HVAC blower only turns on at setting 5; no blower action at all on settings 1-4. At #5, very limited air flow from any vents; face, foot, defrost. A stretch to say it is blowing at even a normal #1 fan speed.
Resistor and blower motor replaced within last year. Took them out for visual inspection yesterday and both appear ok, no visible issues with either. Original was melted and easy to see the trouble. Has worked well since the repair, until now...
Looking for advice on next trouble shooting steps - I assume the resistor and blower motor are still "good". Switches on dash? Vacuum problem with doors in ducting?
Thanks to all in advance!
HouseCallAuto 2/10/2014You have a totally clogged cabin filter, that is preventing the strong airflow. The 1-4 blower speeds is a bad blower resistor or a burned connector that goes to the blower resistor.
HouseCallAuto 2/11/2014if it does not come out from the vents when the mode is set to vent, do you feel it coming out another place? Floor or defrost? If it is that you hear the blower running at high speed yet little or no airflow from anyplace then you may have a stuck mode door actuator. try removing the actuator and manually moving the mode door. You will need to get some repair info from a manual or online so you know how to access the mode door actuator. Its not bad to do.
HouseCallAuto 2/13/2014No they are not the same. The Mode door >. DORMAN Part # 604113
The Blend door >. DORMAN Part # 604101
HouseCallAuto 2/17/2014The fault code P0139 is not a code that is applicable to an '01 Chevy Silverado 5.3 but the code is a valid code on some other make. I suspect you read it wrong. I would understand mode only or blend only going bad. Never saw both. The resistor yes all the time goes bad but when the resistor fails more than once then it is time to replace the blower motor (drawing too much current) or else a burned connector at the resistor or blower motor.
HouseCallAuto 2/26/2014Replace the driver side front O2 sensor. It would be wise to replace BOTH front O2 sensors. These are the two sensors located before the cats. There is one on each side. It is a fault with the heater circuit of the Bank 1 sensor 1 heater circuit and the fix most often is replacing the O2 sensor. Sometimes it is a wiring issue but not that often.
HouseCallAuto 3/8/2014Check the fuse labeled FRT HVAC which is a 30 amp fuse that is only for the # 5 setting. Check the orange wire at the blower resistor with connector unplugged for battery voltage with key on and blower switch on # 5 setting. If no voltage there on 5 then the blower switch is junk. If the fuse is good and there is voltage at the orange wire then the relay that is only for high blower is junk. The speeds 1 through 4 do not go through this relay the same way. Only highest speed uses the function of this relay to flow separate power from the FRT HVAC fuse just to operate speed # 5.
HouseCallAuto 12/18/2014Check the blower motor itself by running temporary 12 volt jumper lead and ground lead. Remove connector from motor. If it is easier you can just remove the motor to check it not mounted in the vehicle because sometimes getting to the terminals of the motor with it in place is a pain. Also, make sure that the connector at the blower motor or the resistor is not burnt / melted as that would also kill all speeds. Also, check fuses labeled HTR - A/C (25amp) and also FRT HVAC 30 amp.