Blower motor doesn't work on high

[yz2009]

Sorry I guess I should have asked my question differently. I understand the diagram and the red wire.

 

My question and where physically is the C4 junction box. And any other possible connections that could have a corroded pin. Is the C4 junction box right at the fuse box under the hood? The way I I read it is that C4 is the connector that plus into the resistor.

[Coby7]

Do you see this in the diagram that kinda looks like a grommet with P100 beside it. Well that's because it is a grommet in the fire wall. This means the red wire leaves the under hood area and enters the cabin area. I don't have one of these trucks and maybe someone else can chime in but by the looks of things that junction block is between the control unit and the resistor network. Did you splice the resistor network harness when you installed it or did it just plug into this junction spot?

 

[yz2009]

Coby7 is there any way you could pm me the photos? I'm still trying to fix my issues and I went to look at the diagrams you posted and apparently photobucket isn't allowing third party sharing so I can't see any of them now.

[jffmaz]

Worked on my B-in-laws 2000 Tahoe? a few weeks ago. Rear AC fans worked, Front fan was not working at all. Replaced the resistor and got all speeds except high to work. I found a fuse in the engine compartment fuse box was blown, 30A. Replaced it and all is good now, high speed works. If I remember the fuse was marked HVAC, but not sure. It was near the top right side of the fusebox when leaning over the fender. Seems that high speed is a more direct feed for the 12v, on a different circuit than the resistor.

I know old post, but maybe this will help somewhere.

[Dnt]

Bingo. Yes the resistor is bypassed on the older models and you simply have a dead fuse. Unfortunately most likely you have a bad blower motor or a dirty blower wheel causing the high speed fuse to blow in the first place. Do you have a mouse nest off down in there or what?

[jffmaz]

Bingo. Yes the resistor is bypassed on the older models and you simply have a dead fuse. Unfortunately most likely you have a bad blower motor or a dirty blower wheel causing the high speed fuse to blow in the first place. Do you have a mouse nest off down in there or what?

Yep, that was my B-in-laws problem. don't know how the resistor got broken, it was the earlier stock plate design known for breaking. Maybe the mouse was using it as a handball backstop while he was in there.