Thread: Battery Light Coming on

Alternator on its last legs,
Don’t get stranded, get onto it.
If tackling yourself you will need a big thin Spanner for the belt. I think possibly only a custom one will do.

Originally Posted by surfingooner

Driving last night, and my battery light came on.

Started today and was fine driving to work, no light came on. ..................... , Matt.

The light comes on to tell you that you're pulling more out of the battery than the alternator can replace. At night you have the lights on which put more load on the alternator, generally not so during the day. The actual fault may be worn brushes which are easily replaced along with the regulator, worn slip rings or a crook diode. All individually fixable but realistically its probably time for a replacement or rebuilt alternator, especially if it looks original. Petrol or diesel ? the diesel alternator is more complicated/expensive than the petrol as it has a vacuum pump associated with it. Avoid the 'el cheapos' as they're just not worth it in the end.

Deano )

Originally Posted by DeanoH

The light comes on to tell you that you're pulling more out of the battery than the alternator can replace. At night you have the lights on which put more load on the alternator, generally not so during the day. The actual fault may be worn brushes which are easily replaced along with the regulator, worn slip rings or a crook diode. All individually fixable but realistically its probably time for a replacement or rebuilt alternator, especially if it looks original. Petrol or diesel ? the diesel alternator is more complicated/expensive than the petrol as it has a vacuum pump associated with it. Avoid the 'el cheapos' as they're just not worth it in the end.

Deano )

Thanks Deano, it is TD5, I also got a nanocom recently and when running it was drawing 14 volts, but haven't had in for about a week as had some software problems which got sorted today so should find our more on way home tonight. I only had the side-lights on at the time when it came on last night, looks like an expensive item from research today, I see a new project brewing.....

Cheers, Matt.

If the big round plastic cover on the front of the camshaft is leaking, it can foul the brushes in the alternator with oil.
The alternator is common with many Toyotas so parts are readily available.
Mine went at about 134K and seeing I needed the car back on the road immediately I bought a new one, but later I pulled the old one apart and found the only thing wrong was that the brushes were filled with goo. AFAIR the brush holder with brushes is only about $50 and available on ebay or probably from any auto electrician.
I have fixed and kept the old one as a spare , but it hasn't been needed.
They seem very reliable.
Regards Philip A

Thanks Gents, nanocom now working and upside down as desired ! No light on on way home, 14 volts showing on screen. Stop for diesel and comes on when re-start and now showing as 11.75 to 11.95. Get home and re-start again and back to 14 and no light on, and I should add no car lights on at all throughout this.

First question is to confirm this is showing what the alternator is producing?

it seems to be working perfectly and then not, would this be usual, and can I use the nanocom to check further ?

Thanks for any help, Matt.

Yes the nanacom is showing what you dont want to see.
And yes your alt is toast unless your handy enough on the tools to diagnose and fix it your self

See this page and the link halfway down with a PDF tutorial on how to rebuild your alternator.

Td5 alternator

Just start with the bit up to replacing your brushes (and regulator also if you wish) and also clean the slip rings. 95% of the time its just the brushes need replacing and the whole thing cleaned of oil.

Parts available on eBay e.g. here: DEFENDER & DISCOVERY 2.5 DIESEL TD5 1998 - 2006 ALTERNATOR REGULATOR & BRUSHBOX | eBay

This seller sends instructions as well. Mine is original at 305kM with just brushes change and a clean only, about 15,000km ago.

Many thanks Simon,

I will do a little more research on where to get the bits from as delivery looks to take too long here (not sure if my alternator will last till January), but I am going to follow your advice and hope it does the trick.

Fingers crossed, and will report back when job done or if anything changes in the coming days / weeks.

Cheers,

Matt.