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Discussion Starter #1
I have a 97 Catera. When I turn the ignition off the power stays to the
air condition/heater controls. I can turn the air off..but there is still power
to the controls even though the car is turned off. The outside temperature reading also stays on. When I remove the fuse that controls these functions then put it back in everything returns to normal.
With the constant power to the controls it drains the battery. I have taken car
in and the mechanic seems to think it is the ECM..........any ideas?
 

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1968 Cadillac Sedan deVille, 1994 Chevrolet G20
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Does anything else (power windows...) stay on too? If they do, it might be that retained accessory power acting up. And as far as computers go, it would be the BCM if it was any of them causing trouble.
 

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Discussion Starter #3
DaveSmed said:
Does anything else (power windows...) stay on too? If they do, it might be that retained accessory power acting up. And as far as computers go, it would be the BCM if it was any of them causing trouble.
the radio stays on but that turns off when the door opens

everything else is off............
 

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Try resetting your computers. Disconnect the battery for about an hour, then reconnect it and see if it is still acting up.
 

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Discussion Starter #5
DaveSmed said:
Try resetting your computers. Disconnect the battery for about an hour, then reconnect it and see if it is still acting up.
I have done this, in fact I have recently replaced the battery.

Anything else I could try

Rick
 

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Although it is looking like the BCM, I would first try to get a factory service manual. That will give you the wiring diagrams, and I would check any power leads to the BCM. Make sure they are not showing voltage whne they shouldn't. I would also check the BCM itself. Look for anything that would cause a short between a constant power source and the trigger lead.
 

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Discussion Starter #7
DaveSmed said:
Although it is looking like the BCM, I would first try to get a factory service manual. That will give you the wiring diagrams, and I would check any power leads to the BCM. Make sure they are not showing voltage whne they shouldn't. I would also check the BCM itself. Look for anything that would cause a short between a constant power source and the trigger lead.
Could you please tell me what the BCM is...I know what the ECM is....but what
does the BCM stand for. I have found some ECM.s but the sites I have gone to
do not list a BCM...

thanks Rick
 

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Discussion Starter #8
I have Checked out the ECM, BCM, the key ignition and I am still unable
to find the problem. The main problem seems to be the constant power to
the A/C and heating controls. Every thing else turns off properly. It seems
like it is a relay that will open but not close when the key is turned to the
off position.....yes/no? any other idea or thought

thanks

rick
 

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Check the relay..... I bet one is stuck open....

Swap one for a known good one..... They are the same as long as they have the same diagram on the plastic cover thing and are the same color.
 

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Discussion Starter #10
elwesso said:
Check the relay..... I bet one is stuck open....

Swap one for a known good one..... They are the same as long as they have the same diagram on the plastic cover thing and are the same color.
I have pull every relay and every fuse I could find. And still nothing, I have check the BCM & the ECM. I have pulled the heater a/C control from the dash
and checked all the wiring. What the bottom lin comes to is that when I turn the
key off I still have constant power to the heater a/c control and unless I pull the
fuse from # 12 in the fuse box the control stays on. I must be missing a relay
somewhere ...but I have no idea where it could be. any ideas? The problem seems to be from the fuse to the heater a/c control ....

rick
 

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Here is where it gets interesting. I highly recommend a factory service manual. Anyway, see if you can determine if that fuse is supposed to be hot at all times, or ignition controlled. Then get a test light and make sure it is acutually functioning correctly. I have seen fuse boxes short out and make radios stay on constantly. If the circut is supposed to be hot at all times, find out what it goes to. It will probably end up going to the BCM or some other computer. From there, you will definitely need a factory service manual to find out the power leads going into the BCM. One of them may have enough voltage going through it from a dirty contact somewhere to keep it on.
 

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Discussion Starter #12
DaveSmed said:
Here is where it gets interesting. I highly recommend a factory service manual. Anyway, see if you can determine if that fuse is supposed to be hot at all times, or ignition controlled. Then get a test light and make sure it is acutually functioning correctly. I have seen fuse boxes short out and make radios stay on constantly. If the circut is supposed to be hot at all times, find out what it goes to. It will probably end up going to the BCM or some other computer. From there, you will definitely need a factory service manual to find out the power leads going into the BCM. One of them may have enough voltage going through it from a dirty contact somewhere to keep it on.
A FSM is not very easy to find.....as to the fuse, in the book it is listed for the
Hazard, I am pretty certain the fuse is always hot. When this problem first started I was pulling into our neighbor hood and the car started doing crazy thing, the transmission wouldnt shift properly the airbag light came on (is still on) the service engine came on and the controls for the heater and a/c went
off. I pulled over and shut the car off. When I restated the car everything
went back to normal. I noticed the current problem when I turned
off the car at home and the a/c remained on. At this time I disconnected the
battery. Then I started working on the problem and I found fuse 12 controlled this problem. So if I just pullled the fuse it shut the a/c control off
then I would just put fuse back in and everything was fine until I started the
car then the process started over. I currently have a toggle switch hooked
up so I can just turn this off when I turn off car. then turn back on when
I restart the car. Everything else on this circuit works fine except for this
direct power to a?c heater. If I dont use the toggle switch the battery
runs down and car wont start.......I want to sell the car but dont feel right
selling it the way it is. any other help or ideas would be appreciated.

thanks

rick:banghead:
 

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Hmm. It's REALLY starting to sound like one of the computers is having problems. I'm not sure if you can pull codes through the dash of a Catera, but it's worth a try. If you can't then go to AutoZone or someplace similar and get your codes read there.
 

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Discussion Starter #14
DaveSmed said:
Hmm. It's REALLY starting to sound like one of the computers is having problems. I'm not sure if you can pull codes through the dash of a Catera, but it's worth a try. If you can't then go to AutoZone or someplace similar and get your codes read there.
does anyone know how to pull codes through dash of 97 Catera..........
Please let me know
thanks rick
 

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You can try pushing OFF and WARMER at the same time with the Ignition on. Hold them in untill the car does a light check. If this does not work, then it might not be able to display the codes through the dash.
 

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Since you don't have a factory service manual, I would suggest going to your local library and looking at their Alldata or Mitchell reference material for schematics and instructions for diagnostics and troubleshooting. Take a pencil and tablet, because you'll be writing all sorts of information down.
 
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