Dometic RMS8401 fridge dead. Control panel?

[terrymac]

We have a Dometic RMS8401 fridge, 4 years old, never given a problem. Last used about a month ago. Tried to turn it on a few days ago and the control panel on the front is dead, the fridge just won't turn on. Fridge interior light not coming on.

The permanent feed at the back of the fridge from the leisure battery is fine, the feed from the alternator is fine when the engine is running. The only unusual event I can think of is that we had 3 successive days of hard frost last week.

I've downloaded the Dometic service manual which doesn't quite match our fridge, it shows a 1A fuse on the PCB behind the control panel but there is no fuse on ours. The only connections to the control panel are a ribbon cable and a thin twin-wire lead. The control panel is the manual-switching automatic ignition one with the squidgy buttons.

I've tried disconnecting the permanent feed from the leisure battery and leaving it disconnected for half an hour in the hopes it may reset the control panel but to no avail.
I can order a new control panel part #2890638-02 and the panel appears easy to swap out but I'm just wondering of there is any other troubleshooting I can do first. And if anyone has actually replaced the control panel did they have any issues I should be aware of?

Thanks in advance.

 

[GeoffnDee]

The control panel is linked to the control module (P860) that is on the rear of the fridge by the ribbon cable and it could be worth checking the connections of the ribbon cable
The module shown , in some manuals , with a 1amp fuse and fitted behind the front panel is fitted to the earlier 8 series control system (pre MES4-C1 type control panel )

 

[Diabalo]

I replaced mine with no problems using the existing ribbon cable.

 

[terrymac]

The control panel is linked to the control module (P860) that is on the rear of the fridge by the ribbon cable and it could be worth checking the connections of the ribbon cable

Thanks. I’ll have a proper look when the weather calms down. The cable is definitely firmly attached to the control panel and the other end does go that control module but after all the horrendous potholes on Skye recently it could have slightly disconnected.

 

[terrymac]

I replaced mine with no problems using the existing ribbon cable.

Thanks.

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[GeoffnDee]

When you are checking the ribbon cable connections , the 12v electronics supply input connection into the P860 would also be worth checking for corrosion or damage(3 x pin connector at the bottom on the right hand side )

 

[terrymac]

When you are checking the ribbon cable connections , the 12v electronics supply input connection into the P860 would also be worth checking for corrosion or damage(3 x pin connector at the bottom on the right hand side )

Thanks

 

[WASPES]

I had to buy one for my fridge last year cheapest price I found was amazon

 

[terrymac]

Quick update:
Firstly thanks for all the very helpful replies. Even my small hands can't get to the P-860 unit to prise the covers off the 12V IN and the ribbon connectors to check but everything in that area is spotlessly clean and no sign of any corrosion so I'm going to order the control panel as that's the easiest fix. If it turns out to be the P-860 box instead then that will be a fridge out job.

 

[TheBig1]

Do you have a multimeter? would speed up fault finding. If you are local to Bournemouth somebody is selling a dometic control panel on facebook

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[TheBig1]

 

[terrymac]

View attachment 825784

Yes got a multimeter thanks. Thanks also for the heads up on the panel for sale but we’re in Cumbria and looking at the pic it looks like it could be the straight panel, ours is the curved panel. Ordered one from Leisure Warehouse, should be here in a couple of days.

 

[two]

I think the panels are sensitive to (electrical) spikes.
If it happens again, I'd suggest that the panel failure is being caused by something else in the van and that could be difficult to trace (especially if it's an intermittent fault).
Good luck!

 

[Hymerboy]

The fridge works off the engine battery not the liesure one, I had to replace the front panel, the engineer wanted to take the fridge out but I told him to just undo the conector from the rear pcb and tie a line to it and then pull it out from the front panel so you can reverse the procedure with the new one, simples.

 

[terrymac]

I think the panels are sensitive to (electrical) spikes.
If it happens again, I'd suggest that the panel failure is being caused by something else in the van and that could be difficult to trace (especially if it's an intermittent fault).
Good luck!

sorry for delayed reply - an electrical spike makes sense but that would have had to happen somehow whilst the van was completely shut down for about 4 weeks. Now fixed cheers

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[terrymac]

The fridge works off the engine battery not the liesure one, I had to replace the front panel, the engineer wanted to take the fridge out but I told him to just undo the conector from the rear pcb and tie a line to it and then pull it out from the front panel so you can reverse the procedure with the new one, simples.

Thanks for taking the time to reply. The control panel is permanently powered from a feed off the leisure battery, presumably so that the fridge can be managed whether engine is running or not or on EHU or not etc. Of course the actual cooling functions are powered by gas, EHU or the power feed from the alternator when the engine is running as you say.

 

[terrymac]

Update: replacement panel arrived today. Managed to re-use the existing ribbon cable and the cable to the gas burner temperature probe - it took two us to very carefully flex the "wedges" on the plastic panel to release the cables supplied with the new panel and then connect the new one up. As soon as I reconnected the permanent feed from the leisure battery the control panel started beeping because it was last run off the alternator. Selected gas and off it went. Just starting raining again so I'll test it on EHU when the rain stops and test it off the alternator later but hopefully all ok now.

Thanks again for everyone's help.

 

[two]

Great that you're back, up and running again.
If it happens again, you have merely practised removal of the effect.
I fear that the cause may still need to be tracked down.
Best of luck!

 

[terrymac]

Great that you're back, up and running again.
If it happens again, you have merely practised removal of the effect.
I fear that the cause may still need to be tracked down.
Best of luck!

Cheers. If it happens again I'll likely send one of the control panels off to ApulJack Electronics to see if they can repair it, I'd never heard of them until I started Googling after we hit this fault. There seems to be a few places selling the panels so guessing they don't last too long, the failed panel has a 2018 sticker on it and the fridge was fitted summer 2019, the replacement has a 2022 sticker on it.

Thinking about spikes though I think in future just in case we will make sure to power the fridge off before turning engine back on after refuelling or before connecting EHU, I would have expected the fused supplies to take care of spikes but can't think of anything that could have fried the panel.