I have developed a battery light on my dash this morning.

It is showing full charge in the battery at the moment, but the light appeared on my drive to work.

It was not there in idle, but appeared when I started driving normally. If I rev the engine, the light goes away temporarily.

Is this a battery issue, or an alternator issue?

Actually, now that I've driven it a bit, the charge is showing just below half..

 

battery light is on - disappears when I gun the engine...

Is this the battery, or the alternator that's at fault?

 

Alternator 100% on its way out.

The battery light is actually not for the battery. Its shows lower than expected voltage is present, indicating low or no charge from alternator.

The battery will maintain voltage for a short while, that's why the voltage guage didn't drop much if any.

 

Threads merged, one thread per subject please

 

thank you.

How hard is it to change? Looks like a belt tensioner to release, a few bolts, and not much else...but it's -3 already, and I don't have a garage...

Andrew

 

Yah there's a little brace that runs across the bottom, but its very straight forward on the top of the engine

 

Just swapped it out - not bad at all...had to take off the antifreeze hose, so it was a bit messy - but not bad otherwise!