LBZ HVAC Issues

matthew86

Member
Mar 16, 2018
55
2
8
Eastern WA
My Google fu is not strong, but I have looked all over for help with this issue without any luck. My truck is an 06 CCSB with the dual zone automatic climate controls and before departing on a cross country trip, I noticed my heater fan was not operating. I checked the plug going to the blower motor, and the voltages were correct for what I found on the internet somewhere and varied with turning up the fan speed. As best I can tell, this truck doesn’t have a blower motor resister and just varies voltage to the fan. I replaced the blower motor/fan assembly and it seemed to work. Fast forward about two weeks and I start my truck up and the fan no longer works again. I have turned the temperature up and down on driver and passenger controls, tried every setting combination for feet, defrost, auto/manual, etc and no luck. I’m to the point where I am not sure what else to do but start throwing parts at it and replace the actual climate control unit on the dash hoping to fix the issue. It is still getting between 7v on low and 12v high if I remember correctly. Fuses and such are good. Anyone have any suggestions?


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juddski88

Freedom Diesel
Jul 1, 2008
4,657
120
63
Chesterfield, Mass.
There is a blower motor driver/resistor. Lots of times it is a loose connection at the plug that causes the issues, but I have replaced several bad drivers. Another symptom can be a wonky blower motor speed when control is set to auto. The control unit is least likely to be your issue.
 

matthew86

Member
Mar 16, 2018
55
2
8
Eastern WA
There is a blower motor driver/resistor. Lots of times it is a loose connection at the plug that causes the issues, but I have replaced several bad drivers. Another symptom can be a wonky blower motor speed when control is set to auto. The control unit is least likely to be your issue.

Ok. Thanks I will try to see if I can find it. I’m having issues getting my alldata to load due to data and lack of internet since I’m traveling. I must have misunderstood something I read.


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dcpjfs432

Member
Apr 14, 2018
41
1
8
My Google fu is not strong, but I have looked all over for help with this issue without any luck. My truck is an 06 CCSB with the dual zone automatic climate controls and before departing on a cross country trip, I noticed my heater fan was not operating. I checked the plug going to the blower motor, and the voltages were correct for what I found on the internet somewhere and varied with turning up the fan speed. As best I can tell, this truck doesn’t have a blower motor resister and just varies voltage to the fan. I replaced the blower motor/fan assembly and it seemed to work. Fast forward about two weeks and I start my truck up and the fan no longer works again. I have turned the temperature up and down on driver and passenger controls, tried every setting combination for feet, defrost, auto/manual, etc and no luck. I’m to the point where I am not sure what else to do but start throwing parts at it and replace the actual climate control unit on the dash hoping to fix the issue. It is still getting between 7v on low and 12v high if I remember correctly. Fuses and such are good. Anyone have any suggestions?


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I’ve changed probably 5 Blower motor resistor between my 04 LB7 and 06 LBZ 99% of the time that’s the problem you can get them at autozone and they have lifetime warranty if it goes bad just get a free replacement.


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matthew86

Member
Mar 16, 2018
55
2
8
Eastern WA
I’ve changed probably 5 Blower motor resistor between my 04 LB7 and 06 LBZ 99% of the time that’s the problem you can get them at autozone and they have lifetime warranty if it goes bad just get a free replacement.


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I’ve had troubles with those before as well on other trucks of mine. I would lose one or more of the number settings on manual controls for fan speed. This truck has the digital temp display with the dual knobs. I have noticed one out of every 10 or so times I start the truck, the fan will work normally on all levels I set it to, but of course it won’t work when there’s ice and such and I need defrost. I’m working on some projects for my mom at the moment as I’m visiting her across the country, but in the next day or two I’ll get to look at the truck again and let you guys know what I come up with. I appreciate all the input.


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