Ignition warning light - potential fix
Discussion
Hi
I have fixed my glowing ignition warning light on my Griffith 500 (staying on after starting the car), and just wanted to share my findings.
First I checked the alternator. Is was charging, no voltage drop on either sides, ac voltage test and checked all 9 diodes. Everything confirmed it was fine.
I read some post on PH about the symptom "ignition warning light stays on", but i never found or managed to understand what the underlying cause was (except for the obvious reason the light stays on - the alternator is not charging). So, I tested a little further.
I tested that the exciter wire going from the ignition switch to the alternator was not grounded prior to the alternator (the ignition warning light is part of this circuit). If it wound be grounded current could flow and the light would be on. No grounding.
I then tested if the alternator was delivering battery voltage to the exciter wire, once the car had been started and the alternator was charging. With ignition on but engine off 12v is delivered through the exciter wire to alternator. This makes the led light up and it delivers voltage to excite the alternator to start producing a charge once the engine is running.Once the engine starts, the alternator is self-exciting and generates 12v back through the exciter wire, which balance out the 12v coming form the ignition switch. And thereby the Led light goes out once the engine is started.
I did not find 12v coming from the alternator to the exciter wire. Also, the alternator stopped charging as soon as cut the connection between the alternator and the exciter wire. I found my problem.
The alternator regulator (a module within the alternator) sense the battery voltage and the load on the system in order to adjust how much the alternator should generate and it receives the initial 12v to excite the alternator to start charging. Once it has started to charge it is self-exciting, and it sends voltage to the exciter wire. This was not happening on mine.
So, despite having an alternator charging as it should. It was faulty.
I replaced just the alternator regulator, which sits on the back of the alternator under the plastic cover. It now self-excites, delivers 12v to the exciter wire with engine running and the ignition warning light goes out once the engine starts.
So, this might be the cause of the led glowing despite having a charging alternator. To test it I made a loop with a couple of wires with alligator clips on. I did not want to disconnect the exciter wire with the engine running and potentially cause a short. Hope this might be help if you have this symptom.
Cheers
Michael
I have fixed my glowing ignition warning light on my Griffith 500 (staying on after starting the car), and just wanted to share my findings.
First I checked the alternator. Is was charging, no voltage drop on either sides, ac voltage test and checked all 9 diodes. Everything confirmed it was fine.
I read some post on PH about the symptom "ignition warning light stays on", but i never found or managed to understand what the underlying cause was (except for the obvious reason the light stays on - the alternator is not charging). So, I tested a little further.
I tested that the exciter wire going from the ignition switch to the alternator was not grounded prior to the alternator (the ignition warning light is part of this circuit). If it wound be grounded current could flow and the light would be on. No grounding.
I then tested if the alternator was delivering battery voltage to the exciter wire, once the car had been started and the alternator was charging. With ignition on but engine off 12v is delivered through the exciter wire to alternator. This makes the led light up and it delivers voltage to excite the alternator to start producing a charge once the engine is running.Once the engine starts, the alternator is self-exciting and generates 12v back through the exciter wire, which balance out the 12v coming form the ignition switch. And thereby the Led light goes out once the engine is started.
I did not find 12v coming from the alternator to the exciter wire. Also, the alternator stopped charging as soon as cut the connection between the alternator and the exciter wire. I found my problem.
The alternator regulator (a module within the alternator) sense the battery voltage and the load on the system in order to adjust how much the alternator should generate and it receives the initial 12v to excite the alternator to start charging. Once it has started to charge it is self-exciting, and it sends voltage to the exciter wire. This was not happening on mine.
So, despite having an alternator charging as it should. It was faulty.
I replaced just the alternator regulator, which sits on the back of the alternator under the plastic cover. It now self-excites, delivers 12v to the exciter wire with engine running and the ignition warning light goes out once the engine starts.
So, this might be the cause of the led glowing despite having a charging alternator. To test it I made a loop with a couple of wires with alligator clips on. I did not want to disconnect the exciter wire with the engine running and potentially cause a short. Hope this might be help if you have this symptom.
Cheers
Michael
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