The A/C blower motor would not shut off and now will not turn on?

Tiny
CADILLACKID247
  • MEMBER
  • 1995 CADILLAC ELDORADO TOURING
  • 4.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 50,000 MILES
The A/C blower motor worked fine but rarely would turn off but always came back on a couple seconds later. Lately it didn’t come back on, so I replaced it. The next day I drove my car for a little while and it wouldn’t turn off even when I took my keys out for the car. I disconnected my battery and it shut off of course. But now that I’ve reconnected the battery it won’t turn back on at all. It could be that it was an AutoZone part so maybe I need to go pull an OEM one, but I don’t know. Any advice helps.
Sunday, August 27th, 2023 AT 3:49 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

First, check fuse 4 to make sure it is good. See pics below.

If the fuse is good and has power, then I need you to the blower motor and check the red wire for power. It should be present at all times. If there is power, check the black wire in the connector for continuity to ground. Also, at the controller will be a black wire with a white tracer. Check it for ground as well. Here is a link you may find helpful:

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

Let me know what you find. Keep in mind, there should be power at all times at the motor itself. A ground path is provided by the controller to complete the circuit.

Simply based on what you described, I have a feeling it is the controller that has failed, but we need to test first.

Let me know.

Joe

See pics below. The last two pics show the right maxi fuse box location and fuse.
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Sunday, August 27th, 2023 AT 8:52 PM
Tiny
CADILLACKID247
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  • 3 POSTS
Okay, so first of all thanks for your help joe, I do not know what I’d do without you. Also, I am new to everything electrical I’ve never done any of this before, so your advice is appreciated a lot. Sorry I haven’t got back to you sooner it’s been a crazy time with all the floods. I checked the fuse, and it seems to be good. The red wire for power I also checked, and it seemed to have consistent power but I’m going to go back to messing with it in a second. It was just annoying to get in the right spot to read it in the connector. I'm pretty sure it’s fine though. So, I was going to ask how I test that black wire for ground with the multimeter. Also, I’m assuming by controller that’s what people are calling the control module. Do you have any clue where that would be?
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Sunday, September 3rd, 2023 AT 3:44 PM
Tiny
CADILLACKID247
  • MEMBER
  • 3 POSTS
After a little looking people are saying that in my model year the controller is on the back of the blower so in that case it would have been swapped out when I changed the blower. And also, I checked the red wire extensively and it’s giving me enough volts but then every handful of seconds I see it go down to only like 5-7 idk if that’s a problem but it just flashes that for a portion of a sec and then goes back to like 14 or whatever it is.
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Sunday, September 3rd, 2023 AT 5:08 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Hi,

That is an interesting one. If it is changing voltage, either we have a loose connection, a corroded connection, or a damaged wire. You should have battery voltage to it at all times.

Does the voltage change if you move the wire around?

Let me know.

Joe
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Sunday, September 3rd, 2023 AT 9:30 PM

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