Brake pedal slows blower motor

[Buickagain]

Any idea why? The blower motor slows as the brake pedal is pressed. It speeds up again when the pedal is released. It also speeds up again once the brake pedal is fully pressed and tge car stopped. Any idea why.

 

[Kyosha]

Check on the alternator, it sounds like the car is not supplying enough power when under a load.

 

[Buickagain]

Check on the alternator, it sounds like the car is not supplying enough power when under a load.

Thank you.

 

[Mad_Coachman]

Also make sure your battery terminals are free of corrosion. Even though our batteries are under the rear seat they are not immune from corrosion.

 

[Buickagain]

Also make sure your battery terminals are free of corrosion. Even though our batteries are under the rear seat they are not immune from corrosion.

Thank you.

 

[imidazol97]

Check the battery negative terminal at the floor pan for corrosion.
I'd remove the negative cable and clean the contacts then retighten them.

 

[BuickGirlFromMars]

Run the car, turn it off, come back 15 minutes later and press the pedal to floor , then let up
do it again

You should get a couple full depressions from the reservoir of vacuum. I would also replace the check valve and grommet on the booster just because of age to ensure they are good again too

 

[Buickagain]

Run the car, turn it off, come back 15 minutes later and press the pedal to floor , then let up
do it again

You should get a couple full depressions from the reservoir of vacuum. I would also replace the check valve and grommet on the booster just because of age to ensure they are good again too

Thank you.

 

[BuickGirlFromMars]

Thank you.

So any update.. you have thanked us but if you fixed or still are scratching your head we could proceed with what you have to say. if you havent tried yet, let us know what you find.

 

[Buickagain]

The problem seems to have been solved by replacing the blower motor.

 

[BuickGirlFromMars]

The problem seems to have been solved by replacing the blower motor.

The blower motor isnt hooked up electronically to the brake switch or the vacuum booster.
Unless there was electronically an issue where the motor was pulling too much amps and the performance was not 100% and thus the alternator demand had to accomodate or the wiring had excessive resistance in the connections, you didnt fix the cause by replacing.

I would suspect the reason is not directly related but it was related to the process around a possible good part but the things touched in the middle. I would have measured how much amp draw the old one had and then compare your new one at the same high speed and see if that varied. not necessary now, but if you saw a big jump, that was probably your reason. could possibly mean your cars alternator is getting tired too but you can go get a battery test and alt test at autozone if you want to be safe on that. Drive a bit so your battery is fully charged and then try that. Your alternator isnt the highest outputting at 105 amps but its not nothing either. Heated seats, defrost easily can chew that down quick. Infact, battery load management may take some of your fan speed just because its expecting engine RPM to both decrease and then car may be at a point where it would discharge and then its shedding a load to keep it powering more important or just monitor battery health. Because of the distance of your battery from the fan, alternator, you should almost check the charge wire and battery connections and the lug on the alternator for corrosoion to be safe. Fuse box under hood is probably the one that powers the fan, but I cant be certain(backseat possibly) i would check the positive lug on those for corrosion too.

i dont think anything is broken but if you have the means to preventative check or maintain it could save future headache 🙂