Ignition Light stays on

[Karl]

Hi

When I start me RV8, although the brightness dims considerably, my ignition light does not go completely out.

Circuit is from Alternator to lamp to Switched Live.

Have I got it wired wrong or does this mean my alternator (which I've spent hours bringing to a mirror like finish) is shagged?

Karl

[Bernie]

Or your battery perhaps could have a shorted cell. Whatever - what you need is a meter, and check that the battery has 12v or so across it with ignition off, and that the alternator gives out 14v-ish. Vince is the real electrical man, but he doesn't tend to trespass here much these days...

[Karl]

Thanks Bernie.

I've done that and all is as it should be (battery reads just under 12v, alternator give out around 13.5)

I feel I might be worrying unecessarily as the car is currently up on ramps in the garage so I can't run the engine for long without a gas mask.

I suspect if I charge up the battery from the mains and give it another go I might get the thing to go out completely.

Cheers

Karl

[Happy Jim]

Karl,

"What does that little red light that says ALT mean when it comes on?" Very basically, it means that either the alternator output voltage is lower than the battery voltage, or the battery voltage is lower than the alternator output voltage. If the light gets dimmer as you rev up the engine, then you most likely have a problem with the alternator. If it gets brighter, then the battery is most likely bad."

Stolen from a very good explanation at the following URL

http://www.vtr.org/maintain/alternator-overview.html

Cheers

Jim

[Karl]

Woeful thanks Jim . . . . . has anybody got a spare alternator?

On a more optimistic note though, it is probably because the voltage regulator (internal to the alternator) is malfunctioning. As I said previously, the voltage output of the alternator is in excess of 13, therefore above that of the battery. At least this should allow me to continue testing bits.

As a matter of interest, does Lucas (or anybody else) still make an alternator that is a direct replacement for the 3.5 Rover?
:}

[Bernie]

Rimmers do everything - £121.55 for an alternator. See -

http://www.rimmerbros.co.uk/cgi-bin/...0Major%20Units

Personally I went to the local scrapyard and picked a grim looking specimen from the shelf, paid £10, cleaned it up, works fine.