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MG TF 1.8 2002 - Battery light fault #

Posted by Liam Hall on February 10, 2011, 7:53 pm

Year of Manufacture *: 2002 '52
( Optional ) Engine Code or CC: 1.8

Ok, hoping someone can help.......
MG has been in to me for an alternator problem, not charging.
Did the normal and checked voltage, nothing fom alt.
Fitted a new alt and still no charge.
Have battery voltage at the alt, so its not the 80A fuse.
BUT - I have no battery warning light on the dash.
Have checked the fuses, have had the dash out, bulb is fine.
Really not funny now, taking me far too long!
Have I missed anything obvious?

Re: MG TF battery light fault

Posted by andyhyoung <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT5148' width='330' height='300' border=0 style='border:none;'> on February 10, 2011, 8:42 pm, in reply to "MG TF battery light fault"
Andrew Young

This is luckily only a basic charging system on these.You need to test the warning light circuit from the dash pod to the alternator.The charge w/light earth circuit to alt is via a thin brown/yellow wire that exits the pod.Just above the fuse box is a multipin connector block where you should find this wire.With ign on ,use a test probe to ground the light.If it lghts then the dash circuit is ok.Do the same at alt end,ground brown/yellow to test w/l circuit.If no light,then you have an open circuit somewhere to engine bay.The wiring diag shows this circuit goes thro the fuse box,but is only an in and out.hth

Re: MG TF battery light fault

Posted by Liam Hall <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3033' width='330' height='300' border=0 style='border:none;'> on February 14, 2011, 4:49 pm, in reply to "Re: MG TF battery light fault"
Liam Hall

Thanks for your reply, I have done what you instructed, and it lights up the bulb, both when tested at the clocks and alt end.
But plugged into the alt, no light?!!!!
Cant decide what the other wire does, it is red with a white trace (or vice cersa, hard to see down there)

I am pulling my hair out now.
Any help greatly appreciated.

Liam

Re: MG TF battery light fault

Posted by Paul Howd on February 14, 2011, 8:52 pm, in reply to "Re: MG TF battery light fault"
Message modified by board administrator February 15, 2011, 2:39 pm

what make is the replacement alternator? It sounds like you might have a dud.

(Even without an external supply via the warning light I have found that "Traditional" alternators will useually still come on charge if you give the engine a good hard rev.)

Re: MG TF battery light fault

Posted by martin simonsohn <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3223' width='330' height='300' border=0 style='border:none;'> on February 15, 2011, 10:24 pm, in reply to "Re: MG TF battery light fault"
Martin Simonsohn

hi just looked at my diagram for the tf and it shows 12v positive brown and brown and yellow warning lamp circuit normally labeled as DF
are you getting the warning lamp when you turn ignition on if also does the alternator have a plug connection or are they connected with eye terminal if with eye terminal have you connected to the correct terminal and not to the winding take off also check the earth to the alternator.
note the tf diagram shows no red with white tracer or white with red trace
normally on rover white with red trace is a starter wire
hope this helps martin

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