Battery Light

[erbs 42 1 Cars]

strange one i have here, when the lights are all on the battery light does not come on, but when i turn them off and have the blower going, the light dimly comes on.

 

Surely the lights draw more power than a fan?

[Anthony 1,003]

It's not uncommon to have the battery/charge light on very dimly when the heater blower is on full blast.

 

I know that there's not a single cause (Jackherer from memory had this happen when the main alternator power feed wiring was on its last legs for example - well worth double checking due to the fire risk if that unfused connection fails!) but I think in atleast some cases it's something more related to earthing or voltage drop on the interior power feed, as usually on cars I've had that have done this, the battery/charge light has blinked fractionally brighter in turn with the indicators - and clearly they consume next to no power!

 

If you put a multimeter across the battery terminals, when the light is dim you'll almost certainly find the alternator is still charging fine.

[u47sb2 27 2 Cars]

This happens on my rally car. Everything checks out fine with the multimeter. I wouldn't notice it if I hadn't removed the rheostat/dimmer for the backlit dials.

[Greggbladen 0]

My 205 rally car does the same but all tests fine I have fitted new alt and all new wiring but still doing it