Blower motor high clicks on and off

[dkraven]

Since getting the truck with a nonworking blower I’ve fired the parts cannon at it, multiple volleys. The system has a new blower motor, with all the ground connections cleaned because that was a problem. Also new relay, and new switch in the cab. Was thrilled when I fired it up and all 4 levels of the blower functioned. And then there was a click and high switched to medium 2. Moved the switch down and up and high came back on, and then clicked down to medium 2. And then clicked on a moment later. I would assume there’s something loose along the orange wire between the switch and the high speed relay but not really sure how to go find it.

 

[PrairieDrifter]

I had a similar thing. High would run fine for 1 minute or 45 minutes and anything in between then just randomly shut off completely. I could switch speeds and then right back to high and it would work again.

Brand new relay was bad. That may be your issue, but you could also have a short between high and 2nd speed.