Need help diagnosing hi- speed fan blower motor problem

[buzz77]

Hey guys,

The hi on my blower motor simply doesnt work. I replaced the hi speed fan relay but to no avail. Would the resistor be the culprit or just a bad heater control unit in the dash? In fact does the blower motor even shut off? It seems that it remains on in a very low setting. Any ideas?

 

[foxtrot]

Check for 12 volts (when on high setting) on the thick red wire that plugs into the resistor. If the 12 volts is missing, check the connector in the harness that is routed over the passenger valve cover. I've seen a bad connection in said connector cause this issue on a few gbody's in the past..

 

[darbysan]

X2 on that connector. It's a know problem. High speed power comes through that connector.

 

[buzz77]

Thanks, I'll definately check that!

 

[RocketGremlin455]

X3 on the connecter. Just did mine a few mins ago. Connecter on mine was kinda dangling between the trans dipstick and the breather hose from the valve cover to the air cleaner. I no sooner pushed my multimeter probes into the grimey connecter and boom....high speed. So I cleaned it all up and plugged it back in. Perfect. I also replaced the switch on the controls with a Borg Warner BL-1 switch, since I already installed it before checking the connector. Ehh, it was $8.

 

[Longroof79]

X4 on the connector malady. It's a very common problem with these cars. Pull the connector apart and clean and burnish the contacts.