws Out Of Front Of Wiper Motor And Check Tabs If The Solder Is Worn Off Of One Thats The Problem Parts Store Had Both Just The Plate And Whole Assembly.

I had the same problem with my 93. The motor was actually not at fault, it was just a loose connection. I made a cheap fix, taped two pieces of a ruler together and wedged it under the connection to apply pressure and force the connection to connect. Your problem might be similar and you may be able to make a cheap fix. if the motor does need to be replaced, it is fairly simple to remove and replace. Just make sure that when you disconect the motor from the wiper assembly arms, the tab that connects to the motor doesn't fall behind the firewall, cause it will be pretty hard to get out. and also make sure to align the motor and wipers properly because if youd ont you'll have to take it all off and do it all over.

Rob I did that on mine first got about six months out of it but when the solder contact wears off you will have to replace the module it might last longer if you take module out and move some of the dilectic grease into the groove from contacts I think this is the reason for wear when they applied the grease on assembly they put it in the wrong places.