My rear windshield wiper works great, but when I push the button for it to spray fluid on the windshield nothing comes out. I have held it for like 30 seconds one time and nothign came out. Yes, the fluid comes out on the front windows and yes there is obviously fluid in the container lol. What could cause this?

 

Probably either the switch (button) is bad, or the pump for the rear is bad. If you remove the reservoir (the single bolt you see right on top) there's two seperate pumps for front and rear. Both pumps should use the same type of plug so I'm guessing if you can pull it out enough to swap 'em you can try and see if the windshield squirts with the rear button (bad pump then). But first do you hear the pump run when you push the button? If so the rubber line has a break in it somewhere (like in the rubber boot between chassis and liftgate). Second how much fluid is in the bucket? Front pump is lower so your rear washer will quit working before the front does if the fluid is getting low.

 

Try switching hoses at the tank and using the front washer motor switch in the truck, see if fluid comes out in the rear...if it does then you have narrowed it down to the motor...you can find these at the recycling/junkyards for under $10.

I recently replaced the motor from my 1999 Grand AM with one from a 1990's Blazer... they are the same part type....