HYMER B544 CONTROL PANEL PROBLEMS

[Alisdair]

Good evening,

I am a "rejoiner" to this forum and am now posting about a problem similar (but, crucially, not the same as the forum helped me with a couple of years back.

Our RHD 1999 Hymer B544 has an EBL 4 -105 electroblock and a control panel of type 104.

On starting to sort our van for our Easter trip, I discovered that the main switch on the panel no longer lights up - and there is no power to the internal lights, fridge light and (presumably - although I have not tried) the heater.

I have tried:

a. Checking all of the blade fuses in the Electroblock - all OK.
b, Checked the blade fuses next to the Leisure Battery (in our case under the passenger seat) - both OK.
c. Checked that there is power at the Main Switch (there is).
d. Checked that both batteries are fully charged - they are, and curiously, the battery indicators on the panel work as expected.
e. Bypassing the main switch - although this may have risks - still no joy!

I'd be grateful for any idea as to what else I need to check.

 

[Figaro]

No expert, but sounds to me like a fault in the control panel.
I'm sure someone with more tech knowledge will be along soon.

A & N caravans and Aplujack engineering provide a repair service for these items I believe

 

[Lenny HB]

How did you check the fuses, a look is not good enough they need checking with a meters.

 

[Alisdair]

Hi Lenny,

Please don't flame me for what must seem a very dumb question - but what I did was take the fuse out, and check that it was intact.

How would I check the fuse with a multi meter?

 

[Lenny HB]

Hi Lenny,

Please don't flame me for what must seem a very dumb question - but what I did was take the fuse out, and check that it was intact.

How would I check the fuse with a multi meter?

Multimeter on ohms setting put one lead on one of the fuses blade and the other lead on the the other blade it should read zero or almost zero.
If you put the two meter leads together they should read the same as across a fuse.

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[Alisdair]

Ah, thank you! Every day is a schoolday!

 

[ctc]

I have a separate switch that turns off all the 12v. A possibility perhaps?

 

[1967bowesj]

Hi Alisdair are you saying the main switch has 12v to it?
Is the switch mechanical or electronic?
If there is 12v positive to switch then the lighting up part must be down to poor return negative side.

Daft bit but you haven’t had and cable munching mice in have you? They love cable

 

[autorouter]

I'm assuming that the EBL model number is 105-4, not 4-105. The 12V power is in two sections. The electric step and the heating are powered from a different point than the rest of the electrics (lights, pump TV etc, so you could see if they are working or not.

Also check both ends of the 8-way data cable from the EBL front panel to the display panel, to make sure they are fully inserted and haven't come loose.

The Main Switch that you mention, is that the switch on the display panel or the isolation switch near the leisure battery?

 

[Alisdair]

Autorouter, you are correct - the EBL is model 105-4.

The switch is on the RHS of the panel shown here. It appears to be mechanical.

Confusingly, the left hand side of the panel works - that is, the tank test button and battery test button; the right does not. This might suggest that there is a loos connector somewhere. I'll try both of your suggestions later today - thank you very much. I'll also check the fuses.

As far as I can see, there is no other 12V isolator - apart from the fuses at the leisure battery - as I said in my OP they seem OK.

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[Alisdair]

Further to my last post, I have checked that the heating works - it does. This suggests that one half of the panel is OK. This picture is of the rear
of the switch panel - the "Hauptschalter" is the switch giving me grief. When I test the green as +ve and the blue wire as negative, I get 14V (the van is currently plugged in). When I put my meter to the yellow as +ve and the blue as -ve, I get almost no reading.

I have tried all of the connectors to the fuse board and the EBL -they all seem sound.

Any other suggestions would be most welcome!

 

[autorouter]

In case you haven't got it, the manual is available here:

https://res.cloudinary.com/lci-cloudinary/image/upload/v1694803226/lippert-eu/support/power-on-board/pdf/anleitungen/911/9110406/911406_20040316_EBL4-105_BA_EN.pdf

The original manufacturer Schaudt was recently merged with Lippert.

At the end of the manual is a wiring diagram of the EBL. There is a relay which switches the power on and off. It is labelled the Hauptschalter (Main switch) relay. It is a bistable latching relay. It switches the power to most of the habitation circuits. Everything except the step, heating, compressor fridge and solar panels.

A relay is an electrically operated switch. This relay is unusual, in that it has two stable positions, on and off, and a pulse from the panel switch flips it from one state to the other. This relay is located inside the EBL. You can see that the wire to the panel switch is quite thin, by no means thick enough to carry all the main current. The switch only switches the very low power to the relay coils, which switch the main power contacts of the relay.

This relay can fail, ie not flip from one state to the other. If one of the relay coils fails, it will switch off, but not on - or the other way round.

This problem has come up a couple of times recently.

EBL104-3 not turning on

Hi hope someone can help, my EBL wont turn on when i press the on button at the habitation control panel, however i can reach under the drivers seat and flick the relay on in the EBL. I have continuity checked from the control panel to the EBL and all seems to be good. hte off switch will work...

www.motorhomefun.co.uk

Elektroblock latching relay help needed please.

Hi and thank you for letting me join. I see there are some electronics wizards here who I'm hoping can help me! I have an Elektroblock EBL104 in my Hymer which won't switch back on from the wall panel. I've traced it down to the bi-stable relay which shows 600ohms on the "off" coil and 90...

www.motorhomefun.co.uk

The exact relay is no longer available, but A&N Caravan Services say they can replace it with a modern version which does the same thing, but a small modification is needed. There is another company called Apuljack Electronics that does this kind of thing, and I'm sure would also do this.

Motorhome/Caravan Servicing, repairs for most Battery Chargers

Most Motorhome/Caravan Battery chargers repaired. Schaudt Elektroblock, Nordelettronica, Calira, Arsilicii, Toptron, Plug In Systems and Burstner Reich E-Box repairs a speciality.

www.aandncaravanservices.co.uk

Apuljack Electronics

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www.apuljackelectronics.co.uk

I don't know where your EBL is mounted, but maybe you can do as suggested in one of the threads, and manually change the relay to its ON state. You could do that to get you through your holiday, and get it fixed when you get back.

 

[Alisdair]

Hi, that's really helpful. I will have look later today and see if I can identify the Hauptschalter relay.

The EBL is mounted to the right of the driver seat - so not sure if I will be able to access it.the relay easily. But, worth a try.

 

[Alisdair]

Good morning,

I managed to get the EBL out of the van, and opened it up. Electronics is most definitely not my strong suit - however, would i be right in thinking that the black box with a red slider in the centre of the photo is the relay in question?

 

[autorouter]

I think you're right about that. Compare it to the relay in the photo in post #1 of the second thread I linked to. jon Jenner says he is having a go at fixing it

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[Alisdair]

OK, thank you - I'll give that a go - and report back - because this seems to be a popular topic right now!

 

[Alisdair]

Well, the good news is that this worked. By flicking the little red switch, everything in the van now turns on. Thus our trip is sorted. And, I will deal with the replacement relay after this. Thank you to everyone who helped me. However, I have a follow on question - the Main Switch light now lights up. If I touch this switch, will this reset the relay , (and require the whole process to be gone through again?

1.

 

[autorouter]

Well, the good news is that this worked. By flicking the little red switch, everything in the van now turns on. Thus our trip is sorted. And, I will deal with the replacement relay after this. Thank you to everyone who helped me. However, I have a follow on question - the Main Switch light now lights up. If I touch this switch, will this reset the relay , (and require the whole process to be gone through again?

Good to know that a workaround for the problem exists. How easy is it to flip the little red switch? Did you have to open up the EBL, or is it accessible from outside?

I would think that the coil to switch that relay off is probably still working, so pressing the Main Switch on the panel will probably turn everything off again, so you'll have to switch on at the red switch again.

 

[Alisdair]

Good to know that a workaround for the problem exists. How easy is it to flip the little red switch? Did you have to open up the EBL, or is it accessible from outside?

I would think that the coil to switch that relay off is probably still working, so pressing the Main Switch on the panel will probably turn everything off again, so you'll have to switch on at the red switch again.

Unfortunately you have to take the EBL out of its mounting, and open up the case. It's a pain, manly because the difficulties of getting the wires reconnected- but at least there is a workaround. Curiously enough, when I tried to isolate the EPL by disconnecting the leisure battery fuse, it didn't turn off. So there's more going on here than meets the eye! I will not be touching the main switch any time soon!

 

[autorouter]

That main switch relay is a latching relay, that has two stable positions, off and on. Most relays aren't like that.

A standard relay has a single coil, which generates a magnetic force. When the coil is energised, the magnetic force pulls two contacts together, overcoming the spring which is trying to pull them apart. When the coil is not energised, the magnetic force disappears, and the spring pulls the contacts apart. If all power is removed from the relay, the spring pulls the contacts apart. All the time a standard relay is on, the coil is energised, and is consuming power - only a tiny amount, but it can mount up over days or weeks.

A latching relay has two coils, on and off. The contacts have a mechanism that is stable in either the on or off positions. The coils generate a magnetic force to flip it from one stable state to the other. The relay remains in its last state, on or off, even if all power to it is removed. The coils only consume power when actually flipping the relay from one state to the other. Most of the time both coils are not energised, and don't consume any power at all.

Your main switch relay should stay in the on state until the off coil is energised to flip it to the off state. So as long as you don't touch the switch on the panel, you should be OK.

In my Hymer, I hardly ever turn the main 12V power switch off. Even in storage mode on the drive, it's connected to EHU, so no problem with draining the batteries over a long time.

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[Alisdair]

That's all really useful advice thank you. Did occur to me that I could disconnect the main switch temporarily until the latching relay is replaced? This would prevent me turning off by "on force of habit "!

 

[Pinoypaddy13]

Hi all am new to motorhomefun and am reading Alisdairs’ thread I have the exact same trouble with my MH and am just wondering Alisdair did you get the relay sorted when you got back from your Easter break?