Tricky electrical question

[Silenceisgolden]

I hope someone can help. My '97 6x6 had a dreadful mess in the wiring, lots of 240 volt type flex held on with masking tape, etc etc. I ripped it all out and completely rewired it.

Everything works fine, but.....after switching off, the brown/yellow wire from the alternator that feeds the alternator warning light provides just enough current to prevent the EDIC relay from from shutting down the engine. I can stop the engine by any little load on the ignition controlled loads, such as the heater etc, but clearly something is wrong.

With the ignition off but the engine running, I measure 4.7 volts on the 'ignition' line, just enough to hold in the EDIC relay thus preventing shut down. If I disconnect the brown/yellow wire from the alternator it shuts down happily.

When I pulled out the old wiring, I found a resistor mounted in an in-line fuse holder tucked away behind the instruments. It measures about 93 ohms.

The wiring diagram shows a resistor between the brown/yellow wire and ignition on power, presumably so the alternator will still get its exciter power if the alt globe blows. I am wondering if maybe this resistor should go to ground to load the brown/yellow wire down enough to release the EDIC relay.

Does anyone please have any thoughts on this?

Many thanks for any info.

Cheers,

Paul

[Blknight.aus]

youve done one of the following with the diode

1. missed it out
2. put it in backwards
3. its dead.

[Silenceisgolden]

Ah, so it is a diode and not a resistor - or it should be a diode. It measured 93 ohms both ways.....

Many thanks Dave, to the rescue again!

[Blknight.aus]

Ah, so it is a diode and not a resistor - or it should be a diode. It measured 93 ohms both ways.....

Many thanks Dave, to the rescue again!

its both a diode and then a resistor when it fails closed.

heres the wiring break down... where it gets fun is the way it back loops if you open it...

the missing colour feed is from the engine plug back to the green line IVe got going to the common plug... thats the wire that powers up all the warning lights.
149227149228

[Silenceisgolden]

Thanks Dave for the diagrams. I think mine being a Bushranger build is slightly different. The one device mine had was either a blown diode or a resistor - on the circuit diagram for this model only a resistor is shown, not a diode.

However, to further compound the problem this morning I removed the diode/resistor (hereinafter called device) and again it refused to shut down. The voltage without the device was now only 2.4 volts but was again enough to hold in the EDIC relay. Without the 'device' though, I had to rev the engine fairly high before the alternator cut in, so it seems this device is needed.

I can simply put a resistor across the EDIC relay coil to bleed off a few volts, but there was no problem before I rewired....

Again, thanks Dave for your advice. If taxpayers money paid you to learn, then for once my taxes were well spent!

Cheers,
Paul

[Silenceisgolden]

Found it! The original circuit has an 'ignition control relay' that powers some of the accessories. The current drawn by its coil loads down the alternator light wire enough to allow the EDIC relay to shut down.

Phew!

[Blknight.aus]

the diode is to allow the current to flow into the alternator to do the excitation and warning light business, but to stop back feeding the EDIC relay.

[Silenceisgolden]

Again, thanks Dave as always you make perfect sense. I will whack in a diode.
Cheers, Paul