My fan keeps running?

Tiny
ISIDRO805
  • MEMBER
  • 2001 CHEVROLET BLAZER
I would like to know what is wrong with my vehicle when the AC fan keeps running while the vehicle is off. I have turned off the knobs inside but he fan is still on even after I turn off the engine. I have taken the battery cable off to see if this will stop the fan from running but when I hook the cable back up to the battery the AC fan turns right back on. What do I need to do to fix this?
Saturday, May 10th, 2008 AT 2:32 PM

12 Replies

Tiny
OBXAUTOMEDIC
  • MECHANIC
  • 3,711 POSTS
It is most likely your A/C Fan Relay. Find it and pull it out. If there is another relay that has the same numbers on it move it to the a/c spot if it stays off then replace the relay.
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Monday, May 12th, 2008 AT 5:50 PM
Tiny
MIKE1987
  • MEMBER
  • 1 POST
  • 2001 CHEVROLET BLAZER
Heater problem
2001 Chevy Blazer 6 cyl Four Wheel Drive Automatic

hey car pros I have a 01 chevy blazer and the heater fan motor keeps running and if you pull the fuse it stop or you can turn the knob and it does nothing I checked the module on the heater box in the engine compartment is it the controls on the inside thanks alot guys
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Monday, December 28th, 2020 AT 11:00 AM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check to see if you have a broken ground wire going to the body causing this. It sounds like it doesn't have a good ground and when you shut the switch/ignition off, it still runs. Also make sure that there are no burnt wires together at the heater switch.
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Monday, December 28th, 2020 AT 11:00 AM (Merged)
Tiny
DUCK7264
  • MEMBER
  • 6 POSTS
  • 1997 CHEVROLET BLAZER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 177,000 MILES
Hello,
I have a 1997 chevy blazer s10 4.3L automatic 2 whl dr. The problem I am having is that whenever the ignition is in the "off" position the blower motor for the heater/ac stays on and the electric windows are still working. I am having trouble keeping the battery charged also. I just bought a new battery last week and is already dead. Have been told sounds like an ignition switch problem but I just had a new put in about a year ago. Any info on this would be appreciated.

Thanks,
Glenn
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Monday, December 28th, 2020 AT 11:00 AM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Welcome, thanks for the donation, as far as the blower motor, can you tell what speed is blowing? There is a blower relay, my info says center rear of engine compartment, probably on the firewall. Does it still run with the hvac controls turned off?

Voltage for high speed is hot all the time, but, continuity only when relay is energized. When the relay is not energized, there is continuity for the lower speeds. Voltage for coil side of relay comes from the hvac control. Voltage to the control assembly goes hot when you turn the key on. If the hvac is turned off, even if there is voltage shouldn't matter? No continuity till you turn on controls.

I didn't think to look at power windows. That circuit may go hot when you turn on the key, but, even if the circuit stays hot, as long as the windows aren't being operated, nothing happens. You may have more than one problem?
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Monday, December 28th, 2020 AT 11:00 AM (Merged)
Tiny
DUCK7264
  • MEMBER
  • 6 POSTS
Ok the blower fan cuts off if I turn the hvac controls to the off position. I have it set on the highest setting, but the windows still work even if have the hvac controls off. If it does'nt matter if they work or not why is my battery draining this? I thought that maybe it was a "constant hot" even if they were in the off position. Also, when the ignition is turned all the way back everything cuts "off" then, but you can't get the key out.
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Monday, December 28th, 2020 AT 11:00 AM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Hi, I thought the blower motor was draining the battery, you said it ran all the time? The power windows only use voltage when you hit the switch. If you want to check feed circuits to and from the ignition switch, i'll help anyway I can.

With everything turned off, what is the amp draw, check at battery. Battery has a full charge and charging system is good?

Pull the power window circuit breaker, 30 amp, I believe, with the key turned off, use a testlite see if circuit is hot? Shouldn't be hot unless key is on. Also pull heater/ac fuse 20 amp, use testlite, everything turned off. That circuit should not be hot unless key is on. Those circuits get voltage from the same ignition circuit, orange wire, ignition switch.
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Monday, December 28th, 2020 AT 11:00 AM (Merged)
Tiny
DUCK7264
  • MEMBER
  • 6 POSTS
No I apologize. The fan motor runs when the controls are on, but you can turn the control to the "off" pos. And it will shut off. As far as the amp to the battery, I don't have a meter so. Sorry about any miscommunication.
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Monday, December 28th, 2020 AT 11:00 AM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
I think I misunderstood, Those circuits shouldn't be hot unless the key is on. Your correct, I believe it is the ignition switch. Have a good day
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Monday, December 28th, 2020 AT 11:00 AM (Merged)
Tiny
YNNEK1991
  • MEMBER
  • 1 POST
  • 1996 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 90,000 MILES
I am having problems with my heater fan. Sometimes it works and other times it runs till I shut of the vehicle. When I get back in to turn on the heater it seems like the fan does not want to work until I drive around for a little bit. Can you help me with this problem. I don't want to take it into a mechanic if it is something easy to fix Thank you.
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Monday, December 28th, 2020 AT 11:07 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the blower motor relay and the HVAC control assembly
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Monday, December 28th, 2020 AT 11:07 AM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Another thing to check is see if the blower motor it self is causing the problem. When it stops, tap on it with the handle end of a screw driver and see if it starts to work
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Monday, December 28th, 2020 AT 11:07 AM (Merged)

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