John Whyman Posted May 21, 2001 Share Posted May 21, 2001 I noticed this evening that I had a very faint steady glow on my ignition light when running. Usual bright and off when starting so alt is charging, and no dimming of lights anywhere. Is this the start of a sick alternator, or is it a normal 7 thing? Or do I have perhaps a dodgy earth or connection somewhere? any ideas. (Alt is a Bosch 45amp). Or perhaps i have taken leave of my senses in the glorious blatting weathercool.gif. Link to comment Share on other sites More sharing options...
Petrolhead Posted May 21, 2001 Share Posted May 21, 2001 Sounds silly but on odd occasions when it is realy sunny I have thouht my ignition light was glowing. I finally checked it in the garage. It was just the sun. If it still glows in the dark (no pun intended) it may well be a sigh that the alternator is on the way out. Does it glow all the time or just tickover - slipping fan belt maybe? Check with a voltmeter on the battery should be approx 13.5 - 14.5 volts. same when fully loaded ie lights, heater, heated screen etc on. Gook Luck Peter Better to go in a blaze of glory than to fade away teeth.gif Link to comment Share on other sites More sharing options...
tony pashley Posted May 21, 2001 Share Posted May 21, 2001 Terminals on the back of the alternator - or rather the large Lucar connectors that plug onto them. Mine seemed to be tight and well 'on', but when removed one was blackened and breaking down. Replacing connectors cured the problem. Worth a look anyway... Edited by - Tony Pashley on 21 May 2001 23:41:59 Link to comment Share on other sites More sharing options...
EFA Posted May 21, 2001 Share Posted May 21, 2001 The alternatopr light is powered by the voltage difference between your battery and a small descrete winding in the alternator. Its main purpose is to detect when the alternator belt snaps - i.e. Alternator output = 0v Battery output = 12v therefore difference is 12v - enough to brightly illuminate the ign lamp. Your battery voltage is 12v when not being charged by the alternator. The alternator output pulls up the battery voltage to 13.8v IF your batery is at 13.8v and the descrete wiring for the ign lamp is a little dirty or resistive in some way, then you get a small voltage (2 or 3 volts) which is enough to make the ign lamp come on dimly. Bottom line is to check all your connections are clean and tight. This will more than likely resolve the problem. Also remember the fault can be caused by a low desctrete output from the alternator, which has no effect whatsoever on the much heavier charging windings. Hope this explains/helps. Arnie Webb The Fat Bloke blush.gif in a Fast Temporarily Indisposed Vauxhall wink.gif See the R500 eater here See the Le Mans Trip Website here Link to comment Share on other sites More sharing options...
John Whyman Posted May 22, 2001 Author Share Posted May 22, 2001 Thanx all. I too thought it might be a spurious light like the sun, but this was at 10.oo pm last night, and even in deepest Somerset we don't see the light at that time, (unless blind drunk on Scrumpy).I did have a spade clip break on me some weeks back, but it is worth checking, and thanx Arnie for an explanation I can actually understand. Much appreciated. Happy motoring thumbsup.gif C7 WJW Link to comment Share on other sites More sharing options...
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