Hi
A4 1996 2.8
OK this might sound strange, or maybe not you guys judge. Normally when I do turn on my A/C the motor vibrations change and I can feel it within the car, I would consider this typical behavior. I did notice something today I never noticed before, when I do turn on the car light + fog light. I.e. when the blue led light on the dash board illuminates the motor changes it's sound and vibrations as if some more load has been added to it. The change in sound and vibration is minimal however big enough to be noticed. Well there is a slight change in motor noise and I can feel the change in vibration through the arm pad. I did try this while the car was idle and not while I was driving.
I am worried because lately there I had a lot of problems related to rpm "always high" and in the end it turned out to be a wire issue and once the wires where changed the rpm issue was solved. Could this be related ?
Or is this just a typical behavior ?

 

try changing the motor mounts and snub mount. it is related but you shouldn't that much shaking. maybe a little bit in the steering wheel but not the armrest

 

Well the arm rest itself does not vibrate but if I do put my hand on it I do feel the vibration change. I did have motor mounts changed recently, but not the snub mounts.
Is this something I should be worried about ? Or would this still be considered normal ? ...hmm..one other thing..the light switch to the left behind the steering wheel, did stop working only the blinkers used to work, I wanted to have it replaced but they said it can be fixed so they did fix it however now the light only works if I do pull the light switch up very fast. I will change the switch, however is this related to my problem or is my problem something of a totally different nature ?
Thanks

 

any electrical product of the car is going to put more strain on the alternator.. Did you think about checking your belts? Maybe even a fan clutch?... It might not be related to your foglights but rather something that is a coincidense with that button. If its minimal I would say your car is just getting older... If it bothers you that much.. check routine maintenance..... Shrug...

 

When you feel/hear extra load on the engine when using electronics that can be a sign of a weak ground. If it's dramatic when you turn the ac on it could be an over tensioned ac belt or engine mounts for sure. Get crafty with a multimeter.

 

Just for the hell of it, get some braided steel cable and make a few extra grounds for the battery. I did this - ran from the airbox support bolt on the passenger fender, over to the fuel rail bracket on the passenger side of the engine (under the beauty cover), over and around to a mounting bold beneath on the ABS controller, to the battery negative, and back to the original airbox support bolt. Effectively I added several ground points for the battery. The car seems a bit smoother as a result - the worse off your battery ground is, the more improvement this can make.

 

Had to reply to a Linux enthusiast even if I can't add anything. before adding the extra grounds I would load test the battery both running and not. that way you can isolate battery or alternator. hope this amkes sense I am drunk as hell right now.