Strange Electrical Problem
Thread Starter
Racer
Joined: Dec 2003
Posts: 349
Likes: 0
From: Hong Kong
Strange Electrical Problem
I brought my 1991 vert to the garage a few days ago to have them change the radiator, and the egr valve which was acting up.
I went to pick the car up today, and when I arrived at the garage the car battery was dead. Strange I thought, so we connected another battery, and as soon as it was hooked up, the blower fan turned on, without the key in the on position. So now the blower motor runs whether or not the key is even in the car. The A/C is electronic.
I decided to check the codes, and heres what the computer said: C32 C34 C36 C38 H32 H34 H36 H38 H72 H74. And thats after a long battery reset since the power had been out for a few hours.
In the meantime I disconnected the blower plug so it wont wear down the battery. Any ideas on how to check for this problem?
Thanks in advance!
I went to pick the car up today, and when I arrived at the garage the car battery was dead. Strange I thought, so we connected another battery, and as soon as it was hooked up, the blower fan turned on, without the key in the on position. So now the blower motor runs whether or not the key is even in the car. The A/C is electronic.
I decided to check the codes, and heres what the computer said: C32 C34 C36 C38 H32 H34 H36 H38 H72 H74. And thats after a long battery reset since the power had been out for a few hours.
In the meantime I disconnected the blower plug so it wont wear down the battery. Any ideas on how to check for this problem?
Thanks in advance!
Safety Car
Joined: Oct 2007
Posts: 3,816
Likes: 0
From: :45 minutes from everywhere / E-I-E-I-O
HUH???
You had radiator service and EGR service goin' in to the shop, and comin' out, you got the entire list of GM DTC's in your computer, and a dead battery.
I think I'm missin' somethin' here. Was there a mushroom cloud when you picked your car up? Cause it sounds like EMP hit your car. Or they used the computer to visit **** sites, and you got virus.
That's pretty much the alphabet.
You had radiator service and EGR service goin' in to the shop, and comin' out, you got the entire list of GM DTC's in your computer, and a dead battery.
I think I'm missin' somethin' here. Was there a mushroom cloud when you picked your car up? Cause it sounds like EMP hit your car. Or they used the computer to visit **** sites, and you got virus.
heres what the computer said: C32 C34 C36 C38 H32 H34 H36 H38 H72 H74
Safety Car
Joined: Oct 2007
Posts: 3,816
Likes: 0
From: :45 minutes from everywhere / E-I-E-I-O
If the alternator is toast, and the car is running off of the battery, and it runs until it dies, THEN the voltage variation at the end of the battery's charge when it cuts off will set MANY DTC codes.
That's a wild guess, but I did once see it on my new GM 2002 Express van.
I don't believe your computer is toast. Charge the battery, and clear codes.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Charge the battery with the negative cable disconnected, then reconnect the neg cable. This will reset the computer and many circuits don't work right while the battery voltage is rising during charging.
Thread Starter
Racer
Joined: Dec 2003
Posts: 349
Likes: 0
From: Hong Kong
Codes are gone for now.... however the blower is still running whilst the key is out of the car. For now I have disconnected the blower plug.
Ive done some research from the forums, and so far everything seems to point at the blower module being fried.
Im not sure how that could have happened, but I guess Ill have to go and look for that part and replace it. Im just worried that if it is a short in the system, that its going to fry the new module. Anyone have any experience with this?
The A/C controls work normally, and when I push the off button, the a/c shuts off, but the blower redirects the fan to the front windshield vent and wont shut off.
Just a pain, its almost a 100 degrees here in Hong Kong with a 100% humidity, its unbearable to drive without a/c
Ive done some research from the forums, and so far everything seems to point at the blower module being fried.
Im not sure how that could have happened, but I guess Ill have to go and look for that part and replace it. Im just worried that if it is a short in the system, that its going to fry the new module. Anyone have any experience with this?
The A/C controls work normally, and when I push the off button, the a/c shuts off, but the blower redirects the fan to the front windshield vent and wont shut off.
Just a pain, its almost a 100 degrees here in Hong Kong with a 100% humidity, its unbearable to drive without a/c
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
I agree, the blower control module is defective. It has a power transistor that supplies current to the motor and is always connected to 12v. That transistor is shorted internally and supplies 12v all the time to the motor.
Heel & Toe
Joined: Oct 2006
Posts: 15
Likes: 0
From: San Juan Capistrano CA
Just had the same issue occur
I have a 93 LT1 with the same issue. The manual says to disconnect the heater and a/c control head connector then the heater and a/c programmer connector, then the blower power module. Ofcourse you have to pull apart the dash to get to the first 2. I guess I will try the blower power module first as that does not require a dash tearup.
Let me know what you found.
Thanks.
Let me know what you found.
Thanks.
Codes are gone for now.... however the blower is still running whilst the key is out of the car. For now I have disconnected the blower plug.
Ive done some research from the forums, and so far everything seems to point at the blower module being fried.
Im not sure how that could have happened, but I guess Ill have to go and look for that part and replace it. Im just worried that if it is a short in the system, that its going to fry the new module. Anyone have any experience with this?
The A/C controls work normally, and when I push the off button, the a/c shuts off, but the blower redirects the fan to the front windshield vent and wont shut off.
Just a pain, its almost a 100 degrees here in Hong Kong with a 100% humidity, its unbearable to drive without a/c
Ive done some research from the forums, and so far everything seems to point at the blower module being fried.
Im not sure how that could have happened, but I guess Ill have to go and look for that part and replace it. Im just worried that if it is a short in the system, that its going to fry the new module. Anyone have any experience with this?
The A/C controls work normally, and when I push the off button, the a/c shuts off, but the blower redirects the fan to the front windshield vent and wont shut off.
Just a pain, its almost a 100 degrees here in Hong Kong with a 100% humidity, its unbearable to drive without a/c
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1st Gear
Joined: Jul 2008
Posts: 1
Likes: 0
Strange electrical on my 93
I have the same problem on my 93. When I turn off the AC, the blower shifts to the lower vent and keeps on blowing...also, I only have use of the high speeds. From the previous blogs, it seems as if the culprit is the blower module. Has anyone verifies that yet? Also, any clues as to how to gain access? Thanks from Okinawa.
