2004 Blower Motor Related Electrical Issue...

[cableguy83]

Hi All... thanks in advance for your help with this.

I have a 2004 Impala.... overall, love it. Lately though, the battery has been draining (it's basically a new battery) to the point that the car is completely dead. I checked the alternator... all seems to be fine there.... the battery checks out once I use a battery charger to bring it back up to speed.

I then hooked a multimeter up to it in series while it was off to see if there was any parasitic battery drainage... there WAS.... it showed almost 1.2 amps of discharge. I went to pulling fuses, and the amperage went to about 10 milliamps (good) once the 30 amp fuse for the blower motor was pulled.

Does anyone have an idea as to what might be happening here? What on that circuit would be pulling 1ish amps while the car is turned OFF?

Some have mentioned it might be the blower motor processor control going out OR the climate control head unit going out. I don't have a wiring diagram or service manual so I don't know where to look exactly... I know it would be somewhere beneath the passenger side dash, no?

Any help would be great.... thanks for your expertise.

Peace and thanks,
cableguy

[waterkeeper03]

Originally Posted by cableguy83

Hi All... thanks in advance for your help with this.

I have a 2004 Impala.... overall, love it. Lately though, the battery has been draining (it's basically a new battery) to the point that the car is completely dead. I checked the alternator... all seems to be fine there.... the battery checks out once I use a battery charger to bring it back up to speed.

I then hooked a multimeter up to it in series while it was off to see if there was any parasitic battery drainage... there WAS.... it showed almost 1.2 amps of discharge. I went to pulling fuses, and the amperage went to about 10 milliamps (good) once the 30 amp fuse for the blower motor was pulled.

Does anyone have an idea as to what might be happening here? What on that circuit would be pulling 1ish amps while the car is turned OFF?

Some have mentioned it might be the blower motor processor control going out OR the climate control head unit going out. I don't have a wiring diagram or service manual so I don't know where to look exactly... I know it would be somewhere beneath the passenger side dash, no?

Any help would be great.... thanks for your expertise.

Peace and thanks,
cableguy

seems the hvac in these cars are prone to some issue. i have been dealing with blown resistors for a while now and I'm just getting to the source. seems that these blower motors throw resistance against the speed resistor itself and cause shorts leading, in some cases, all the way back to the ignition module. my car is an 04, with the 10 stage speed switch, but I believe it's only a 20a fuse in these cars.

one symptom of a bad blower motor relay has been that the blower motor runs continuously. it may be possible that yours is bad and draining the battery.

[cableguy83]

I found that when I unplug what I believe to be the "blower motor control processor" the ammeter shows zero. So... that must be the problem piece. Now... the question is... where to get a new one? I would imagine that is the right fix... no? The seem to be a bit elusive when I search for them online.

Thanks for your input... good day!

~cable

[SierraK1500]

Heres one for you......take the bottom panel off the dash under the glove box, and pull the harness connector from the Resistor assy OUT OF THE MOTOR!

No more dead battery and you can get it fixed. The resistor has nothing to do with the motor running with the key off.

The relay for the blower is under the hood. Look in the top fuse box on the passenger side. Replace that relay they are under 10 bucks. Junkyard is 5.00
Those boxes are mounted on the strut support.

The 30 amp fuse if it blows will render the whole system dead as far as the blower goes.