Thread: EDIC wiring help please

So you have a 12V system, running a 24V EDIC?

What I'm led to believe is that 24v components require the higher voltage to get the work done, and results are flakey at best when the components don't get enough voltage. How hard is it to source a 12V edic? Alternatively, do you have a second battery you could make a 24V circuit from to drive the edic on it's own circuit?


Just on a quick look, but the resistor in your pic is doing nothing other then creating a resistance. Resistors by nature get hot, as the 'resistance' they give is shed as heat (in comparison a resistor in a headlight circuit is a globe, which gives off light).
If you were running a 24V vehicle electrics and a 12V EDIC, then the resistors would be between the relay and the EDIC on both red wires in your diagram.

Yeah, I've always intended to fit a 12v EDIC, but just haven't got around to it.
Being time poor, I was just hoping for a quick solution for the time being.

I do have dual batteries, but how do you create a 24v circuit for an individual device from a 12v system.

Cheers, Murray

What the resistor is doing is dragging down the ignition circuit voltage when the key is turned off and the alternator warning light is illuminated on the dash. The alternator is still producing voltage so the warning light is back feeding some voltage to the relay. Pressing the brake pedal causes the brake light globes to take place of your resistor and drop out the relay.

Some suggestions:

1. Fit a 10-20W globe in a box instead of a resistor.

2. Fit a resistor capable of handling the current needed.

3. Fit a smaller globe to your alternator warning light so it doesn't pass enough current to hold the relay on.

4. Fit a diode into the alternator warning light wire so that current only flows from the ignition switch to the alternator, not the reverse. A 1 amp diode should suffice with anything up to a 10W warning light globe. This would be my choice of solution as nothing else needs to be changed It will not affect the alternator's function.

Originally Posted by bee utey

What the resistor is doing is dragging down the ignition circuit voltage when the key is turned off and the alternator warning light is illuminated on the dash. The alternator is still producing voltage so the warning light is back feeding some voltage to the relay. Pressing the brake pedal causes the brake light globes to take place of your resistor and drop out the relay.

Some suggestions:

1. Fit a 10-20W globe in a box instead of a resistor.

2. Fit a resistor capable of handling the current needed.

3. Fit a smaller globe to your alternator warning light so it doesn't pass enough current to hold the relay on.

4. Fit a diode into the alternator warning light wire so that current only flows from the ignition switch to the alternator, not the reverse. A 1 amp diode should suffice with anything up to a 10W warning light globe. This would be my choice of solution as nothing else needs to be changed It will not affect the alternator's function.

I tried the light globe as well as a resistor, and both work well, so a light globe is definitely an option.

Regarding the diode idea, would you fit it directly behind the warning light in the dash, or is there a wire off the alternator that goes straight to the warning light, I'm just thinking of easier access to give it a try. I have a Hitachi alternator.

Thanks for your suggestions.

Cheers, Murray

Originally Posted by rijidij

Regarding the diode idea, would you fit it directly behind the warning light in the dash, or is there a wire off the alternator that goes straight to the warning light, I'm just thinking of easier access to give it a try. I have a Hitachi alternator.

The wire from the charge light should be continuous to wherever the voltage regulator for the alternator is. If your Hitachi alternator has an internal regulator then the same wire will appear there too. However behind the dash is subject to lower heat and vibration so if you can easily fit the diode there then all is good. Basically anywhere you can see that wire in the loom you can cut it and solder in a diode. Find a wiring diagram to identify the correct colours on the wire and follow the loom to where access is easy.

Any electronics shop will have a suitable diode for approx $1. Mount the diode so that the end marked with a ring is on the alternator side.

Unless you've changed something in the electrical system and this has just randomly started happening, I would be looking for a poor earth connection. Tried jiggling and cleaning the EDIC and relay connectors for a start?

Possible way to test another earth issue - Switch key off. Leave engine running. Take a clip lead or length of wire in the engine bay and try touching the EDIC earth against another known good earth. If earthing the earth makes the engine shutdown, you know the earth is bad.

OR use a multi meter to check for voltage between the EDIC earth and another earth point. Should be zero.

I hope all that makes sense!

Originally Posted by Judo

Unless you've changed something in the electrical system and this has just randomly started happening, I would be looking for a poor earth connection. Tried jiggling and cleaning the EDIC and relay connectors for a start?

Possible way to test another earth issue - Switch key off. Leave engine running. Take a clip lead or length of wire in the engine bay and try touching the EDIC earth against another known good earth. If earthing the earth makes the engine shutdown, you know the earth is bad.

OR use a multi meter to check for voltage between the EDIC earth and another earth point. Should be zero.

I hope all that makes sense!

Thanks, I did connect a 'fresh' earth when I was testing things as a poor earth was the first thing SteveG suggested when we were pondering the problem on a recent camping trip, but I will test this again more thoroughly before proceeding with anything else.

Cheers, Murray

Bee utey is almost certainly on the money.