AC/heater blower stopped working

Tiny
MERMIATWD
  • MEMBER
  • 1992 BUICK LESABRE
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 75,000 MILES
Car listed above is a Limited. The AC/Heater blower fan was working perfectly. Turned car off for about 2 hours and when restarted vehicle A/C fan just did not come on at all. I can't seem to find a specific fuse for this blower fan in any of the fuse boxes. Is there an in line fuse in the fan's wiring or on the fan itself? Or am I just not looking for the fan fuse in the right places?
Friday, June 11th, 2021 AT 1:50 PM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,128 POSTS
Hi,

There are a couple of fuses that need to be checked. If you look below, pic 1 shows the locations of the blower motor relays. If the fan doesn't work at any speed, it isn't likely that it's a relay because you have two different ones. One is for high speed and the other the lower speeds. I don't think both would fail at the same time.

So, that leaves a blown fuse, faulty ground, bad motor, or other wiring issues.

So, start by checking the fuses. Pics 2 and 3 are the wiring schematic for the blower motor. I highlighted the fuses to check. If the fuses check good, confirm there is continuity to ground via the blower motor. If there is both power and ground to the motor and it doesn't work, replace the motor.

If there is ground and no power, then check the relays. Here is a link that explains how to test a relay. Also, a link that explains how to test wiring.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

https://www.2carpros.com/articles/how-to-check-wiring

If you find the blower motor is bad, the remaining pic explains how to replace one. Follow the numbers for sequence. Also, here is a link that explains in general how it's done. It's a little more detailed.

https://www.2carpros.com/articles/blower-fan-motor-works-on-high-speed-only

Let me know if this helps or if you have other questions. Also, note that I am basing this on the fan doesn't work at any speed. If that is incorrect, let me know what is happening.

Take care,

Joe

See pics below.

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Friday, June 11th, 2021 AT 10:58 PM

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