Ignition warning light - New alternator.

[pete east]

Having fitted the new Valeo alternator, mentioned in my previous post, I had time to complete the check of its installation today, and all seemed OK. I turned on the ignition,but got no red ignition light at all. I checked everything else including lights, indicators, hazard flashers, heater fan etc, and all works fine including the indicators for main beam, and trafficators, but no red light for the ignition. I checked the ignition light bulb, and that is OK, so had a go at starting the engine to see if that would `wake up' the ignition light/ circuit. Engine started fine, and idled without a problem, and all the instruments came to life ok too. The alternator has the normal 3 spade terminal (one small - two large) plug in socket which I took out, checked, and plugged back into the new alternator several times. So at present I have no way of knowing if the new alternator is doing what it is supposed to do, nor why the ignition light does not come on at all. Didnt want to chance going any distance, in case the car was only running on the battery, consequently wondered if anyone out there has had a similar experience, (where everything seems to be running fine except the ignition warning light) and could offer any advice on how to try to sort it out? As allways any advice would be much appreciated.

 

 

[shn7]

Get a multimeter and check the voltage across the battery terminals with engine off and then running. Expect 12.5 off and 14.2ish running. If there's no increase running then clearly not charging.

 

If you haven't got a meter then I'd suggest buying one as they are often useful and a cheapo digital one can be bought for less than a tenner.

 

Steve.

Not forgetting Percy the Polar Bear who recommends

Puddle Pet Care

[Mick Day]

Also turn the ignition on (do not start engine) & check you have 12 volts on one side of the red ignition light. Do the same on the other terminal. If 12 volts on both then there could be a problem with the alternator/wiring or both.

[pete east]

I will try the multimeter to check that the ignition light wiring is OK,might also try disconnecting the alternator plug, and see if the ignition light comes on when the ignition is turned on (but wont start the engine with the plug out) just to see if I get any sign of life from the ignition light. will also check the (small) spade terminal, to make sure it is engaging in the (small) spade socket in the plug socket. other than checking the voltage across the battery terminals, with the engine stopped and then running, not sure how to find out why the ignition light does not come on at all? or if the alternator is in fact charging?

[NevDyson]

Pete,

 

Check the wire from the alternator to the lamp. Disconnect both ends do a continuity cjheck on the wire, it will at least tell you if you have a damaged / broken cable between dash and altenator.

 

Check as others have said that you have a feed to the lamp with the ignition on. The live feed goes to the alternator and the lamp illuminates as it can get to earth / negative when the alternator is not spinning, when the alternator is spinning it will not allow the feed to go to earth / negtive. You can also just put an earth from the alternator side of the lamp to earth / negative to ensure you are getting a feed to the lamp.