Help needed with finding D+ signal on my 2001 2.8Hdi Peugeot Boxer based Pilot Galaxy 270. (1 Viewer)

[68c]

Struggling with working out how to find the D+ alternator signal. Van has been OK since I got it last year, or so I thought. After leaving the Omnistor step out and clipping it on a grass verge I removed it to repair and straighten. I was suprised to find a microswitch which was seized in the closed position. After some research it appears this is part of a step out warning and auto retract, I found the auto retract relay hiding in a cupboard. Keen not to have a similar accident I bought a new switch hoping to get a warning and auto retract, now if I turn on the ignition with the step out there is a buzzing sound followed by the step immediately retracting. I had not started the engine. I expected it to only auto retract when starting the engine, in the same way the split charging and refrigerator relays work from the alternator D+ signal. Delving deeper I found both the split charge relay and fridge relay also activate as soon as I turn on the ignition. As this is a twenty year old van I am unsure if this was how it was built or it it had been tampered with somewhere down the line.
It seemed a simple matter to change the signal to the auto retract relay from ignition live to alternator D+, this would only feed the relay coil so should not be a problem. However, looking at the alternator output I can only see the main power lead and a smaller lead consisting of two thin wires going to a junction plug. Research suggests some alternators do not have a D+ terminal, instead an earth is produced when the engine runs. I cannot detect any change to earth or voltage appearing on either terminal, the only thing that happens is the charge warning light does not come on with it unplugged.
On a previous van I fitted a Voltage Sensing Relay instead of a split charge relay etc. Worked fine until I added solar power when it would raise the voltage sufficient to connect the cab and hab batteries. I never did sort that out so went back to a split charge relay.
Not sure how to proceed from here.

 

[SandraL]

I think you will find the d+ is not a true only live when engine running and is actually an ignition on signal in most conversions. Now waiting to be corrected.......

 

[pappajohn]

At 20 years old yours may be connected to the ignition switch output which would explain the way its working .
Turn on the key and it becomes live.

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[63720]

I had a similar step issue and found the buzzer under our Fiat Ducato driver's seat, after a helpful tip from someone here, connect to a D+ relay. Our step is not auto retract, I still need to press the button.

 

[68c]

My worry now is that the split charge relay and the fridge relay also come on with ignition live. Not a problem if I remember not to sit with the ignition on. I would still like to find a way of having an engine running signal, I may try doing something using the oil pressure switch, perhaps fit two.

 

[Nasher]

How about a Voltage Sensitive Relay (VSR)?

Something like a Durite 0-727-33 - it would connect at 13.3v

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[mitzimad]

You could use a smartcom relay on the feed you already have and use that to trigger the existing split charge and fridge . Power would go to the smartcom but not switch untill the voltage went up when the alternator kicked in
smartcoms dont have a good reputation as they are rated at 30amps and not really up to it but switching another relay will draw very little power so fine for that job also they are adjustable at what voltage they make

Smartcom Voltage Sensing Split Charge Relay 12V / 30Amp

Split Charge Relay, Voltage Sensing Relay

brocott.co.uk

 

[SandraL]

How about a Voltage Sensitive Relay (VSR


If starter batt is charged by solar or mains it could cut in without engine. Once parked next to a van with aftermarket daylight running lights that were controlled by sensing voltage, sunny day with solar charging they were often on when parked.

 

[68c]

How about a Voltage Sensitive Relay (VSR)?

Something like a Durite 0-727-33 - it would connect at 13.3v

The problem is solar charging causes it think engine is running.

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[autorouter]

How about using a Voltage-sensitive Relay in series with an ignition-controlled relay? It won't come on until the alternator raises the voltage to its trigger level. But it will be off when the ignition is off, so no problem with solar.

 

[68c]

The solar panel will raise the leisure battery voltage to near or above alternator voltage. I forgot to mention there is a battery master fitted which charges the cab battery from the leisure battery. Once the leisure battery is charged it raises the cab battery and triggers a Voltage Sensing Relay. I need to crawl under the van and double check there is no D+ terminal on which case I may look at using the oil pressure gauge earth signal to trigger a relay. Unless O can fond an electrical solution i may have to fit a second oil pressure switch if the oil warning bulb draws too much current.

 

[autorouter]

I can see that my solution using a VSR and ignition-controlled relay won't work if you have a BatteryMaster. Here's another suggestion.

You say the charge warning light works, ie comes on when the ignition is switched on, and goes off when the alternator fires up when the engine is turning. You could connect a relay coil across the warning light, and the relay would change state as the light turns on and off. You'd have to use a small relay with a low power coil, to avoid loading the light circuit too much, and maybe altering its function.

If the relay is a changeover type, you can use the NC (Normally Closed) and COM (Common) terminals. It will be ON when the light is OFF, and OFF when the light is ON.

You can then put it in series with an ignition-controlled relay, to give you an approximation to a D+ signal.

If you are switching a lot of amps, the low power relay might not be able to handle it. You might need yet another relay, high power, with the coil switched by the low power relay.

Edit: In fact you wouldn't need an ignition-controlled relay - connect the ignition feed directly to the COM terminal of the low-power relay.

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[pappajohn]

i may have to fit a second oil pressure switch if the oil warning bulb draws too much current

Where are going to fit a second switch.