So it seems my truck is dieing. =P Not really. But I have a wiper motor that is dead int he back i believe. When i switch the wiper on all i here is a grinding noise. Im assuming a lose gear or something? Because if i hit it (the wiper arm) it will sometimes go all the way up and down. and then it wil start its fit agian. Or it will only make it half way.

Any ideas?

Price on rear wiper motor?

I hope its not that. It doesnt seem that. it just seems its not catching?

 

Try tightening up the nut that holds on the rear wiper.

 

Yeah I unfortunately have the same problem and probably just have to replace the motor. Of course now is the season I use it most since I kick up lots of sand/salt/snow and it just covers the rear window. I am looking into how to replace it. Mine makes a noise like it moves/engages for a second then stops, then when i turn it off the same noise happens as it resets to the standard resting position. its not the bold thats loose, and shouldnt be a fuse if it is getting power like it is. so probably just the motor.

 

Last night I took the rear hatch apart (screws, spring clips, inner panel screws (12), etc) and got to the wiper motor. Upon close investigation, the gear box attached to the motor can be opened up. The motor obviously works since it chatters so something else is not working, makes sense. I opened up the gear box, the motor shaft drives a worm drive gear (plastic) that meshes with a gear wheel (plastic) that has an eccentric cam (metal) on the gear wheel that attaches to a metal arm that meshes with another metal gear arm that is attached to a long shaft that passes through the hatch door and terminates with the finely splined end of the shaft (where the wiper attaches to). As the eccentric cam turns around the gear wheel, the metal arm moves back and forth thus creating the wiper effect. Lot of action in a small space, pretty cool actually). My basic philosophy is that if something can be assembled, it should be able to be DIS-ASSEMBLED (in theory anyway). So fiddling with the thing eventually led me to the conclusion that if I put the wiper nut on the end of the wiper shaft and gently tapped the nut I could drive the wiper shaft (and its metal gears and arms back out through the metal housing (Oh, forgot to say that the wiper shaft was "rusted" in its sleeve and would not oscillate back and forth). At the end of the shaft (on the outside of the vehicle) there is a metal "washer" that was an incredibly tight fit (this washer holds the shaft from falling into the gear box) so you have to keep tapping on the end of the shaft to eventually drive the shaft past this holding washer. Once I got past the washer the shaft would not pass through its guide sleeve in the metal housing (remember, "rusted" in place, seized). I tapped it out with a phillips screwdriver acting as a long punch. I then cleaned the interior sleeve by reaming it with a long circular steel brush (3/8" diameter brush that is designed to clean out push rod holes) and I polished the wiper shaft with fine sandpaper, then lubed and reassembled the whole smash making sure the wiper shaft now moves freely in its sleeve. Tonight I put it all back togther in the vehicle and we'll see if it works. Fingers crossed.

I wrote this top part back in 4/2007. The rear wiper has worked fine ever since.

 

So the motors good. Its just a fubar plastic lojac gear?

Let me know Junkmonkey. IM intrested to what you find.

 

I've had my Blazer for a year and a half and the rear wiper has never worked, and just realized the other day it has been switched on for the whole year and a half. I was pretty sure it was dead but I was bored this afternoon and took the sucker out and had a look. I thought it was impossible to take that gear box apart but thought I would check on here. Well thank you junkmonkey I took it appart, cleaned it up, soaked the parts in WD-40. When I went to lube it up with grease I realized I was out, but didn't have time to grab any so I just put it back together and installed it. Still skeptical as to whether it would work, and to my amazement it works like a charm now. I'll take it back appart and lube it up this weekend. Thanks again and I recomend anyone with a dead rear wiper to give this a try, only took a couple hours.

 

I had the same problem on my '96

I took apart the hatch and was able to get in the assembly, come to find out that main gear that is driven by the worm gear had teeth worn and it would not allow the wiper arm to get a full swing, i was however to able to give it a little push and it would cycle through only for it to get stuck again at the same spot...

Good idea is to try what the above had, if you still having problems, you can always get aused assembly from the junkyard for a good price :P ( lucky enough to get one for 10 bucks at a local junkyard and work the first go around :P )