battery/ ignition light staying on once ignition off.

[GraceAnais]

when i switch the engine off my car (1996 Ford Fiesta 1.3) the battery/ ignition light stays on. even when the keys are out completely. whilst i am driving it is not on ( which other people have said means it is NOT the alternator - [sp?]) - i think it is some kind of electrical fault as other things haven't been working either - such as the alarm when the lights are left on etc. i have bought a new battery for the car but because the light is staying on it just keeps draining the battery. i'm booking it in the garage but just wondered if u guys had any idea what may be wrong with it. many thanks - grace

[Jay70]

Hi Grace,

This happened on my wifes 1994 Escort and it really baffled me because when an altenator normally goes the battery light comes on when the engine is running which indicates a low voltage output because part of the rectifier circuit normally goes open circuit and only half wave rctifies. But there was a short in the (rectifier) output stage of the altenator which was drawing current when the ignition was switched off which also caused the battery light to remain on even with the key out. it was dragging the battery votage right down too. I was lucky enough to have a good spare battery which i connected and the same thing happened. I was beginning to suspect a real major electrical fault because i have not seen an altenartor do this before but I replaced the alternator and it solved the problem. It wasn't a difficult job and it took me about an hour to do. If you take in your old unit to a motor factor or ford you can trade the old one in for a reconditioned unit - mine was about �55 with 12 months warranty. It sounds like the same fault to me and most people told me it wasn't the alternator - even a garage employee. I wish you luck and it would be nice to know how you get on.

Jason

[GraceAnais]

Thanks jason - that sounds really helpful. i think i'll advise the garage of this when i take it in as i think they were quite baffled by it when i explained what was happeneing to the ignition light (cue mechanics distant , puzzled face which ensures customer that their bill to fix said car will probably equal the debt of a small country!)

i've already started searching the autotrader for a new car as i can see this being a big problem! hopefully with a new alternator it may sort itself out. the problem with electrical faults is they are often trial and error and one can spend an awful lot of money in a an effort to determine the problem - often with the problem still not being solved. Thanks ever so much for your help - i'll let u know the outcome. many thanks Grace.

[Jay70]

Just another thought Grace,

If you have got AA homestart cover or similar call them out and explain the what you suspect. They are normally very helpful and are good at diagnosing faults they can also fit a new alternator for you if it is that causing the problem. If you keep driving it and it is the alternator it wont be long before you have a flat battery and get stuck out somewhere like my wife did. If there is a short in the alternator then you will have a job to jump start the car too. I'm an electronics engineer by trade and thats how I detected the fault as I could detect the short circuit in the alternator. I can't garrantee that is the problem with your car but I'm about 90% sure it is as it sounds identical to what my wife's car did.

Best wishes Jason

[Jay70]

P.S. If it does turn out to be this then dont worry about having to replace the car as the new alternator will sort it and not other harm should have been done. My wifes car is running fine now and has been for a couple of years. Sometimes garages like to put fear into people and make them worry.

[nadja]

Thank you Grace for that helpful tip because im haveing that same problem. Thanks a lot.