Hi Brian

As Roger said, that's a sod .

If the fridge and booster has previously worked correctly then there may be a problem with the split charge relay in the car. Some 'smart' relays have an adjustment to vary the switching threshold and it would be worth testing its output with your voltmeter.

Otherwise you'll need to check the wiring's correct at the 13 pin junction box under the van.

There are 2 x white sheathed 2-core cables that run from the junction box. One cable feeds permanent 12v for leisure battery charging (input to booster) and the other is ignition-on (D+) which energises the booster and also supplies the fridge via the BIP's fridge relay.

If you need any further help you can give me a bell.

Quote: Aaron Calder wrote in post #4

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The car has Westfalia dedicated electrics hidden somewhere behind a panel in the boot and there's no way I'd dare muck about with that.

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Quote: Aaron Calder wrote in post #6

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Or am I, as so often is the case, missing something?

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Quote: Aaron Calder wrote in post #8

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But when the ignition is off, the lights on the fridge and the booster go out so it shouldn't be a problem.]

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Quote: Aaron Calder wrote in post #1

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This morning with the aid of my glamorous assistant cum holiday ironing contractor, I have been checking what happens electrically when the caravan is attached to the car.

1. EHU connected, car ignition off - green light on fridge on; red light off; green light on Schaudt booster off; 13.8v on voltmeter

2. EHU disconnected, car ignition off - all lights off; 13.7v

3. EHU disconnected, car ignition on; engine not running - red light on fridge on; green light on Schaudt booster on; 14.3v

4. EHU disconnected, car engine running at idle - red light on fridge on; audible click from Schaudt booster and green light on booster on; 14.3v

5. EHU disconnected, car engine blipped to 2000rpm - exactly same as 4 above.

I am now confused as it would appear that when the van is attached to the car with the ignition on, there is power to the fridge and booster whether or not the engine is running. I had expected the booster and the fridge relay to kick in as the engine revs rose but it didn't appear to make any difference.

This would suggest that if I were to turn off the engine but omitted to turn the ignition off, I would risk draining the car battery. It's not what I expected to find.

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Glamorous assistant or electrics?

🤔

Apparently I'm a banksman (for reversing), useless navigator, expert curry cook, sommelier (wine whatsit for them what don't parlez the French), keeper of the cash and the font of all knowledge. I think he may be creeping with the last one, wonder what he wants?

Electrics

Simple way to check your car electrics.....

Take the locating lug inside the socket on the car as 6 o'clock. 5 mins past the hour is pin 9 and should have a permanent live feed. 10 mins past the hour is pin 10. This is the fridge feed and should be dead until the engine is started and the alternator gives a higher enough voltage to operate the relay, ffitted as part of the car towing electrics, and then goes live.
Turn off the engine and you should see the voltage on this pin drop until the relay releases and the feed goes dead.
Anything else means the car electrics are wired up incorrectly....
Ian

Quote: Addick100 wrote in post #14

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Simple way to check your car electrics.....

5 mins past the hour is pin 9 and should have a permanent live feed. 10 mins past the hour is pin 9.

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