So, i've got my 2002 Jetta for a little over a year now and the battery died on me this morning.

No big deal, i thought. Went to my local flaps and got a new one, replaced it, so far so good.

Then i went online and low and behold found out that my car seems to have a problem with the battery draining.


Now, here's the question:

My car came with the "neat" feature of headlights that are always on. As soon as i turn the key, they light up, no matter if night or day.

How can i turn my headlights off so i can actually recharge the battery while driving during the day?
Andy

Google
VAGCOM

Download that and buy a cable from Ebay.
There is alot of info on how to use it on vwvortex.com

And yet more at the real site:

Ross-Tech Website

It's not 'VAGCOM' any more due to a silly trademark squabble with Volkswagen AG (a major purchaser of the product, BTW...) it's now officially "VCDS."

New name, same product.

It's a few more $$ but I always suggest supporting Uwe and buying a real cable from Ross-Tech. (I worked there for a few years but that was 3 years ago; I don't get anything from the sales except knowing that people who buy the real deal have far fewer problems...)

If you -do- buy a 'clone' interface cable, at least register the software (used to be $99). Real Ross-Tech cables act as a license dongle and include a fully activated license key.

DLR coding is frequently found under 'Central Convenience.' But there will be a section on the Ross-Tech site called "Things I can do with my car" organised by year and model.

But if the car in question has sloppy handbrake cables like many, the "cheater" way to turn off the DLR is pull up the handbrake a click.

yep, thats what works on my jetta.

It is designed to run with the headlights on.
I would suspect a bad battery as my Jetta was hard on them in San Jose. But, all in all, it was winter in Denver that finally killed my second battery.

Not to hijack the thread, but...

Stupid Question: Would the VAGCOM (Ross-Tech) and cable be a must -have tool for a 00 Jetta 1.8T (just purchased used. runs great)? If the dang thing would work on a Subaru too, I'd be all-in!

some folks have pulled relay 173 out (DRL). Not sure if 173 is the DRL relay on 2002 models.

If you think it's a charging problem check the alternator cable. The crimped ends get corrosion inside causing high restistance. Also check the battery fuse box for bad connections and melting. Your car does not have a central electronics module like the later cars so the DRL's cannot be turned off using a scan tool.

The Ross-Tech site explains this in much greater detail than I can here, so I won't even try to duplicate it.

for VAG cars (loosely, in North America, VW & Audi) VCDS provides 'native mode' diagnostics for every diagnostic-capable Electronic Control Unit (ECU) on the car. For "many" vehicles, it also provides OBD-II diagnostic capability. I have used it with great success on my '97 and '04 Outbacks, and I found even the OBD-II data to be invaluable when performing the engine transplant in the '97 a couple of years ago.

It works on my Titan, too.

(Some American cars use a different ardware interface that is not compatible. So much for "standards." This is all on the Ross-Tech site.)

The real-time data acquisition of even the OBD-I channels and the ability to do trending and logging is extremely useful, IMO. I couldn't imagine trying to do service on a (diagnostic capable) VAG car.

The newer cars (I want to say MY 2005 and newer) use the CAN interface protocol and you will need a newer flavor of cable. Uwe went to USB because more and more smaller computers were coming without serial ports; they are now fairly rare. There is no performance advantage with UDB - the car speaks good ol' serial and so there are protocol conversions on both ends of the wire to make USB work.

Mhmmm. I get 14.5V across the terminals when the engine is running. It seems the alternator is good.

But i'll check it and the fuses anyways.
Andy

If the current being produced by the alternator is greater than the current being drawn by the system (including headlights), then the battery stays charged. If not, your car will stall out on the side of the road with battery voltage drops too far.

So, something is wrong if you're not getting a full charge on your battery. Corrosion, failing alternator, failing battery to name a few possibilities. DRL is not the problem. But if you don't like them, do the ebrake trick.

Put a load on the system. Turn on everything and let it idle for a while, then see what the voltage is. Also check to see if any of the charging system connections are getting hot, this would indicate high resistance.

After reading through this thread, I've noticed one GLARING error. Your alternator, as all automotive alternators, IS NOT a battery charger. It's a battery maintainer. You attempt to charge your battery by driving the car around for a while and you run a VERY REAL chance of toasting your alternator. Besides, you'd have to run around for about 24 hours, assuming the alternator lasts that long, to fully charge a discharged battery. A small battery charger costs about a third the price of your alternator, and you can use it on other cars ......................... DRLs don't put any real drain on a electrical system in good working order.

The Cap'n

as always the Cap'n is spot on; DRL's have been mandatory in Canada since 1990 and I never heard of it causing drained batteries. Sounds like something else was the cause.

Hope you figure it out Andy

bash em out....and throw it out
i will never own a late modle VW again
i had so many recurring electical charging problems with my corrado, and jetta
i decided to buy a jeep,
my opinions may be somewhat jaded
however i do still own a 79 rabbit...which i love dearly

I work on post 2000 (A4) J/G/NBs all the time, often 2 a day. I've sold 2 alternators in 9 years, a host of batteries at the 5-6 year age level, and other than that I've done almost no electrical work on these cars. Oh, lots of low beam bulbs, just like all the newer cars with DRLs, and several aftermarket radio installation repairs because of the Bozo installers at Circuit City and Best Buy who can't or won't read simple technical bulletins.

The Cap'n

I think I'd use a 5 iron.

Disconnect the low beam power cable, splice it into the horn cable. Charging circuit now has continuity. Horn draws less current then headlights.

But everyone gets mad at you at night, while you are honking continously to keep your lights on. :-)

Zach