Went out to make a short drive in the blazer and before I left I had to brush off the snow accumulation from off the wind shield. I made sure the entire path of the wiper blades was clear of ice and the blades weren't stuck (I stick them in the air when I park the car, so they were not frozen to the windshield). The car had heated up a bit, but not much. I tried to use the wipers to clear the barely one centimeter of snow build-up that had accumulated while I was clearing other parts of the car and they didn't budge at all.

I replaced the wiper motor last year with a used one from a junker, so I immediately thought that it died, however after restarting the car I tried to use the mist function and the wipers still didn't work (no surprise there). So I unbuckled and just as I was about to open the door I tried one more time to use the wipers normally and they worked! or at least until I turned them off again. Tried repeating the process and they refused to move.

Next I moved the wipers a bit manually with them on and their movement seemed jerky, but they would move a bit if I pulled/pushed them through their cycle gently. I didn't line them up with their "rest" position exactly and after starting the car one more time the motor immediately, with no problem pulled them back to rest, however I still could not use the switch to turn them on again.

Not sure what is going on here, my guess at first is the motor, but the idea that it was able to so easily pull the wiper blades back into the rest position tells me it might be something else.

My second guess is the multi-function switch. It has shown some signs of failure in the past, like when I turn off the high-beams it won't turn my low beams back on and instead leave me in the dark.

 

The wiper motors are known to have issues at the soldered joints under the black plastic cover. I believe there is a thread around here somewhere that details how to re-flow the solder joints. It seems possible that could be your issue since it's intermittent.

Also, something to check- the wipers on my jimmy didn't work when i got it. It was as simple as unplugging the motor and plugging it back in securely to get them working. It had vibrated loose a little- i cleaned the connections while I was there too.

 

I went out to try removing and unplugging the motor, and I also cleaned the connections with no luck. When I activate the mist mode (wipe until you release ) I can hear rapid clicking coming from the engine bay somewhere. It's cold out and snowing pretty hard so I didn't stay out long to test it as I was starting to loose feeling in my fingers.

I guess the fact that I hear it clicking means it isn't the mutli function switch.

 

Hmm, if you can hear it clicking like that, I would take a look at where the output shaft comes out of the motor and meets the linkage and see if it's slipping there. Could have stripped the splines on the shaft.

Have some one hit the switch so you can watch. Youu may have to remove the plastic cowl cover to see it, I forget to be honest

 

Just when things couldn't get any weirder they start working fine. I drove to the scrapper regardless and got a new motor (in 2 feet of snow might I add) and as I'm driving out the wipers quit, but I also notice the fan is no longer blowing. Half way home I fiddled with the fan and it started again, and then I tired to use the wipers and the wipers moved an inch and died taking the fan with them.

I read online and a lot of people are saying it could be a relay or a major fuse somewhere. Any ideas if this could be it and if so what fuse/relay?

Seems similar to what happened in this thread, but I have no idea what he did or if it worked.

https://blazerforum.com/forum/2nd-ge...day-too-64174/

I'd like to check the blower relay next, but the diagram on this page says nothing about it's location.

 

SOLVED

TLDR; Tightened the bolt for G117.

When I replaced the hood after hitting a deer a few weeks ago I didn't reattach the hood light (I have plans to do this later as it is rusty and I wanted to clean it up). I kinda just put the ground back on loosely thinking it was a ground for just the light. Few weeks later and the bolt came loose allowing the wire to move, breaking contact with the firewall and shutting down the wiper and blower. Simple fix was just to tighten the bolt fully.

On the bright side I got a spare wiper motor now.