Hopefully someone can help me...

I have a 95 Saturn SL1. The blower fan turns on randomly when the car is off. It seems to be completely random, usually a few hours after the car is shut off. It'll happen maybe a couple times a week, then won't for a week or two. You can hear the fan from outside the car, and it blows air inside the car as if the fan was on high. If you put the key in and turn to the on ac or on position, it stops. It's killed my battery a few times.
I've replaced the cooling fan relay and the cooling fan sensor. The sensor was cracked, and I really thought that would fix the problem, but the next day it did it again.
Read somewhere that someone replaced the battery and it fixed a bunch of problems like this, but wanted to know if anyone had any ideas first..

Thanks for your help,
Mike

there is a module a dealership can install to create this "afterblow" feature, chances are somewhere at sometime it was installed on your car, it is designed to prevent mold build-up on the evaporater core after the A/C is used. i bet if you turned off the A/C for a few days, the fan won't kick on. if i remember correctly if certain parameters are met, the fan will turn on 5 minutes after shut down and run for 45 minutes to a hour. if this is the case the dealership can disable it, but frist i would check your battery, as i don't think it should die that easy.

Possibly this module was installed and it is defective? The blower will run for hours before the battery dies. There have been a few mornings that it had been on when I havent run the car since the afternoon before. Is this a module that I can (easily) remove?

Thanks
Mike

there is a module a dealership can install to create this "afterblow" feature, chances are somewhere at sometime it was installed on your car, it is designed to prevent mold build-up on the evaporater core after the A/C is used. i bet if you turned off the A/C for a few days, the fan won't kick on. if i remember correctly if certain parameters are met, the fan will turn on 5 minutes after shut down and run for 45 minutes to a hour. if this is the case the dealership can disable it, but frist i would check your battery, as i don't think it should die that easy.

wait a second, after rereading your thread i'm not sure we are same fan. the radiator fan is under hood and controled by the ECT sensor and cooling fan relay. the blower motor is the fan for the interior vents, and is controled by the HVAC control panel or the afterblow module. i beleave you are talking about the later correct?

assuming so: i think a bad afterblow module is possible, i will need to check a few TSBs and get back to you. does this only happen on high? no matter what the fan speed is set at? next time it happens try pulling the blower relay located in the fuse block behind the passiger kick panel to stop the fan.

actually I'm not really sure which one it is... I can hear the fan from the outside, but air is definitely blowing into the car. Would the radiator fan being on cause air to blow through the vents? It happens no matter what setting the fan is on, usually I shut it off when I shut the car off. I will try pulling the blower relay next time I catch it, if it doesnt stop it I will try pulling the cooling fan relay. I think it might be the cooling fan because the car seems to run hot when parked or in traffic. It actually cools off when I turn the A/C on (I assume an aux fan comes on when you run the A/C). Like I mentioned, I replaced the cooling fan relay and temp sensor, so I'm definitely stumped.

Thanks again

wait a second, after rereading your thread i'm not sure we are same fan. the radiator fan is under hood and controled by the ECT sensor and cooling fan relay. the blower motor is the fan for the interior vents, and is controled by the HVAC control panel or the afterblow module. i beleave you are talking about the later correct?

assuming so: i think a bad afterblow module is possible, i will need to check a few TSBs and get back to you. does this only happen on high? no matter what the fan speed is set at? next time it happens try pulling the blower relay located in the fuse block behind the passiger kick panel to stop the fan.

the cooling fan not comming on when hot may be a bad ECT sensor.

i found the TSB, here are a few quotes.

Subject: Odor from A/C at vehicle start-up
Cause: mircobial growth on the evaporator core caused by moisture present from normal A/C operation
Correction: remove debris, disinfect evaporator, and install delayed blower motor control module

delayed blower motor control module(afterblow module) operation - The delayed blower motor control module will not affect normal A/C or blower motor operation, However, the delayed blower motor control modulewill activate the blower motor on high speed for approximately five minutes, if the A/C compressior clutch has been continuously engaged for four minutes or more. the delayed blower motor control module will wait approximently fifty minutes after the ignition is turned off before activating the blower motor. it is during this blower run time that condensate, that causes microbial growth, is remove from the evaporator core. the blower will be turned on with NO driver input if the conditions as stated above are met. the air rush sound created by the blower motor is noticealbe from outside the vehicle.

ok, if you do have the delayed blower motor control module installed it would be installed inside the driver side kick panel, opposite of the underdash fuse box, attached by velcro to the top center of the heater duct. and guessing from the photo it is a little smaller then a deck of playing cards. also, if it is a defective module, when it blows with the key off, removing the BODY 10amp fuse should power down the module.

if it is found the module is not installed or not at fault, then you most likey have a intermiddent short to power. please let me know and i will help you from there.

I know its been a while since this thread, but I have an update for this. The problem (blower turning on when car is off and killing battery) seemed to stop after I replaced the battery. It recently started to happen again and I remembered reading a reply about an aftermarket blower module.

You were right, it was this module. I disconnected it and the problem stopped. I assume that this device was defective and instead of turning on the blower for 5 min, it would stay on until the battery died.

Thanks sierrap615!

By removing the BODY 10 AMP fuse fix the blower fan from cominig on or does that fuse control other things?