Mystery Box (1 Viewer)

[garlicmonster]

Greetings the assembled Hymeristi

Just over a week ago, we bought our first motorhome. It's a 1993 Hymer B654 with a Fiat 2.5 L diesel motor and I need to identify a mystery electrical box I discovered under the bonnet.
Its a circuit board about 6" x 4" and sits (component side down) above the main battery, in a plastic housing
Looking at the state of it, it probably hasn't worked since God was a boy however I daren't take a screwdriver to it to try to get a better look in case it breaks

Could this be the charger control for the leisure battery ?

On my control panel in the kitchen, I have what looks like a battery charge meter (Strom) that is clearly broken (needle remains hard right at all times)

Could the 2 be related ?

As far as I can tell the leisure battery requires a mains hookup to charge from the unit under the driver seat.

Cheers

Allan

 

[flatpackchicken]

Hello and welcome garlicmonster to the site, look forward to your posts and enjoy being a member, also join up for £10 and become a fully subscribed member and it will be the best £10 you will ever spend, as there is a wealth of information on here probably the best in the UK, Sorry don't know much about your hymer but there are many members on here that have one so I expect you will get a few replys to help you out, Regards Garry Flatpackchicken

 

[lorger]

Hi and welcome not to sure what the box is, could be something like a buzz bar where all the cables are connected and this is then connected to the battery.

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[eddie]

Cold you post a photo?

 

[teddybard]

Hi & Welcome

Love the forum name

Roger & Sheila

 

[bigfoot]

I suspect it may be an alarm board. Is there any writing on the board? If its in German its likely itwill be a Hymer part,if its Italian it will be the alarm.

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[garlicmonster]

I hadn't thought it might be an alarm

I'll take some pics and upload them tomorrow

Cheers

 

[garlicmonster]

I hadn't thought it might be an alarm

I'll take some pics and upload them tomorrow

Cheers

 

[garlicmonster]

OK - so here's the mystery box

I can see no writing on it in either Italian or German - the underside is also unmarked but does have some conections underneath - I *think* there's a thick red & black plus some others but I couldn't get a viable picture

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[hilldweller]

That's terrible. Anyone who would do that wants shooting.

 

[garlicmonster]

yebbut

- what is (was) it ?
- what does (did) it do ?

The only thing I cant get to work (so far) is the charging of the leisure battery other than at a mains hookup

 

[hilldweller]

yebbut

- what is (was) it ?
- what does (did) it do ?

No idea. But whoever said "alarm" could have been close, the pcb is complex enough for that.

The only way to find out is trace the wiring.

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[bigfoot]

I agree with Brian,its bad enough to be home made,have you traced the wires back?
Maybe a bit of "Time Team" investigation is needed,can you see any identifying marks on the board components?

 

[eddie]

From memory, it is factory fitted and has a (or should have a ) grey lid (or was it Aluminium?)

Again from memory I have an inkling that it is do do with the glow plugs. Does it have a connector underneath and a much larger red with on to a terminal with rubber boot/cover?

Perhaps anyone with a older Fiat can have a peek under their bonnets?

Eddie

 

[bigfoot]

From memory, it is factory fitted and has a (or should have a ) grey lid (or was it Aluminium?)

Again from memory I have an inkling that it is do do with the glow plugs. Does it have a connector underneath and a much larger red with on to a terminal with rubber boot/cover?

Perhaps anyone with a older Fiat can have a peek under their bonnets?

Eddie

I had a '92 2.5td FIAT My box was a black plastic unit without an,easily,removable lid. I would have expected it to have some identifying marks,probably in German,Hella,Hymer or Bosch.

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[garlicmonster]

Hi Eddie

It does have a grey plastic lid and thick red / black wires plus a number of thin black ones.

If its glow plug related, I'd best put the lid on and apply duck tape to secure

Cheers again

 

[pamella]

just reading your post.we brought a 1989 hymercamp56 on a talbot peugeot chassis.
our battery had its charger sat next to it.we are waiting to run the battery down to see if the engine battery will charge it.
will keep an eye on your thread to see what it is,will also have a look under our bonnet at the weekend.

 

[eddie]

I am pretty certain that it is the timer for the glow plugs. Pop the lid back on and tape it up:thumb:

Cheers

Eddie

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[hilldweller]

I am pretty certain that it is the timer for the glow plugs.
Eddie

Do you this you should change "is" to "was". That is one manky looking unit, is that a rotting relay underneath ?

At least he'll know where to look if it won't start in cold weather.

 

[Wildbill]

Heater plug units usually make a click when the plugs are hot so get someone to turn on ignition and listen for the click of the hater plug if it starts good on first crank there is nothing wrong with your hater plugs unit there is a good chance that it is the leisure battery unit as it is siting over leisure battery only my theory

 

[stcyr]

The mystery box is a cold start device. Operates the glow-plugs or flame-start device (depending on engine make). Our 2.5TD Fiat has flame-start as opposed to a glow-plug in each cylinder. It's similar to a normal glowplug but when activated, heats up and a solenoid next it injects diesel through the plug which , erm, flames

See Beru website.

If it fails you can connect a wire from battery + to glowplugs/flamestart ... and ... whip the wire off quick or it'll melt

By the way, if flamestart is fitted as opposed to normal 4 glowplugs, there is no need to wait for the light to go out (indicating combustion chambers are heated) before turning starter - just turn key to start in one movement like a petrol engine...

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[eddie]

Heater plug units usually make a click when the plugs are hot so get someone to turn on ignition and listen for the click of the hater plug if it starts good on first crank there is nothing wrong with your hater plugs unit there is a good chance that it is the leisure battery unit as it is siting over leisure battery only my theory

Hi Bill, no, it is factory fitted, above the engine battery on the off side inner wing.

Eddie

 

[garlicmonster]

>The mystery box is a cold start device.

Ok - what sort of temperature might this be needed ? I'm not at all confident that it's functional but don't anticipate going anywhere if I need to scrape ice from the windscreen first

 

[mid4did]

i have a fiat ducatto based 1994 dethleff.This is what I have with the cover complete.I also get a heater plug light when started from cold.
magnet marelli
rep 5A
12v COD
64806050.
Hope this may help.
pete

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