1G Battery drain narrowed down to alternator...

[91 TSi GP]

Ok I've been battling battery draws for a while now. I hooked up a test light (non led) between the negative terminal of battery and the cable. Fully lit up the light. Ended up pulling the main 80 amp alternator fuse and waalahh the light went out.

So I felt fright and rewired the alternator from battery to the fuse then to the post on the alternator with some heavy duty amp power wire. And yet again the light lit up. I took a my alternator out now thinking it was internally drawing power. Sure enough it failed and was under warranty. I got a new alternator in today and the fanned light is still lighting up.

I can connect the wire to the stud on the alternator and run only that wire to the battery. No other wire are connected to the alternator or the battery and the test light is still lit up. Could someone please toss some insight?

 

[nuclearr]

The alt fuse controls alot of systems not just the alt. You need to start your draw test over and get a digital multimeter and measure the amps start with the fuses. I have to do the same thing on saturday but I blew my mulitmeter the last time I did a draw test make sure you only hold it on the terminal for no more than 20 seconds.

 

[91 TSi GP]

How does it control more than the alternator when the alternator wire is the only wire running through it?

 

[nuclearr]

I am not sure how or why but when I blew mine the car quit running. Even though I still had enough battery to run the car it would spit and sputter. Some systems went haywire. My running lights came on all the time. Head lights would not switch off. Power windows would not work, door locks would, and much more. Granted this is on a 2g but as I recall my 1gs did similar things.

 

[luv2rallye]

Hint: You won't be the first to receive a 2nd and 3rd bad alt from an auto parts store...search these forums and find out how many dozens of times this has happened! Auto stores are famous for this, some chains way more than others.

 

[91 TSi GP]

For visual purposes this is how I am testing it... And the Alternator wire is the ONLY wire connected to the battery I unhooked everything else.

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[knochgoon24]

Try tracking it down this way.

Pull a fuse, place your test leads in where the fuse went. Test. Replace fuse. Remove next fuse. Test next circuit. Rinse and repeat.

 

[Infamous33]

If you think it is the alternator, remove the red wire at the back of the alt. (with the battery disconnected) tape it off so it won't short out. and then do the draw test. You should pull the connector at the alt also, it is powered off that fuse as well.
Someone mentioned this is a 2g ? your bio says it is a 91 tsi....
If it is infact a 91, than it looks like that fuse runs some other stuff....
According to the schematic, after the alt. fuse, the wire splices to:
Rear defroster
Condensor fan
A/C clutch
Auto seat belts
Headlight motors
Power windows
And power to the interior fuse box.
The tester between the neg post and the cable is right. You should loosen the cable terminal, connect the tester BEFORE you separate the cable from the battery because components will be powered up thru the tester.
Once you have the tester in the circuit, try pulling one fuse at a time.
Disconnect the door switches so you can have the doors open and reach the interior fuse box.
+1 to using a DVOM (Digital Volt & Ohm Meter) as it will quantify the size of the draw. Most DVOM only have a 10A main fuse tho, so you have to use care when testing.
That is the end of my electrical draw lesson. They can be a bear to find and you have to be patient !!

 

[91 TSi GP]

Ok in the freezing pouring down rain I was pulling fuses. When I pulled the 40amp alternator BAT. Fuse the light was gone. It has one wire white with a red stripe on it and goes into the harness that leads over to the alternator area. Is this the single power wire that feeds all the goodies over there such as headlights etc?

Edit: this wire probably feed the whole inside of the car as well with power right? So I'm not even close to finding it yet?

 

[luv2rallye]

Is this on the 91 or which car?

With the alt completely disconnected AT THE ALT (large wire on stud off plus connector plug of other wires to alt off) and that 40A fuse in place, is the test light on? If so, leave the 40A in place but start removing all other fuses both in engine fusebox and inside fusebox until light goes out.

Note: Previously when you used the 80A fuse, know that that fuse is also connected to many other things besides the alt. So connecting a separate wire from it to the alt proved nothing (to eliminate the alt as the drain source you would have had to run a wire from the battery + straight and only to the alt with nothing else on battery + or the alt).

 

[91 TSi GP]

Ok I was way off with the alternator suspicion ... it is something associated with the "room" fuse

 

[Infamous33]

What is the fuse number? I don't have my car here and I can't look up the circuits that are tied into that fuse without it. It is in the fuse box under the dash, right? Follow up and I will see what I can come up with

 

[91 TSi GP]

Yes under the dash... its in the very bottom right corner..

 

[Infamous33]

It would appear that is fuse #19, a 10 amp fuse. Here is the list of what is powered by it.

Dome light
Luggage compartment light
Foot light
Radio
MPI control unit
TCU
ignition key illumination light
Door lock control unit

Let's start simple, any lights on in the car? **I'm wondering if the trunk light switch got flipped on accidentally. The cargo cover does a good job of hiding it from view.**
Factory radio?
Do the door locks work the way they should?

If you don't find any lights on, the radio is easy enough to unplug. If that doesn't fix it, the door lock module is in the passenger's kick panel I believe.
I will stop there for now, lemme know and I will get deeper into it if you need.
Remember, acceptable draw is somewhere around 30mA ( that's milli amps) or about what the radio memory and security system draw.

 

[91 TSi GP]

^^ You're Awesome! ^^ As soon as I get home from work I will start checking all this. And the door locks are a bi*** sometimes..