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MG MGF Technical - Battery light stays on when engine is running.

My wife has owned a Eunos Roadster for a number of
years and only lets me drive it when she is in
attendance (her pride and joy). She is a member of the
local MX5 club and I am a member of the local MG Club
as we have mutual friends who own a mixture of the
said vehicles.

I had the opportunity to purchase and took it to buy
an MGF 2001 bog standard model in mint condition,
engine sounds great and goes well, however I had
problems starting her and decided that as the battery
was 4 years old, I would replace it and duly did so.

Installed said battery, no problems starting the engine but the battery warning light stays on. Any ideas on how I could cure this problem without trundlilng down to the MG dealer. I will also see
if some of my MGF friends can throw any light on the
subject, but all views are welcome

bill pearson

Was the battry warning light on before changing the battery as well. If so, the generator??? may be faulty.

Johan Slagter

Thanks for your comments.Bought this car at auction
and it sounded ok. Staff had to jump start it so
I could leave the premises. I ran the car along a
local dual carriageway for some miles and time in
order to charge up the battery and felt that I had
not bought a "dud", all was running sweetly and no
horrible warning lights came on or stayed on. Yet
when I came to a stop and turned off the engine, I
could not restart it, not even a click, without
using jump leads. Again once it was going, it was
ok, but as soon as I put on the headlights, the engine
cut out, so hence I put in a new battery and now the
battery warning light stays on!

bill pearson

Sounds like the engine has been running on the battery itself. Could you check the charging of the battery with a voltmeter.

it could also be a bad contact at the batterycables or something like that.

Johan Slagter

Check the connections on the alternator. You will have to remove the cover under the rear parcel shelf. Check that the connections are OK on the alternator. Don't put a spanner on the the main big cable connector until you have disconnected the battery.

I had the main cable fray at the alternator and the battery slowly went flat over a period of time. NO warning lights etc.

If this isn't the problem then it could be your alternator itself.


Bruce Caldwell

Hi! Johan & Bruce,

Many thanks for your advice and commonts. I have
booked the car into the Phoenix MG dealers in
Northampton for their mechanics to have a look at
the problem. 69 per hour for the first hour "thank you very much", but tomorrow (Sunday) and I will
remove the cover under the parcel shelf and shall
fiddle around (battery disconnected of course) in
the hope that I can save myself some money.

Will let you know the result, one way or another.

Regards Bill
bill pearson

Dont forget your radio code before you whip the battery lead off !

Adrian Clifford

1. Faulty alternator
2. cable from the starter motor to the alternator (fixed
by a screw has come loose.

2. was the problem I had.

To everyone who tried to help!

Had to give up on Sunday, could not find the fault
and had to take it to the MG dealership, who surprise,
surprise, found it was a faulty alternator. 300
later I have got a very nice car that runs very well
and the battery light does not come on when the
engine is running.

They also told me I need two new rear tyres at 125
each (get lost) and that the front discs and pads are
badly warn which they will do for about 250 (get lost). One of my MG contacts can obtain the
ventilate discs and pads and will do it for 125 all
in. Tyres, well I suppose I better ring National,
Kwit-Fit and other locals to see what deals they are

Thanks for your support. Its good to know this site

Regards - Bill
bill pearson


Before spending money on tyres, look into the archive and recent threads. Some tyres have caused F/TFs to become quite twitchy for up to 500 miles of running in.

The new TOYO TS-1S & R range have got a very good reputation in a short space of time (I've used them on a previous F and they will go on the TF sometime during 2005).

Bridgestone also get good reports.

Goodyear F1 were considered the 'bees knees' for the F until GY changed the compound and caused some problems.

Thank goodness the NCT3 has been dropped and the NCT5 is not considered a suitable alternative.

So far, my TF has been very dependable on the OEM CONTIs.

This thread was discussed between 04/02/2005 and 08/02/2005

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