Dometic RM 1272 wiring diagram anyone?

[mikep51]

I am restoring a 2000 Fleetwood Discovery 37V. Most recent is replacing the cooling unit on a Dometic RM 1272. After replacment the unit will not power up. I am getting over 12.5 V to the board, Gas is hooked up and 110 is hot. Checked the fuses on the board and they are good. Board is OEM.

The wiring diagram has been destroyed on this unit. Can anyone point to where I can find it? Anyone have this unit and can send me a photo of the schematic that is on the cover plate over the heating unit?

Any troubleshooting tips would be appreciated.

[BFlinn181]

Here's the operating manual, it has a wiring diagram on the last page.

This Google search also yielded a bunch of wiring diagrams, but some are not for your unit, I'm sure.

[homerbw]

I did the same thing you are doing on my Dometic and spent about $1,300 on parts not including labor (free because I did it myself). If I had to do over, I would have purchased a residential and installed it.

[MSHappyCampers]

Hi ! Welcome to IRV2! We're sure glad you joined the gang!

Have you checked with Fleetwood tech support? Keep her between the ditches!

Good luck, happy trails, and God bless!

[Gary RVRoamer]

This Dometic 12-series Service Tips document should tell you all yu need to know.
http://bryantrv.com/docs2/docs/1252service.pdf

If the front display "eyebrow panel" doesn't light up and you have 12v power to the main board, odds are its either the wiring harness to the panel or the upper circuit board. If the panel lights up and shows status, but no cooling,, more likely the lower board. 120v does nothing except power the heater when in AC mode, so isn't really relevant. If gas mode works but AC does not, start looking at the electric heater circuit.

[Old-Biscuit]

In outside compartment next to lower control board should be a DC Terminal Block
12V DC POS & NEG from battery ----------POS thru a FUSED circuit in DC Dist Panel

DC from Terminal Block goes to lower control board.........
POS to J4 position then to the 3A Fuse on control board
NEG to GROUND ---------J7 position on control board also goes to ground

Always TEST a fuse (vs visually looking at it).....both sides and contacts

[mikep51]

Thanks for all the help.

I am still chasing the issue, I have verified there is DC voltage going into the control board and no power going to the eyebrow. Fuses are good, voltage is good (both A/C and DC). I am about ready to replace this board, but in tracing all the wires I find one component I cannot account for.

Glued to the outside cover of the control board is a small component with three wires, RED, BLUE and Black. One is hot coming in, one is a ground and there is nothing coming out of the third wire. Anyone have an idea of what the function of this is and if I need to be concerned?

[mikep51]

I found a great resource at Dinosaur Electronics, in a Tech named Joe. He was extremely patient, even when it became evident he was not going to sell me anything.

We worked thru the issue and it turns out to be a thermal cutoff that is mounted on the heating stack (pic attached). After Jumping around this switch, everything started working.

Camping World gave me a Dometic part number of 2930463019, although I am not completely confident they found the right part.

[mikep51]

Picture failed to attach to previous message.

[BFlinn181]

Glad you got it figured out and reported back to help others! Safe travels!

[Old-Biscuit]

That THERMAL Switch is a Safety Feature.........HIGH TEMP TRIP SWITCH

Are you SURE switch is BAD
OR
Is it tripping due to high temp being sensed????????????

When tripped (>350*F) it shuts down DC to control board to PREVENT overheating/cooking of the 'perk tube' (boiler section)
Overheating is due to LACK OF COOLANT FLOW......blocked/obstructed cooling unit


Temp switch can fail..........but majority of time it is REAL and cooing unit is bad

With switch bypassed IS fridge cooling down?

Any signs of 'yellowish residue' around/in burner area?-----(leak from cooling unit)

That Dometic part number (2930463019) is for the DC Terminal Block....not the thermal fuse/high temp switch
Dometic does NOT provide a part number for that switch.....they are NOT available retail

If cooling unit actually is properly cooling down/functioning with switch bypassed (bad switch????) then find a Dometic Authorized Repair Shop/Mobile Tech etc and see if they have an "extra" switch from a 'Recall Kit'----
Good Luck with that


As for that 'box' on cover of control module---that would be the 'reigniter'---opens solenoid valve while electrode is firing

[mikep51]

Thanks for the explanation. I am confident the switch is bad. Cooling unit is new (Amish built unit) and had never started up when this was discovered. This switch was not allowing current thru it when I tried to start the unit, therefore not allowing it to start for the first time, there is no way it was tripping from overheat. When I inserted a jumper, the unit started up on 110V and when I unplugged that, the Propane lit.

Flame on the burner is a nice blue color, no residue seen. Unit cools down nicely. I ran it for about 3 hours to check and it is shut off until I get a new switch.

After posting the note, I did discover that Camping World gave the wrong part number, so the plan is what you suggested. I will pull it out and work on getting a match.

I appreciate the help and especially the safety concerns.

[mikep51]

Thanks for the explanation. I am confident the switch is bad. Cooling unit is new (Amish built unit) and had never started up when this was discovered. This switch was not allowing current thru it when I tried to start the unit, therefore not allowing it to start for the first time, there is no way it was tripping from overheat. When I inserted a jumper, the unit started up on 110V and when I unplugged that, the Propane lit.

Flame on the burner is a nice blue color, no residue seen. Unit cools down nicely. I ran it for about 3 hours to check and it is shut off until I get a new switch.

After posting the note, I did discover that Camping World gave the wrong part number, so the plan is what you suggested. I will pull it out and work on getting a match.

I appreciate the help and especially the safety concerns.

[Old-Biscuit]

Amish rebuilt cooling unit..........
Then it came with that High Temp switch installed so check with the 'supplier' of cooling unit for a new/replacement switch

Dometic doesn't supply a 'replacement'....don't even have a part number for them

Dometic switch is manually resettable.....has a reset button in middle of switch between spade terminals.

Does yours?