2G No battery light/low voltage

[Matthew Lipford]

So my car died the other day and I found some loose wires to the pigtail 4 pin harness that plugs into the alternator. I have checked the 100 amp fuse many times and have battery voltage across it. If my battery light is not coming on at all can this still be a bad alternator? I have fixed all the wires on the pigtail and the output voltage running is from 2-10 volts on the alternator. So for some reason, maybe voltage regulator or ecu? Will a bad alternator cause the battery light to stay off ? Thanks

 

[Vegas Smith]

Perhaps, the battery might be completely dead because of it. Have to tried jumping the car yet?

 

[Matthew Lipford]

Yes, I can jump the car and starts fine. If i charge the battery it will drive for a good hundred miles but I will notice that my voltages will start dropping and eventually will die. I checked the voltage at the alternator and it's changing from 2-10 volts. I took the alternator to autozone and they said it's bad. Shouldnt my battery light be coming on though? I don't want to buy another alternator and fry it because of some other problem.

 

[DogWhistle]

Weird factoid about DSMs: The battery charging circuit is not complete if the dash indicator bulb is burned out or missing. Make sure whatever event happened didn't blow your dash bulb.

 

[Vegas Smith]

Alternators have always been a problem with these cars due to the high heat from o2 housing and the power steering above it. It's probably just a bad alternator that won't charge the battery; hence the battery only lasting 100 miles or so. I'm not sure about the battery light though.

 

[miguelmcv]

Does your battery light comes ON when turning the switch to the on position?, if it doesn't then you have a bad bulb.

If the alternator tested bad then it's bad no questions asked, now the wire that was loose at the alternator plug needs to be fix in order to have all Working properly.

Replace the alternator and go from there, let us know how it does.

 

[miguelmcv]

Remember the power steering fluid will kill the alternator in minutes, so make sure you have leak free otherwise you will have to change it again soon.

 

[Matthew Lipford]

No the light doesn't come on when I turn the key forward. I'm working on getting another alternator and let you guys know what happens. Thanks for the input.

 

[miguelmcv]

If it's not on when turning the switch to the on position then your bulb is bad or it's not getting power to the light,.

 

[Matthew Lipford]

Yes I realize that but I was curious if the bulb is getting voltage from the alternator ? Can a bad alternator cause the bulb to not work ?

 

[miguelmcv]

No, it's backwards, a bad alternator or a brocken wire will make the light to stay on.

 

[Matthew Lipford]

ok thanks Miguel

 

[Detective Coating]

Either your bulb is bad or the generator relay is destroyed, those are the only 2 things keeping the light from working.

 

[Matthew Lipford]

Where is this generator relay? after doing some searching I thought the 1g was the only ones with the relay. Anyone have a picture ? What wires I can trace to it? Thanks

 

[Vegas Smith]

I'm not sure where it is but here are the service manuals, and I'm sure you could find it in there:

http://www.dsmtuners.com/threads/download-a-2g-service-manual.324090/

 

[miguelmcv]

Is under the MAF right aside the radiator reservoir

 

[miguelmcv]

http://www.dsmtuners.com/threads/omron-relay-is-it-broke.402040/

 

[Matthew Lipford]

So I found where the relay used to be and its missing. I have voltage on one wire. Appears to have been missing for awhile.

 

[Matthew Lipford]

Just tried swapping bulbs and the bulb is not getting power. Bulb is good. Next step anyone ?

 

[miguelmcv]

That's not it, that looks like the boost control, the other one is right on a side is attached to the same bracket. It should be a 4 wire plug (relay style)

 

[miguelmcv]

Check this first 2 pics, that's what you will be looking for, just google

DSM 2g ALTERNATOR RELAY and click on images

Quick question what year is your car keep in mind 1999 didnt came with alternator relay though.

 

[Matthew Lipford]

Ok so I found this and put new connectors on it but nothing.. Thanks

 

[miguelmcv]

Your next step is to check the bulb at the cluster.

 

[Matthew Lipford]

I checked it earlier and it's good.

 

[Matthew Lipford]

I have a 95 tsi.