Ignition Warning Light

[Media]

Well last week I finally had my four wheel alignment done ready for SVA in two weeks time. Before fitting the dreaded windscreen I am now in the process of doing a final check on the dashboard wiring, and have found that the warning light on the rev counter which I presume is the Ignition warning light, only lights up after engine startup, and after throttle is engaged.The wiring for this light comes from the D+ connector on the alternator. Should this light come on when the ignition is turned on, or is it there to show that the alternator is charging the battery. Should there be a light to inform you when ignition is first switched on.

Can I also say that I sympathies with those that have past the SVA or who like me are about to take the leap into the unknown, especially at the Llantrisant testing centre in South Wales.

Cheers :rolleyes:
Geraint

[Swamprat33]

Hi Geraint, Not too sure about the warning light, but I wish you the best of luck for your SVA.

2005 looks like a good year for completing cars, with at least 3 new cars expected with you, Chris and Mick (and hopefully Stuart as well).

have I missed any more?

cheers
Tim

[catswhiskers]

Well Geraint,
Whilst I have a separate warning light on the dash as opposed to being within an instrument, my understanding is that it should come on when the ignition is switched on, go out when the engine is running OK and only come on if the alternater stops charging due to drive belt failure or similar.
Best of luck in the SVA. Looks like you'll beat me by about a month or so. :)

Mick

[AndyH]

Hi Geraint,

Did you ever fix the light problem... I've got the same..

Regards

Andrew

[CorseChris]

The warning light should (normally) come on with ignition, then extinguish once the motor is running and the alternator has kicked in. If you are getting the opposite, then one side of the warning lamp is not going to the right place - one should go to ignition switched live. The other to the control terminal on the alternator.

[AndyH]

Hi Chris,

I'm wondering if my alternator has stopped working post transplant from Alfa.

With the engine running I was only reading battery voltage from the main terminal to earth.

I expected to see closer to 14V.

Andrew

[CorseChris]

Typically, the ignition warning light is used to provide the initial 'bootstrap' current for the alternator. What you see if the bulb has blown in a normally wired setup is that the alternator either won't kick in at all, or until the revs really pick up. From your description, the warning lamp isn't seeing 12V at switch on, or as you suspect, it could be faulty (is it a different unit or did you swap it over with the motor?). If all you have done is swap the motor, then a suspect alternator is a place to look.

Some simple checks;

Unplug the wire from the D+ terminal of the alternator, switch on the ignition then splash the wire to ground - you should the the ignition warning light come on. If you do, the alternator likely has a problem (could even be earthing - depending on how it's mounted, it might have ended up isolated from the block).

If you don't get the warning light coming on when you do this test, then somehow it's mis-wired. It should be simple enough to temporarily rig up a small bulb between igniton switched 12V and the D+ terminal then fire it up as a final proof. As you say, you'd expect to see nearer to 14V on the output of the alternator when all is working right.

HTH

[AndyH]

Thanks Chris,

I've swapped the alternator with the engine.. It was working, now it's not.

I'll try the test.... I'm picking up a new regulator and I'll try this next...

I've had to modify the adjustment clamp mount slightly to avoid fouling the anti-roll bar, so it's possible (even though I taped it up), that I may have got some aluminium into the alternator somehwere..

It's also not impossible that I've done some welding with alternator on the engine... I thought I'd avoided this, but you never know.

If the regulator doesn't fix, then I'll need to get it looked at.

Many Thanks

Andrew