A Strange problem - Power Window
09-02-2022, 09:16 AM
#1
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Thread Starter
A Strange problem - Power Window
Yesterday afternoon, I went to start my '84 Trans AM & the battery was click click on the starter - nearly dead battery. I placed a charger on it and let it charge for several hours.
It charged up & no problem starting the engine.
I attached my digital meter to the battery to check for unusual voltage drop. I could see the gauge lower regularly 0.01 volts, slowly.
I removed the connection to the alternator to eliminate it as the current drawer. It was not.
For overnight, I reinstalled the charger for a full recharge. This morning I began the investigation again.
With the battery cables removed, voltage remained constant, no drain, for 10 minutes. I reattached the cables.
I remembered from the past, that these window switches or motors could cause problems.
I had left the driver side window down about 1/2" four days prior to the battery problem.
Powered up the window fully. Checked the meter. No voltage drop.
Powered down the window fully Checked the meter. No voltage drop
Out of curiosity, I powered down the driver's window part way & checked voltage. I watched my meter for several seconds & the voltage began to drop regularly by 0.01 volts, slowly, over 30 seconds.
I tried the passenger side window with the same tests & there was no voltage drop.
I believe that I have diagnosed the problem.
Prognosis?
Now, can someone explain to me why, in the door, the motor is drawing current when the window is not fully up or down? Is there a sensor, in the door, that monitor's the window position which should function properly whether is fully up or down or part way???
OR could the power window switch somehow be applying a bit (residual) of power to the window but not sufficient to power the motor when the window is part way down?
Maybe I will pull the console power window switches & test.
It charged up & no problem starting the engine.
I attached my digital meter to the battery to check for unusual voltage drop. I could see the gauge lower regularly 0.01 volts, slowly.
I removed the connection to the alternator to eliminate it as the current drawer. It was not.
For overnight, I reinstalled the charger for a full recharge. This morning I began the investigation again.
With the battery cables removed, voltage remained constant, no drain, for 10 minutes. I reattached the cables.
I remembered from the past, that these window switches or motors could cause problems.
I had left the driver side window down about 1/2" four days prior to the battery problem.
Powered up the window fully. Checked the meter. No voltage drop.
Powered down the window fully Checked the meter. No voltage drop
Out of curiosity, I powered down the driver's window part way & checked voltage. I watched my meter for several seconds & the voltage began to drop regularly by 0.01 volts, slowly, over 30 seconds.
I tried the passenger side window with the same tests & there was no voltage drop.
I believe that I have diagnosed the problem.
Prognosis?
Now, can someone explain to me why, in the door, the motor is drawing current when the window is not fully up or down? Is there a sensor, in the door, that monitor's the window position which should function properly whether is fully up or down or part way???
OR could the power window switch somehow be applying a bit (residual) of power to the window but not sufficient to power the motor when the window is part way down?
Maybe I will pull the console power window switches & test.
Last edited by 72buickgs; 09-02-2022 at 10:01 AM.
09-02-2022, 10:36 AM
#2
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Car: 1990 GTA
Engine: 5.7
Re: A Strange problem - Power Window
Hi there,
I'm sorry to hear you are having troubles.
The 12V power for the window switches is tied to your ignition wire (Switched Power). With factory wiring, your windows should not be able to draw any power from the battery, once the ignition has been turned off.
There are also no sensors within the door. I would check your window switch plug with a voltmeter, to see if it is receiving any voltage while the ignition is off.
If there is voltage at the window switch, while the ignition is off, you will need to trace back your wiring to find out why it has power, when it shouldn't.
The way the factory switches are designed, as they age, they could potentially begin to function less smoothly. After pressing and releasing the switch, the switch could be only partially disconnecting from the motor. This could cause the switch to try sending small amounts of current through the motor, slowly reducing battery life.
I hope this helps.
I do offer aftermarket switches on my website, if you are ever interested in an upgrade.
https://bravetech.ca/
Braven
I'm sorry to hear you are having troubles.
The 12V power for the window switches is tied to your ignition wire (Switched Power). With factory wiring, your windows should not be able to draw any power from the battery, once the ignition has been turned off.
There are also no sensors within the door. I would check your window switch plug with a voltmeter, to see if it is receiving any voltage while the ignition is off.
If there is voltage at the window switch, while the ignition is off, you will need to trace back your wiring to find out why it has power, when it shouldn't.
The way the factory switches are designed, as they age, they could potentially begin to function less smoothly. After pressing and releasing the switch, the switch could be only partially disconnecting from the motor. This could cause the switch to try sending small amounts of current through the motor, slowly reducing battery life.
I hope this helps.
I do offer aftermarket switches on my website, if you are ever interested in an upgrade.
https://bravetech.ca/
Braven
09-02-2022, 10:43 AM
#3
Re: A Strange problem - Power Window
There's no sensor on our windows/motor/switch/wires. My first guess would be the motors. Maybe they're a little gummed up from all the years. Maybe they're sticking (stiction, if thats a thing for electric motors). Leaving some mynute load on the battery. Or window switch could be sticking, swap them right to left and see if the problem moves with the switch.
09-02-2022, 12:57 PM
#4
Member
Thread Starter
Re: A Strange problem - Power Window
next step would be to swap switches left to right & vise versa.
09-03-2022, 12:15 PM
#5
Member
Thread Starter
Re: A Strange problem - Power Window
I decided to give the battery a full charge overnight with the battery cables removed. This morning, with my meter & with the charger removed, I checked the voltage & watched it drop & drop. Solution - time for new AC Delco battery.. All is well now at $200 cdn..
09-03-2022, 03:15 PM
#7
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Thread Starter
Re: A Strange problem - Power Window
I have no idea as to the age of the battery. I would guess 4 years as the car did not come from BC (where orig owner lived & died) until 2017 when it arrived in Quebec for his daughter. Probably new battery then. I located the front hold down part under the battery. I had used many washers to hold down the battery before finding the unit.
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