Blower motor won’t run on high

[prestonwood9]

Hello, my blower motor seems to run correctly on all settings except high. When switched to high it shuts off completely. I have already replaced the selector switch in the dash, the blower motor resister under the hood. Not sure what could be causing the problem still..? The only other item that I think could be malfunctioning would be the small device in the picture below? Does anyone know what this thing is? It seems to be grounded to the frame. Not sure why the wire just doesn’t run directly to the blower motor. Any advice is greatly appreciated.

1980 C10 factory A/C Big 10 Edition

-Preston

 

[prestonwood9]

Or could it be the high speed relay? Have not tried to replace this yet.

 

[WP29P4A]

That should be a noise suppressor, if it was bad, none of the speeds would work. It is most likley the high speed relay.

 

[prestonwood9]

Thank you for the info. What does a noise suppressor do? Is it something that is absolutely necessary? Just trying to make the truck as simple as possible. Thank you again.

 

[fast 99]

Noise suppressor is for radio interference. If that was the problem wouldn't work on any speed. High speed uses a separate circuit. Might be an inline fuse near the center of the firewall.