ignition / battery light fault

[DamianS3]

When starting the other day my ign / batt light flickered out. Car starts OK buy pretty sure battery not charging. Volt meter low and getting lower. Makes sense as I know the light current draw helps start the alternator charging.

Given the dash was out a few months ago I am going to investigate bulb end first. Will I be able to get at it without removing the dash?

Thoughts / advice appreciated..

Cheers Damian S3

[steve j]

Hello Damian, I too had similar problems a few years ago, I replaced the brushes on the alternator and it cured my voltage issues, good luck.

[DamianS3]

Yea good point I had pretty much dismissed the alternator as it's fairly new but will get multimeter on it before I go up the dash may just not be kicking in though can I fool it somehow?

[Deeman]

Mine developed a problem started by a rusty earthing strap (the bit through boot and wheelarch where you can't see it and shrouded in plastic). Then when trying to jump start, it killed the alternator diodes ended up being costly, as by then I'd replaced the battery, earthing strap and a new alternator!! No problems since

[junglieD]

On my S2 I have experienced a similar fault. The issue turned out to be a poor connection to the bulb. With the charging system working correctly, the light extinguishes and voltmeter indicates positive as the RPM reaches about 1200 following a blip of the throttle.

When the bulb was not in the circuit properly, the charging would still initiate but at a much higher RPM such as 2500. I understand (from information on this forum) that such high revs can be enough to self-excite the alternator and commence the positive charge to the battery.

- maybe it's worth you trying to rev the engine (once warm) to a much higher rev range than usual to see if your alternator self-excites and indicates a positive charge on the voltmeter? This would then prove the serviceability of the alternator?

David

[shoab]

Hi

Have a look at this document for how to test electrical systems in a logical way. It is ver useful and could save u some time and expense.

http://www.atcc.org.nz/tcc/LucasFault.pdf

Regards

Graham

[TVR-Stu]

shoab said:

Hi

Have a look at this document for how to test electrical systems in a logical way. It is ver useful and could save u some time and expense.

http://www.atcc.org.nz/tcc/LucasFault.pdf

Regards

Graham

Graham, it seems to be a dead link unfortunately
Suspect it would have been a useful document to have a copy of too!

[RayTVR]

Try here

clicky

[TVR-Stu]

RayTVR said:

Try here

clicky

Thanks Ray, now got it!

[DamianS3]

Many thanks everyone will report back after I get in there