Lights dim when i drive? WHY?

[jesse]

Sometimes when i am driving at night my headlights will dim for a second them go back to normal. Is this normal? Or is my car gone LOCO

[v-dubed]

do u have underdrive pullys???

[jesse]

no, since i don't even know what your talking about. are you even speaking english?

[v-dubed]

lol... no they shouldent be doin that then

[styleandspeed]

My 03 turbo S does it too. It is probably just your cooling fans or your AC compressor kicking on.

[hygieneboy]

Mine does this too. Many Beetles do this. It's not really "Normal" but you are not alone.

[VDUBYA]

Mine does it too. Always has since new. I drove the Service
people crazy when it was under warranty. I kept telling them
that it shouldn't do that but never got anywhere with them.
From what I've seen from folks posting here, this is not a
rare occurance. Just another "personality trait".

You want wierd? I have a Valentine 1 radar detector that is
powered by one of the accessory plugs (used to be cigarrette
lighter). When you first turn the detector on, it goes
through it's initialization sequence making all sorts of
noises. Well every once in a while it will make
the "startup" sounds while the car is running as though
it had been turned off and then on. There has to be some
sort of Gremlin lurking in there. Just not a serious one
I guess.......

[jesse]

Originally Posted by styleandspeed

My 03 turbo S does it too. It is probably just your cooling fans or your AC compressor kicking on.

I almost never use my AC and it still does it

[Slug]

Mine will do it usually around the first 5 mins. of driving at night, never after that. The dash lights haven't dimmed with it so it has never worried me.

Mine is a 2001 1.8t Sport, it has always done it and I have 72k miles on it. Its just one of those built in problems thats not a problem.

Wouldn't worry about it.

[noR]

you still have cooling fans that turn on and off at irregular intervals.

I notice the dimming occur usually when I drop out of cruise control to take my exit on my way home from work

[NJ Turbo]

Your Valentine 1 is just going through the startup because the power connection got unplugged for a split second.
My rader detector does that sometimes, it's because the plugs that go into the lighter sockets don't make great contact sometimes and they are spring loaded. So the vibration of driving makes it lose contact sometimes.
No gremlins there, just simple design weakness.

[John Koch]

VW uses a battery that's hardly large enough to power some of the electrical components in normal temps let alone all the cold weather package components in very cold temps. When replacing your battery, and replacing your battery will eliminate all of this,( I never notice it at all anymore)replace the stock one with the battery thats used in the Diesel model. It has way more cold cranking amps and way more reserve power. It can adequately supply power with only a small infrequent charge by the alternator. It does not cause the massive 14.6 + volt charge every 2 minutes that cause the headlights to dim and the fan motor to slow down. I was in Montana and it was -35 degrees F. I unlocked my car with the remote and turned the key to on and let the fuel pump get the fuel rail up to pressure. 5 seconds or less. I then cranked the engine about 4 turns only and it started right up. The speed of the starter was much faster even in this extremely cold weather. I know that the Mobil 1, OW40 European formula synthetic helped here too. I turned on my seat heat, the mirror heaters, the rear defrost and all the lights, high beam and fogs and drove off slowly. I turned the heater on at the very first sign of any warmth and had the fan on 3. I experienced no dimming or lack of a voltage supply. I highly recommend this upgrade. The Diesel's battery is only slightly larger in dimension but it does fit with some wiggeling and presistance. Of course the power steering reservoir must be un bolted from its mount and moved over to the left as far as possible just as in all battery replacements. No need to disconnect and remove from car. Now that Sears handles Optima batteries, we can all get the big boy battery for a very inexpensive install charge...This larger capacity battery stabilizes the entire cars electrical systems that includes the Engine management computer, bunches of sensors, actuators, switches and modules. It is a vey good up-grade for everyone, no matter what engine they have... JK

[jesse]

Originally Posted by John Koch

VW uses a battery that's hardly large enough to power some of the electrical components in normal temps let alone all the cold weather package components in very cold temps. When replacing your battery, and replacing your battery will eliminate all of this,( I never notice it at all anymore)replace the stock one with the battery thats used in the Diesel model. It has way more cold cranking amps and way more reserve power. It can adequately supply power with only a small infrequent charge by the alternator. It does not cause the massive 14.6 + volt charge every 2 minutes that cause the headlights to dim and the fan motor to slow down. I was in Montana and it was -35 degrees F. I unlocked my car with the remote and turned the key to on and let the fuel pump get the fuel rail up to pressure. 5 seconds or less. I then cranked the engine about 4 turns only and it started right up. The speed of the starter was much faster even in this extremely cold weather. I know that the Mobil 1, OW40 European formula synthetic helped here too. I turned on my seat heat, the mirror heaters, the rear defrost and all the lights, high beam and fogs and drove off slowly. I turned the heater on at the very first sign of any warmth and had the fan on 3. I experienced no dimming or lack of a voltage supply. I highly recommend this upgrade. The Diesel's battery is only slightly larger in dimension but it does fit with some wiggeling and presistance. Of course the power steering reservoir must be un bolted from its mount and moved over to the left as far as possible just as in all battery replacements. No need to disconnect and remove from car. Now that Sears handles Optima batteries, we can all get the big boy battery for a very inexpensive install charge...This larger capacity battery stabilizes the entire cars electrical systems that includes the Engine management computer, bunches of sensors, actuators, switches and modules. It is a vey good up-grade for everyone, no matter what engine they have... JK

THANK YOU!! May you live to be 1000 years!!