AC Heater Blower Motor Wrong Motor?

[SinCity3500]

Hey all, blower motor went out while I was driving. Fuse and resistor are fine, compressor still kicks on, but no air movement.

Went down to an O'reillys, picked up a new one, got it halfway installed and realized there's one a plug to connect the positive wire to, and no negative wire/terminal connection. Old AC Delco blower motor had both leads to connect to..so took it back down to store, clerk was surprised. Hour later all there other ones are the same, made by Murray. We look online and they all look the same, just 1 plug for positive, no negative.

Is there something I'm missing? Truck is a '98 k3500 7.4L.

 

[HotWheelsBurban]

Hey all, blower motor went out while I was driving. Fuse and resistor are fine, compressor still kicks on, but no air movement.

Went down to an O'reillys, picked up a new one, got it halfway installed and realized there's one a plug to connect the positive wire to, and no negative wire/terminal connection. Old AC Delco blower motor had both leads to connect to..so took it back down to store, clerk was surprised. Hour later all there other ones are the same, made by Murray. We look online and they all look the same, just 1 plug for positive, no negative.

Is there something I'm missing? Truck is a '98 k3500 7.4L.

No, what you have to do is move the other (ground) terminal over from the old motor. You also need to move the brass colored metal T washer tubes over from the old motor. I used a Murray unit on my '97 C3500 CCLB last week, and I had to move those items over. I was replacing the original motor, was built 2 days before the truck was built.
My post in the"what did you do to your 400 today?"thread has pictures and more details.

 

[HotWheelsBurban]

It's post #32,198 on page #3220 in that thread, posted September 18.

There's a small hole near one of the mounting bolt holes for the self tapping sheet metal screw that holds the tab on, to go in. IIRC it's a 6mm or 7mm hex head, I used a nutdriver that size and got the screw started and run in tight with the motor on my lap. I also scraped paint off under where the ground terminal mounts, so it'll make good contact. These trucks are VERY picky about having good grounds!
I think GM and the aftermarket are using the same motor for several different applications, and some use the separate ground terminal and some don't.

 

[HotWheelsBurban]

Here's a picture to clarify....