Buick A/C Problem

I have a 1992 Buick LeSabre Limited with an odd problem. It has the dual climate control system. The blower does not appear to blow air as hard as it used to. Therefore, the passengers in the back are not getting the cool. I recently checked the GM shop manual for this vehicle out from my local public library. I have made all of the checks the Electrical Systems Manual (ESM) recommends. Everything appears to function properly as far as the ESM is concerned, except for the diagnostic mode number the HVAC Programmer spits out for the blower speed (Should be 128). As I recall, the number was way low (About 76). I checked the actual voltage and current of the motor. It is getting full battery voltage, and is drawing just over 16A. The outside air and all other valves the HVAC Programmer operate seem to be working normally. With an ambient air temp of 85 degrees the vents are discharging 48 degree air. I’m at a loss, and wonder if you might be of assistance. I am just shy of taking this to a professional, but really do not have the extra money to pay them, especially if there is no problem. Thank you in advance for any advice.

Ray M.

I did forget to mention that the top 2 bars on the fan speed indicator make no difference in speed.

I would suspect that your blower motor is failing. 16A sounds too high. Does it rotate freely if you spin it by hand? If not, the bearing may be failing.

Thank you for your answer. I will try what you suggest this evening. As I additionally mentioned above the top 2 bars on the fan speed indicator made no difference in speed. Also, they made no difference in voltage applied to the motor.

Do you happen to have an idea of what a normal current draw would be? This particular circuit is fused at 30A.

Sorry, I’m not to up on GM, but maybe someone else will chime in.

Have you thought that perhaps the ground side is what is regulated? make a high resistance to ground and you will drop the voltage accross this resistance, thus slowing the motor. High speed is direct to ground (still via the resistor block).

Of the many.many GM blower motors I have replaced (probably close to 75) none have been due to a measureable over amp condition, most have been due too complaints of a slight squeak that can be heard at low speed, some have been at owner insistance that the blower motor took the resistor out, none was a measurable over amp condition.

Sorry, I assumed that the OP was measuring voltage across the two blower connections.

My vote is for a dragging blower motor; 16 amps sounds excessive to me.

Comparing the 16 amp draw to the 30 amp fuse omits a few things. One is that there are likely other things drawing from that same fuse and the blower and everything else will also have a current surge when first activated.
The surge is true of any electrical item no matter if it’s auto, home, aircraft, or ocean liner and the fuse should be capable of handling the surge and then some.

A few weeks ago my wife said the blower blinked out several times on our Lincoln even though it worked fine when I checked it. (no noise, moving plenty of air, etc.)
A current test showed the following.
Blower installed in the car with wheel running on HIGH; approx. 25 amps. Ouch.
Blower removed with wheel in place on HIGH; approx. 8 amps.
Blower with wheel removed on HIGH; 3 amps.

Shows the huge difference in current draw when even a small amount of load is applied.
In this case, no EATC codes existed and a blower motor change cured the problem.