Pontiac Repair: 2001 Bonneville SLE heating/cooling, apparent force, havc

Question
QUESTION: I attempted to turn the heat and AC on in my car last night.  The digital display says everything is working properly but the fan will not kick on.  I noticed a very small amount of warm air coming from the vent with no apparent force.  I have heard this could possibly be a fuse issue but I'm not sure of which one.  What do you think?

ANSWER: Hi Tony:
well it's more than likely 2 things that could be wrong. I doubt it's the dash control module because you can control the fan speeds like you said. I assume this is an sse or an ssei because you mentioned digital display. it can be either the fan it's self bad or the blower control module. you have to check for power and ground at the blower motor it's self or the brower control module. check for power on the pruple wire and grouind on the black wire turn the fan up to high speed and you should have close to battery voltage across the purple and black wires. If not then you more than likely have a bad control module and to answer you origian lquestion yes it has it's own fues it's ptobably in the rear fues block under the seat and it going to be marked soemthing like fan or havc or blowr something like that is it going to be a stiff fues higher maperage maybe 20 or 30 amp. you can check that as well if it has power goinginto the module then I would have to say the module would be bad but you never know It' kind of a complex system the way the dash module controls the blower motor control module. before you checkthe wires to the motor just give the motr a tap with a screwdriver handle with the key on and the blowe ron high and see if possibly the motor has a flat spot on it and that's why it's not running. I would say your chances are maybe 80/20 that it's the motr that's bad. Good luck :)


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QUESTION: I have done the following.  I pulled the cover off of the blower and tapped it with a screwdriver to see no reaction.  I pulled the seat off and checked the fuses, they all seemed to be working properly.  I then checked the purple and black wires.  The purple wire was hot but i couldn't get a ground off of the black.  I also checked the cabin air filter under the hood for debris and found it to be very clean.  I located a replacement blower for my vehicle and could more than likely do the install myself.  Keeping in mind the failed ground test, what should my next steps be?  And if the blower is broken, how difficult is the install?  Thanks!

ANSWER: Well you covered your bases. But the fact that you have no ground on the black wire is a clue. The blower motor is more than likely okay. The blower control module which is where those 2 wires I had to check come from control the motor the purple wire is always hot so you have power into the blower control module and than means the fuse is okay the blowr control module sends out a varuable ground path to the motor basically a good clean ground otr not so clean which is the lower speeds to the motor. it's going to either be the control module for the motor or the dash module that controls the blower module. thre is a grey and black wire on the blower motor control module that is the signal wire from the control head to the blower module leave it connected and back probe that wire and turn the hvac blower on and off that wire the voltage should change from 5 volts off to 1.5 volts when on if it changes then the blowr control module is bad if not then the dash module is bad. It's easier to diagnose when you have a gm scan tool then using a volt meter I tried to simplify it here for you if you don't have a volt meter then this is not going to work for you a test light will not work to try this out. Hope it helps you out :)


---------- FOLLOW-UP ----------

QUESTION: I checked the blower motor and it is good, as well as the blower control module.  does this leave the only fix at the dash control module?  Is this part that actully reads out the display or the piece that allows you to select which vents your air will travel through?  
Thanks!

Answer
Okay your getting into this deep now. The control head that you push the button on sends the signal to the dash integration module and that sends the signal to the blower motor control module. I don't want you to throw parts at this these parts are EXPENSIVE and they require setup with a gm scan tool. You did all you could to diagnose it I would take it in to the dealer or a good auto reapir shop that has GM experince and let them check it out. You know what the problem isn't right now so let them give it a try. Guessing at electrical parts is never a good thing. Good luck :)