Loss of RPM And electricity when pressing power windows

[bfunk1414]

Hello everyone,

I noticed that my car tends to lose RPM whenever I press windows switch up/down and if the lights are on, they seems to dim when it happens. Spark plugs already replaced. Anyone else had this issue? Ideas?

[80sGuy]

Battery and/or Alternator on its way out? Keep in mind that a weak or bad battery can also damage the alternator.

[bfunk1414]

Battery and/or Alternator on its way out? Keep in mind that a weak or bad battery can also damage the alternator.

If I were to take it to an autoZone or a place where the test the battery, what should I look out for?any signs or voltage that should be?

[SteveA4B7]

You can check it yourself with a multimeter/voltage meter if you have access to one, but any good battery centre, car parts store or local dealer should be able to test it better. They apply a certain load (Amps) on the battery, and measure it over a certain time. They will usually tell you if it has gone bad.

To test it yourself: Ensure car has not been started within the past 3 hours. Unlock car and open hood. Without starting-check the voltage. Red lead to positive terminal and black lead to negative. It should read more than 12VDC, while standing. Then, proceed to start the car-let it idle for a few minutes. Measure again, in same manner as before. Voltage now should measure above 13VDC. If standing voltage = below 12VDC: signs of battery going out. Running voltage below 13VDC- altenator might not be charging properly.

These tests will not apply a load on the battery, it will only check if the battery is able to keep the charge, and if the altenator is charging as it should. It's still best to have it checked out at the pro's with the right instruments.

[bfunk1414]

You can check it yourself with a multimeter/voltage meter if you have access to one, but any good battery centre, car parts store or local dealer should be able to test it better. They apply a certain load (Amps) on the battery, and measure it over a certain time. They will usually tell you if it has gone bad.

To test it yourself: Ensure car has not been started within the past 3 hours. Unlock car and open hood. Without starting-check the voltage. Red lead to positive terminal and black lead to negative. It should read more than 12VDC, while standing. Then, proceed to start the car-let it idle for a few minutes. Measure again, in same manner as before. Voltage now should measure above 13VDC. If standing voltage = below 12VDC: signs of battery going out. Running voltage below 13VDC- altenator might not be charging properly.

These tests will not apply a load on the battery, it will only check if the battery is able to keep the charge, and if the altenator is charging as it should. It's still best to have it checked out at the pro's with the right instruments.

Thanks for all the details. I'll have that checked on Sunday.

[Okedokey]

It may also be the motor. Is it on all windows?

[turbo944s2]

It may not be anything wrong with your car. All electric motors consume a large amperage when starting called inrush current.

[Okedokey]

It may not be anything wrong with your car. All electric motors consume a large amperage when starting called inrush current.

Regardless of any inrush current, no dimming should occur or RPM change.

[adam044]

In my B5 when I would push a window button my RPMS would also dip. Wouldn't matter if the window was open or closed. Did that since day one for 2 years, I didnt see any reason at all to try and figure out what it was.

[ADCS]

Both my B7 and B6 do this (B6 has xenons so no light dimming just the rpm blip). No change after installing a new Audi battery. I think they just used window motors with 1,000,000Nm of torque. It is the German way.

[adam044]

Haven't tried in the B7 yet, I'll give it a shot tomorrow morning though.

[bfunk1414]

It happanes to all the windows regardless. I still have to take a look into the battery since the car doesn't start normally during really cold Temps. All the replies have really helped. Thanks peeps!

[turbo944s2]

Regardless of any inrush current, no dimming should occur or RPM change.

I respectfully disagree with you on this. There are millions of cars all makes and models that have dimming lights when starting a power window motor. Especially at idle with other loads energized.

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[bfunk1414]

Both my B7 and B6 do this (B6 has xenons so no light dimming just the rpm blip). No change after installing a new Audi battery. I think they just used window motors with 1,000,000Nm of torque. It is the German way.

"1,000,000Nm of torque "