Interior lighting - Autosleeper Mezan - auto off during driving

[AdamCairns]

Hi, my first post:

Have a Mezan 2006 lowline

 

Normally when you start the engine, the interior lights,(all the 12v circuit) by design go off ; conversely when you switch off the engine, the 12v cabin circuit is restored. Mine on occasion, doesn't do the latter meaning when you are coupled to 240 v. the PSU is running the 12v circuit, I have to assume without the leisure battery in circuit - not ideal.

 

Can anyone tell me where this relay is located if it isn't incorporated in one of the two engine-bay relays - one of course activates the fridge circuit.

 

Does the split charging one also include the ability to isolate the interior (12v circuit) when running?

 

Many thanks - I was hoping it might be a mechanically sticky relay......

[PJay]

Why would the lights be on , in the first place??

PJay

[Derek Uzzell]

Welcome to the Out&AboutLive forums.

 

The normal arrangement with UK-built motorhomes of the early-2000s would be to have three separate relays – a split-charge relay, a fridge relay and an ‘isolation’ relay.

 

The isolation relay disables certain habitation equipment (eg, reading lights and hob gas-igniters) when the motorhome’s engine is running and was introduced in the late 1990s when there was concern (in the UK at least!) about electro-magnetic compatibility (EMC) between the base vehicle’s electronic control systems and the electrical equipment installed by the motorhome converter.

 

Motorhome builders don’t follow any standard practice when it comes to where relays are installed. Your Mezan has obviously got something that isolates the habitation lighting while driving and I’d expect the isolation to be performed by a dedicated relay. Unfortunately I can’t tell you where to look for it.

 

Mezans will be relatively rare, so you may not get a definitive answer here. If that turns out to be the case, you might try the Auto-Sleepers Owners Forum

 

http://www.autosleeper-ownersforum.com

 

 

[AdamCairns]

Hi Derek, thank you for that suggestion.

 

Having researched a little further, it looks like the Sargent PSU may well have this isolation relay inbuilt, perhaps sensing a voltage differential when alternator operates, rather than from the 'blue' sensing wire (split relay activation) supply from the alternator - for no such wire appears to enter the Autosleeper-fitted harness.

 

Good idea about the Autosleeper forum, will give that a go

 

Thanks again

 

Adam

[paulmold]

Sargent are especially good at giving advise/help, so why not give them a call and talk them through the problem.

[Derek Uzzell]

AdamCairns - 2016-05-22 12:12 AM

 

Hi Derek, thank you for that suggestion.

 

Having researched a little further, it looks like the Sargent PSU may well have this isolation relay inbuilt, perhaps sensing a voltage differential when alternator operates, rather than from the 'blue' sensing wire (split relay activation) supply from the alternator - for no such wire appears to enter the Autosleeper-fitted harness.

 

Good idea about the Autosleeper forum, will give that a go

 

Thanks again

 

Adam

 

I notice you’ve asked about this on the ASOF

 

http://www.autosleeper-ownersforum.com/t17826-cabin-supply-isolation-relay

 

and I’m sure the advice given there is correct and that the isolation function is built into the Sargent electrical control system.

 

Having roamed around the internet a bit I think that a Mezan would have an EC200 system. This is described here

 

http://www.sargentltd.co.uk/PSU_2007_User_Instructions.pdf

 

and the “12v Power turns off” section on Page 4 advises "Engine has been started, all equipment has been disconnected to meet EMC requirements”. Page 11 shows where the "Engine running signal (from alternator” connects to the PSU.

 

As failure to restore the 12v habitation-area’s functionality is sporadic in your Mezan’s case, paulmold’s advice to contact Sargent makes good sense. Realistically, if the problem lies within the PSU, you may well not be able to fix it yourself.

[aandncaravan]

Not familiar with your vehicle, but you can find an EC200 wiring diagram (Swift version) posted on the bottom of our Sargent web page : http://www.aandncaravanservices.co.uk/sargent.php

 

From the wiring diagram it isn't clear which elements are inside or outside the Sargent box, but I suspect the 'driver' cable for the EMC relay is an offshoot of the Red/Yellow wire from the 'Split Charger' Relay/Fuses. This fuse also drives the Fridge so you can't just disable/remove that fuse, but if you trace the wire to the EC200 unit you may find the Red/Yellow splits off just before entering the EC200 to activate the EMC relay inside??

To see if this is the right way to go, just as a test as you may also lose the Fridge, pull the Fuse that has a Red/Yellow wire running from it. If the habitation lights stay on when you start the engine, you have a starting point.

 

If you put a new fuse in that 'Offshoot' wire just before it goes inside the EC200 it may then be possible to pull the fuse to disable the operation of the EMC relay altogether, which serves no function from what we can see.

None of the Continental Motorhome builders disable the interior electrics once the engine starts.

It was a British Directive (driven by the as was Post Office) to limit Electromagnet radiation from moving vehicles. Yet the Directive was already out of date before it became 'law'. Electronic Ignition and other Electronic devices became standard fitment on cars as the 'Bill' was being passed. Tax Radios, Mobile phones, etc followed soon after.

With mobile WiFi and Bluetooth now being common the directive is a bit of a nonsense.

 

If the habitation battery gets a bit low on a Continental built van, a Rimor owner can start the engine to boost the battery in an emergency, like being able to see the last laps of F1 race, etc.

But on a British built vehicle everything shuts down and you sometimes can't even see how much charge the Alternator is putting into the battery!!

 

 

As stated above I have not worked on your vehicle so don't know if the wiring diagram applies, but many of the other Sargent equipped Motorhomes use a similar setup, so start under the bonnet looking for the 3 fuses next to the 'Split Charge' and Fridge relays. Email if we can help, see Contact Us page.

 

 

 

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