Heater hi not working

[DallasTahoe]

So my yuk doesn't have high heat, so I switched it with the control unit from my Tahoe that I know worked on high because I thought it was the switch, but after changing it, it still doesn't work on the highest fan speed setting. Is it the motor? Or something else?


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[SunlitComet]

there is the hot water valve under the hood and a vacuum solenoid mounted on the firewall which controls the vacuum to the valve. right side of engine.

http://www.gmpartseast.com/chevy/co...es-pipes-heater-tc080310108-l31m30k10706.html

 

[DallasTahoe]

there is the hot water valve under the hood and a vacuum solenoid mounted on the firewall which controls the vacuum to the valve. right side of engine.

http://www.gmpartseast.com/chevy/co...es-pipes-heater-tc080310108-l31m30k10706.html

So that will allow the fan to work at the highest speed setting?


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[SunlitComet]

crap. i just noted the you meant fan speed sorry...........

 

[SunlitComet]

there is a high speed relay and fuse that runs it at high. the relay is controlled from the hvac panel. first look under the hood in the power box and see if the blower fuse is blown let me know. also what year we talking?

 

[DallasTahoe]

Ok it's a 98 Yukon


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[SunlitComet]

use the following diagram with a multi-meter to test the circuits and find the fault.

 

[DallasTahoe]

No blower fuse blown, guess I'll check swap out the doodad on the heater box and go from there


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[SunlitComet]

which doodad?

 

[DallasTahoe]

The blower motor resistor


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