Truma trauma - heating off

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I was mistaken on a couple of counts. The 20A EBL 29 fuse only covers the heater. The adjacent 25A fuse covers the step. Both are OK.

There’s 14V at the spade connector going into Truma, presumably from the EBL. The 12V fuse covering the 12V Truma circuits was blown, and is now replaced. There’s still no lights on the display, so no error codes displayed, in fact no signs of life at all.
 
Do you have a Truma CP plus panel? Has the data cable become disconnected from the back of the CP or from the boiler?
 
I have the analogue panels. Nothing is obviously disconnected at the boiler end. I haven’t tried to take the controller off the wall. I cannot imagine a plug, or spade connectors, just falling out.

The thermostat sensor seems to work. At least there’s voltage at the sensor and the heater, and the voltage changes with temperature.

Maybe the fan has given up, but I don’t see why that would stop power getting to the wall controller.

Probably something obvious I’m just missing, but with the help here I’ve already learned a lot, so thanks again.
 
Update: I took the van to Gem Caravans near Dunfermline. They say that there are two blown diodes on the PCB, and have sent the board back to Truma for repair/replacement. I'm expecting this to take a week or two. The underlying, currently unanswered, question is why did the diodes pop? A repaired/replacement board will go bang again if the root cause lies elsewhere.
 
Great to know you're making progress.
I'd wait for feedback from Truma.

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The two diodes might have been from an iffy batch of components. I've just had to have eight replaced on my Denon sound bar, but they were under specced which lead to their failure. At least if they replace the diodes, it should be cheaper than a new circuit board ?
 
Truma heaters do appear to be troublesome over the last few years.

I wonder if the quality has gone down or the sensor/protection circuits are just to sensitive.
 
jockaneezer said:
The two diodes might have been from an iffy batch of components. I've just had to have eight replaced on my Denon sound bar, but they were under specced which lead to their failure. At least if they replace the diodes, it should be cheaper than a new circuit board ?
Click to expand...

Funnily enough my Denon amp has just stopped amplifying the sound. Maybe I should go scouting for diodes there too!
 
Finally fixed. Dougie Wilson from Gem Caravans in Dunfermline sent the PCB off to Truma. They pronounced it to be dead, for £75. Very clever - I told 'em it was dead. New one sourced and installed by Dougie, £324 all told, and we now have heating again.

Maybe a wee outing later this week to check all is well.
 
When I found this post I could not believe how similar it was to my current situation. Right down to taking my MH to Gem Caravans.

Like you I have a Truma Combi6E.
When using the MH, it suddenly just stopped while we were on 240V EHU.
So I went through the checks that I could, like checking all the fuses, resetting the wee button at the heater.
I also used a meter on the 12V terminals and it checked out OK.

Thinking that this is far as I can go with my limited skills, I finally decided to get a designated Truma Service center.
So like you I picked GEM Caravans near Dunfermline, and this is where the similarity in our stories end.

After checking him out on the phone that he was indeed a Truma Service Center, and that he had all the gear to do a full diagnosis, he initially gave me reassurance that he was the guy to go for as he suggested to try a few things, like remove the wee looped wire on the PCB and put it on again.
But still no luck.

When I finally got my van to him, it turns out he did not have any of the diagnosing kit he said he did. In fact he checked nothing and immediately started to remove the PCB. When I questioned this and asked, 'But you said you were going to give me a diagnosis' . His reply to that was to go get a 12V leisure battery to test see if the leds on the rotary switch or the PCB leds came on. They were dead and he could not get a 12V meter reading. When I mentioned that I found this to be strange as I had just checked it with my meter where I had the full 12V, I suggested I check the fuse at the Elektroblock. He got quite annoyed even raising his voice at me, but sensing this I carried on, and sure enough the fuse had blown. Most likely due to what he was doing and possibly deliberate. I put in a new fuse and suddenly he got a reading. He then says to remove the fuse as it is important to do so. So why did he not ask me to remove the fuse earlier?

I got another telling off for suggesting I double check that I removed the fuse. 'I did tell you to do that' he snaps. But I already knew that I did. You would think I was his apprentice or something.

So he carried on removing the PCB, saying that he will send it to Truma. But unlike you, he told me it is a free diagnosing service. He said it would take two weeks. I contacted Truma to confirm this and they did. So why did you have to pay £75? He did mention to me that he had another customer having the same problem at the same time, and that ties in with the timing that you were there.

Returning home though, without the PCB, and thinking of Dougie's contradictory nonsense, I started to 'smell a rat'. So I immediately drove the 25 miles back in my car to get my PCB.

He was not too please when I told him that I would send the PCB to Truma myself (even though he suggested that as an option). In fact he was all over the shop with his 'ducking and diving' antics and quite frankly, bullsh*t. He said that I might as well just pay the £300 now as 9/10 times, my symptoms are caused by a faulty PCB. He insisted I paid him for his service, and in his wee hut where he took me, the first thing he did was clutch the PCB in his hand and did not give it back until I paid him £45.

I could not help but think that, well due to the things he said and the way he said it, I have 'dodged a bullet'.

I sent it to a guy on EBAY who diagnose for £50 and fix for another £100. He found nothing wrong with it and asked that I send the rotary switches and the data cables if I could, but I could only give him the short one. They all checked out OK too. So he says to plug the power source switch into the short cable and directly into the PCB without anything else other than the 12V feed. SUCCESS!

I plugged in the long data cable again and it was dead. So it was the long data cable all along.

So it seems that, not only did Dougie at Gem caravans try to con me of £300, he also wasted four weeks of my time.

Now all I have to do is try to remove and fit the new long data cable and refit my fully working PCB.

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Last edited:
Hmmm! I did think about asking for the old PCB back. He said that Truma would chuck it in the bin.

Mine’s working OK now, but I’m none the wiser about the root cause.
 
[/QUOTE]
I sent it to a guy on EBAY who diagnose for £50 and fix for another £100. He found nothing wrong with it and asked that I send the rotary switches and the data cables if I could, but I could only give him the short one. They all checked out OK too. So he says to plug the power source switch into the short cable and directly into the PCB without anything else other than the 12V feed. SUCCESS!

I plugged in the long data cable again and it was dead. So it was the long data cable all along.

So it seems that, not only did Dougie at Gem caravans try to con me of £300, he also wasted four weeks of my time.

Now all I have to do is try to remove and fit the new long data cable and refit my fully working PCB.[/QUOTE]

I had a similar problem with my 6e about 4 yrs ago, I had a mobile guy who came to my home to look at it , he did a few tests as well as speaking to Truma on the phone and the diagnosis was the same as yours the long data cable . I ordered one myself and routed it my self then let the mobile guy came back and connect and check all was ok
 
I just found the guy to be too contradictory in the things he said. He was a bit nervous too when I went back for the PCB.
He apologised to me for saying he had 'all the gear' when he in fact had nothing at all, but that was the main reason I chose him.

Another thing he did was 'bad mouth' some other local guys that fixed motorhomes that I was not too impressed with.

I just did not like the guy at all. But that is just my opinion.
 

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