battery light on when headlights turned on

[justice4all3000]

my battery light comes on when headlights are turned on what should i do??

 

[accentstencil]

Get your battery and alternator checked by an auto electrician.

 

[m1lky]

With the car idling check the voltage across your bat. Should be at least 13v

 

[justice4all3000]

with the engine running and accesories running (headlights, AC, stereo ect) the batt is at about 14 volts however when i turn the rear demister on also it drops to about 12.3 volts is that ok?

 

[TonyJZX]

i would say no

should be 13.8 no matter what is going on

short? leak? in the rear demister circuit?

 

[justice4all3000]

i would say no

should be 13.8 no matter what is going on

short? leak? in the rear demister circuit?

How do I test the rear demister for problems?

Thanks

 

[m1lky]

Unplug it off the window. Probably under the pillar cover. Pull the fuse. Test for continuity on the car side of the connector not the window side (you shouldn't have it)

 

[justice4all3000]

Unplug it off the window. Probably under the pillar cover. Pull the fuse. Test for continuity on the car side of the connector not the window side (you shouldn't have it)

thanx will give it a try

 

[BlackVXGTS]

Replace your voltage regulator. Easy and cheap fix. The bushes in the regulator wear down over time and result in the alternator not being able to keep up its normal charge rate. Vary your test by leaving the headlights off and the rear demister on and see if the battery light comes on. If it doesn't then turn the headlights (I assume you had high beam on) to see if the battery light comes on. That should establish if the problem is the rear demister or the regulator (or some other part of the alternator).

 

[justice4all3000]

yesterday the battery light came on again, this time the rear demister was not on so i doubt its the cause of the problem. Where can i get a voltage regulator from? do i have to remove the alternator to replace it? (series 1 v8)