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?


Sent from my iPhone using Tapatalk

 

[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?


Sent from my iPhone using Tapatalk

 

[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


Sent from my iPhone using Tapatalk

 

[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


Sent from my iPhone using Tapatalk

 

[SunlitComet]

which doodad?

 

[DallasTahoe]

The blower motor resistor


Sent from my iPhone using Tapatalk

 

[SunlitComet]

do not. the resistor has no play on whether high speed works or not. when in hi speed the resistor is bypassed.

 

[DallasTahoe]

Ok so where is the blower motor relay located at so I can replace it?


Sent from my iPhone using Tapatalk

 

[SunlitComet]

you might have a bad hi-speed relay which is near the resistor or the speed selector is broken inside.

 

[DallasTahoe]

I'm thinking it's the relay because the switch panel is from my Tahoe and I know it worked, I'll try it swapping it tomorrow if I can get home early enough


Sent from my iPhone using Tapatalk

 

[DallasTahoe]

Ok a little update on this, so after swapping the relay, the resistor, and pulling my hair out because I was still having the same issue, I found the problem, and I'm thinking that many that have the same problem are overlooking the issue. I found mine yesterday while I was going through my Yuk checking it out all the systems (getting ready to put her on the road as my daily). I had turned on the heater to high and it wasn't working, so I opened the glovebox to get my flashlight and it kicked on, grabbed my light then closed the glovebox, and the heater turned off. So after doing this a few times I took out the glovebox and just kinda looked around and saw these two connectors. I started moving them and every time the heater would kick on and off. The factory location for these wires is in a bad spot and they touch the back of the glovebox and create a bad connection. The red wire here is the culprit, just move it back and zip tie it away from the glovebox and you should be ok, after checking and fixing the tightness of the connector of course! Good thing I didn't throw money at this issue, I woulda been pissed! Lol

Sent from my iPhone using Tapatalk

 

[SunlitComet]

where do the ends of the red wire go to on yours?

 

[DallasTahoe]

It goes the the relay on top of the heater box


Sent from my iPhone using Tapatalk

 

[SunlitComet]

do you know which end was effected? the end you're pointing to seems to be damaged.

 

[DallasTahoe]

do you know which end was effected? the end you're pointing to seems to be damaged.

Yea the one I'm pointing to, it got pushed against by the glovebox and it kinked the wire causing it to have a poor connection


Sent from my iPhone using Tapatalk