Jump to content

Fiat Ducato - missing relay in engine bay? (Mclouis/SEA)


Recommended Posts

Hi everyone - first time on here as a new motorhome owner,


I have a 2004 SEA / McLouis 620 plus and hoped some one can give me some help with the electrics...

we bought it last summer in the August mid season/pre reg price dip :-) and despite a few minor issues everything seems to work (apart from the air con) and we have done several trips already, and love all the Kit it comes with.


But there is a missing relay from what looks to be a piece of motorhome wiring right next to the battery (manifested as a random relay socket on a bunch of wires near the battery.)


Ideally a mclouis wiring diagram or SEA standard setup for wiring would be ideal?


Just wondered what's supposed to be there, one thing it doesn't seem to do is charge the vehicle battery while hooked up - is that normal. also it occasionally seems to get a flat leisure battery and we are not sure if its us doing some thing daft or part of the problem?


Ta. all


John B


PS if anyone knows where to get Mclouis ceiling board from we need one.


Link to comment
Share on other sites

Welcome to the Out&AboutLive forums.


This link is to a 2011 request for a wiring diagram for a 2004 McLouis motorhome




You might try sending a PM message to user “pkc” (who still seems to be an active forum-member) who replied to the inquiry.


It’s reasonably common with motorhomes for the ‘vehicle-battery’ not to be charged by the on-board charger when the motorhome is connected to a 230V mains power-supply. Sadly, when this capability is not provided, it’s also pretty common for there to be no warning about it in the motorhome’s handbook


If there’s nothing in your motorhome’s handbook about this, and you don’t get a simple Yes or No answer here, you might try the MotorHomeFacts forum that has a dedicated McLouis section.



Link to comment
Share on other sites

You will probably find with everything switched off the habitation equipment is drawing around 50 mA quiescent current from the leisure battery. The Water boiler is permanently connected to the battery and accounts for some of the current and the control panel and control box the rest. It will flatten your battery in about a month. Make sure you do not leave the heater fan switched on as it s also permanently connected to the battery and it will drain the battery in a few days.

In this vintage of McLouis/SEA you are best to fit an isolation switch in the negative lead of the leisure battery and when fully charged switch it OFF to isolate the battery. (Unless you have solar panels which will keep the batteries charged).

As to the relay next to the starter battery, no idea although may be something to do with the air conditioning and been removed to isolate the air conditioning as the air conditioning gas needs recharging. Just a wild suggestion.

Other than that could be a mod someone has done but on vehicles I have seen there is no relay near the starter battery.

Link to comment
Share on other sites

Hi John,


I'm assuming by your wording that the habitation battery DOES charge when the engine is running. please can you confirm?


So if the hab battery is charging the only other usual relay in this location would be for the fridge to run on 12 volts. So does the fridge work with the engine running and its 12 volt setting selected?


If not it may well be due to the missing relay but do bear in mind it may have been removed because of a fault either in the fridge or wiring. Best to check before replacing the relay.



Link to comment
Share on other sites

Hi all thanks for the info I will go look at that diagram in a mo, as for other bits the fridge and battery etc all work and charge when driving. One other curious thing is all the wiring is blue making tracing stuff impossible also the battery is loose under the drivers seat is there a standard fixing?



Link to comment
Share on other sites

The battery should be sitting in a galvanised metal tray and held with a clamp ( bit of bent metal and bolt) on battery base. Maybe the battery is larger than standard fitted one and clamp did not fit, or indeed does not have a clamping bar along base of battery. I would advise you find some way of clamping down with a bracket or a strap over top.
Link to comment
Share on other sites

The fridge relay and charge slave relay are fitted in the module behind the habitation fuse box. It is probably located behind the passenger seat in the end of the locker facing forward toward back of seat.

It is possible it shares space with water tank and wiring will be all stuffed in so be very careful if removing to inspect as cables in connectors could be easily damaged and needs to be put back in carefully so there is no stress on the PCB from the cables.



Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...