car (battery) goes dead when headlights turn on/off

[AWDTireSmokeTsi]

I just installed my EGT and Oil Pressure gauge a week ago. Everything was fine until today, whenever I turn my headlights on/off, the car dies. If the car is rolling it will start back up right away but if its sitting, the battery will completely go dead. I checked my wiring for the gauges and everything is fine, (good connections, no wires touching, good ground etc). The only thing I can think of is a bad ground, SOMEWHERE. How do I go about finding a bad ground, if thats even the problem?

 

[chovis38]

That's what I would have told you to do- check for rubbing wires, bad ground, etc. It possible could be your alternator. Does the car die only when you turn your headlights on? What about when you have all of your accessories on at the same time? Do you have a volt meter? I would load test the alternator, and/or use an amp clamp to see how many amps the alternator is drawing.

 

[AWDTireSmokeTsi]

Ita only when I turn my headlights on and off, I even ran my A/C and it didnt die on me, so its something to do with the headlights.

 

[brokencpsd95tsi]

sounds like alternator or battery to me....test them with an OHM meter if ones available.

 

[AWDTireSmokeTsi]

If it would be the battery or altenator, then why does it only do it when I turn the headlights on OR off?

 

[brokencpsd95tsi]

most likely your alternator has weakened........check it with an ohm meter.
It may be able to keep up with MOST of your stuff but when you turn the headlights on it just can't take it anymore.

 

[brokencpsd95tsi]

I've had this kind of problem twice now....once it was a battery, once it was the alternator.

all I'm saying is just test those two things first....hell, it might be something else. Just sharing my experience.

 

[luv2rallye]

Headlights do draw a lot of power so it could be a bad alternator or battery. Does it die when you turn your blower fan on high (it draws a lot too)? But since it started after you installed a EGT and Oil Pressure gauge, why not temporarily disconnect them and see if problem goes away? It sounds like you may have a partial short draining the battery till where just the load of turning the headlights on does it in. Or the charging system isn't working (or battery is won't hold a charge) which amounts to the same thing.

 

[AWDTireSmokeTsi]

I unhooked my egt and oil gauge and it still does the same thing. Im gonna put in this Optima Redtop I have here and see what happens.

 

[luv2rallye]

Check the voltage on the battery when the car is running. It should be at least 14 volts or your charging system isn't working. If you suspect a power drain (short) somewhere, find it doing this: http://www.dsmtuners.com/forums/showthread.php?s=&threadid=54846