Ignition Problem

[Conger123]

Just fitted new alternator and battery but ignition light still glows slightly with engine running. The battery votage is 14.3 with the engine running. Any ideas

[hewhoisnotintheknow]

what do you mean by ingition light

[Conger123]

The red light sowing a battery. When the ignition is switched on the light should be bright red but go off when the engine is started, indicating the alternator is charging the battery.

[djheath]

What car is this on?

If you rev the engine does the light go off when the revs increase?

[jonathon]

bad earth. check between battery and car and body and engine

[Conger123]

The car is a Nissan Primera. I have earthed the alternator directly to the battery, no joy. The voltage across the battery and from the alternator power terminal are the same. 14.3 volts. The voltage from the alternator terminal which leads to the ignition light is around 12.5 volts, i.e 2 volts difference. The light does not go out on reving the engine. One would suspect the alternator but the effect was the same on the old alternator, which is why I bought a new alternator.

[hewhoisnotintheknow]

hmm, i would say duff battery, but youve changed that, check you earths

What voltage is on the battery when the car is turned off

[CHR15]

What happens to the Voltage across the battery terminals when the engine is running and you switch everything on (main beam, AC Fan blower, Screen heaters, radio etc)?

The voltage should stay the same if the alternator is good and the voltage regulator is doing its thing!

If the voltage drops like a stone, it would appear to point toward the Alternator (was it a new replacement?)

It is also worht checking all connections, battery, alt etc are clean and tight.