Truma Combi 4 Help Please

davidathomas42

davidathomas42

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So my new to me van. A month and 3-4 uses from picking it up from the dealer the Truma will not turn on.

Been back to dealers twice. Tested all the power into it etc with multi meter and seemed ok. But when you flick the wall switch on to gas or electric nothing lights up. He ordered a new switch and plugged it in and nothing still.

Next step he says is Truma but they are not open until the 4th Jan and I’m booked away all New Years.

If On EHU I have a 240v fan heater I can use but off grid which was my plan I have no heating or hot water other than gas hobs which for sleeping is obviously a no.

Anyone got any guess’s?

Im in the van now with my multi meter and tools searching out fuses ans generally shaking stuff.

A side note that I don’t imagine related (fiat Ducato) the cig and 12v power socket in the van are also not working. They used to. But I can’t find the fuse for them. Tried the engine bay as suggested on google and they are ok at the ones mentioned.

I have not used them since a stereo fitting so they may have disturbed them. Bit pretty sure I have used the heater since the stereo fitting.

Anyway. Any ideas?


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Have you got 12v to the heater?
 
ATM you photo shows set to 60'C hot water Only on electric hook up.

For gas only set LH knob to fully clockwise flame + 60'C and RH knob to centre Flame.

Assuming gas to hob and gas tap to truma on.

What happens then?
 
NicM said:
Have you got 12v to the heater?
Click to expand...
I’ve not got my meter on that yet. I’ve just gone thru every fuse I can find and they are all good. I don’t know where or why the cab sockets are not on yet. I’ve put the multi meter into them and they are dead

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RandallC said:
ATM you photo shows set to 60'C hot water Only on electric hook up.

For gas only set LH knob to fully clockwise flame + 60'C and RH knob to centre Flame.

Assuming gas to hob and gas tap to truma on.

What happens then?
Click to expand...
Ignore where the switches are. That’s just me spinning stuff. I used the van for 4-6 nights on all on and off grid settings. I know what they do. I’m just trying everything to get any kind of light or sound. Currently it’s dead as a do do on any setting
 
Bolti said:
Is it the cig and 12v socket on the dash or hab? side not working
Click to expand...
Cab side. I’ve previously used them charging my phone and worked fine. Now nothing on either and fuses all seem ok in dash. Engine and hab area. BUT I have not used them since having the new stereo fitted so a chance the stereo shop has cocked them up. I doubt it as they are a fantastic shop and don’t do crap work. Bit always a chance. But I have used the heater with the new stereo so that’s not down to them. Only outside chance is they are on the same loop and it’s failed but fuse not obvious
 
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We had a similar problem with our Truma 4e a couple of months ago. No lights showing at all on the control panel (same as yours).

Not sure if you have a Sargent EC500 Power Control System but we put ours into shutdown, went out for an hour or so and powered it back up when we came back and the Truma 4e seemed to have reset itself and worked. It think it had got it's proverbials into a twist as I'd been turning the knobs back and forward quite quickly and possibly "confused" the electronics. Might be worth a try disconnecting the 12v power to the system?

I think the two 12v cab sockets may be on different fuses so probably unlikely to be a fuse problem? Are they ignition switched and do you have the ignition on? I guess you will but .........
 
Gellyneck said:
We had a similar problem with our Truma 4e a couple of months ago. No lights showing at all on the control panel (same as yours).

Not sure if you have a Sargent EC500 Power Control System but we put ours into shutdown, went out for an hour or so and powered it back up when we came back and the Truma 4e seemed to have reset itself and worked. It think it had got it's proverbials into a twist as I'd been turning the knobs back and forward quite quickly and possibly "confused" the electronics. Might be worth a try disconnecting the 12v power to the system?

I think the two 12v cab sockets may be on different fuses so probably unlikely to be a fuse problem? Are they ignition switched and do you have the ignition on? I guess you will but .........
Click to expand...
It’s a good shout.

I just took out the EHU. Pulled the fuse from the leisure battery and dropped all breakers too. Left it a few min then powered back up to no success.

Yes to ignition on. They are dead

There is 100% power to the unit and even the switches as put the multi meter across those too.

I’m running out or have run out of ideas here

I guess there is every chance the unit is dead

It worked fine. Put it in storage for a week. Took it out and not worked. Chance water froze and cracked something inside? It was below zero. I’d depressurised the system and it should auto dump the boiler too.
 

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Have you checked the reset button on the combi? It is a 240v overheat button but may effect other operations.
Are you certain the boiler dump valve is automatic as the Bessacar I used to own had to be drained with the yellow water release valve near the boiler. (but things may have changed)

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Is there a plug to the back of the control unit? Can they be taken off to check?

Could the control panel be set to run of the cab battery, which might also feed the faulty 12v sockets. Could the cab battery be at fault? Could the new radio have drained the cab battery?

just trying to think. Hope you get it sorted for your trip.
 
The reset button would be on the left of your photo (Red button) if you have one.
The black sleeved wiring that goes to the control panel looks as if it has been squashed at some time ,by the cover , could the fault be there?
 
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Cush said:
Is there a plug to the back of the control unit? Can they be taken off to check?

Could the control panel be set to run of the cab battery, which might also feed the faulty 12v sockets. Could the cab battery be at fault? Could the new radio have drained the cab battery?

just trying to think. Hope you get it sorted for your trip.
Click to expand...
Had those off. There are nothing more than a phone line type plug that comes from the Truma unit direct to the controls.

It looks like power into the Truma is from the Leisure battery via the consumer unit. As it’s powered and showing 14.4v on EHU the power is correct.

Nothing else looks to interfere with the system. It’s just not responding to any command. Switches were swapped out at the dealers today and made no difference so original ones put back in.

22ECCCA6-E612-4C7B-952F-BCD71C0BB19C.jpeg


Truma unit goes into the empty socket in the photo then the two switches are joined together by the same style wire. All very simple to be fair
4AF9A34B-D2BC-4715-BE9E-531F7A8B4911.jpeg

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I have even removed the power wires from the board as shown in the photo to de-power it and try a reset. Nothing
 
Have you managed to prove, 100%, that you’re getting 12v power from whichever of those cables is the main supply into the truma unit? I.e tested from the truma end rather than the supply end?

If you can confirm this with your meter then, you know that the issue is from that point onwards (i.e. most likely with the unit itself)

If not, then the power supply (and cables, unknown inline fuses, etc) is still a likely (and simpler/cheaper) culprit.
 
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At the start of this years camping I had no lights, tv , fridge. It was only when turning on the boiler switch that everything started to work. I had the neighbour check everything previous to that, without finding any fault. I would suggest trying to turn on every electrical item in the van.
 
davidathomas42 said:
Had those off. There are nothing more than a phone line type plug that comes from the Truma unit direct to the controls.

It looks like power into the Truma is from the Leisure battery via the consumer unit. As it’s powered and showing 14.4v on EHU the power is correct.

Nothing else looks to interfere with the system. It’s just not responding to any command. Switches were swapped out at the dealers today and made no difference so original ones put back in.

View attachment 570095

Truma unit goes into the empty socket in the photo then the two switches are joined together by the same style wire. All very simple to be fair
View attachment 570096
Click to expand...
You appear to have one cable connecting the two switches but where is the external 12v power connection? I assume something is plugged into the unit which appears to have an empty socket (lower photo, right hand until). Is that where the power enters?
 
If you are getting 12v at the controls (which is supplied from the combi) and you are sure the other very thin wires that connect the controls to the PCU are all ok and you are able to confirm it is a faulty PCU there is one for sale in the Classifieds ,( in case you have not already seen it.)

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JimmE said:
Have you managed to prove, 100%, that you’re getting 12v power from whichever of those cables is the main supply into the truma unit? I.e tested from the truma end rather than the supply end?

If you can confirm this with your meter then, you know that the issue is from that point onwards (i.e. most likely with the unit itself)

If not, then the power supply (and cables, unknown inline fuses, etc) is still a likely (and simpler/cheaper) culprit.
Click to expand...
Yea. The multi meter went into the spade connectors on the unit and showed 14.4 volts on EHU. There is no power across the bridge on the mini 10amp fuse when it’s switched on. Well with the switch in the on position that is.

8EA3F4E1-0977-418D-9215-AA895A1A6705.jpeg
 
GeoffnDee said:
If you are getting 12v at the controls (which is supplied from the combi) and you are sure the other very thin wires that connect the controls to the PCU are all ok and you are able to confirm it is a faulty PCU there is one for sale in the Classifieds ,( in case you have not already seen it.)
Click to expand...
Can you link me that
 
www.motorhomefun.co.uk

Truma combi 4E pcb

Truma Combi 4E printed circuit board perfect working order checked by Truma and in sealed bag with no faults confirmation. Cost new £265 Will accept £179.
www.motorhomefun.co.uk www.motorhomefun.co.uk
 
Sorry can’t be anymore help. Really hope it gets sorted.
 
I had the same problem and it turned out to be one of the switches on the Sargent consumer unit (the fuse board) wasn’t on!
 
davidathomas42 said:
It’s a good shout.

I just took out the EHU. Pulled the fuse from the leisure battery and dropped all breakers too. Left it a few min then powered back up to no success.

Yes to ignition on. They are dead

There is 100% power to the unit and even the switches as put the multi meter across those too.

I’m running out or have run out of ideas here

I guess there is every chance the unit is dead

It worked fine. Put it in storage for a week. Took it out and not worked. Chance water froze and cracked something inside? It was below zero. I’d depressurised the system and it should auto dump the boiler too.
Click to expand...

Guessed you would have had the ignition on!

On the power shutdown I had tried it off for a couple of minutes with no success however after being off for a hour or so it had reset. Might be worth a try?

davidathomas42 said:
Had those off. There are nothing more than a phone line type plug that comes from the Truma unit direct to the controls.

It looks like power into the Truma is from the Leisure battery via the consumer unit. As it’s powered and showing 14.4v on EHU the power is correct.

Nothing else looks to interfere with the system. It’s just not responding to any command. Switches were swapped out at the dealers today and made no difference so original ones put back in.

Truma unit goes into the empty socket in the photo then the two switches are joined together by the same style wire. All very simple to be fair
Click to expand...
When we had our problem I phoned the guy who has done some work on our van before and he said (if memory serves me correctly) there are two RJ45 type sockets on the boiler itself (next to each other) and he said switching the cable to the other as he has seen the socket going faulty (minor corrosion \ dirty?). Before switching over try pulling and reinserting the plug a couple of times as it sometimes "cleans" the connection.
As I didn't get to this point, as ours reset and starting working, I didn't try that so ..........

davidathomas42 said:
Yea. The multi meter went into the spade connectors on the unit and showed 14.4 volts on EHU. There is no power across the bridge on the mini 10amp fuse when it’s switched on. Well with the switch in the on position that is.
Click to expand...
Have you tried replacing the fuse, or at least, checked continuity through it?
 
Gellyneck said:
Have you tried replacing the fuse, or at least, checked continuity through it?
Click to expand...

I’ve checked the fuse and it looks fine. I didn’t try continuity through it though as it’s glass and looked perfect. Maybe still worth trying though as could be blown in the metal end cap I can’t see I guess.

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