Fridge: dometic a.e.s. (auto energy select)
What it is
A.E.S. fridges pick the energy source themselves. Priority: 1) 120 VAC, 2) 12 VDC heating element (only when the ignition key is on and the vehicle is in motion), 3) LP gas. Models: 1st gen RM663, RM763, RM1303; 2nd gen RM3500, RM3600, RM3800; plus a later 3rd generation.
A 12V DC hookup to the terminal block is required for the fridge to run on ANY mode, including 120V and gas. No 12V = no fridge.
Parts (rear, through the lower vent)
LP shut-off valve and knob, 12V terminal block, LP solenoid valve with a 12 mm test plug for checking gas pressure, orifice/burner, 12V and 120V heating elements in the boiler above the burner, printed circuit board, 12V DC relay that powers the DC element, and an igniter/re-igniter module (replaces the piezo). If the flame blows out the igniter relights it.
The LED
SOLID GREEN|On, enough 12V|Normal.
FLASHING RED|Gas failure|No flame in about 3 minutes on LP. Usually out of LP, dirty burner or air in the line. Reset: main switch off, wait about 5 seconds, back on (another 3 minute try).
NO LIGHT (switch on)|Low voltage|12V at the terminal block dropped to about 9.5 VDC. See below.
Low battery protection
At about 9.5 VDC at the terminal block, if it was on 120V or LP, the board bypasses the thermostat and runs continuously on LP until voltage recovers. The LED goes out as the warning. On the 12V element mode the DC relay cuts the element when voltage is low, and the LP flame will not light during the low voltage.
Ignition-lock terminal (12V mode)
12V element mode depends on correct field wiring of the ignition-lock terminal on the back of the fridge. Key on: flame shuts off and the DC element runs. Key off (fuel stop): the burner is held off for about 25 minutes, then relights on LP if no ignition and no 120V. The 120V mode is NOT affected by the delay.
No 12V mode while driving: check the ignition-lock wire for 12V with the key on.
Fridge relights on gas at the fuel pump right away: the 25 minute delay isn't working; check that same ignition wire.
On LP the A.E.S. has no high/low flame. The flame shuts off completely when the thermostat is satisfied and relights when it calls again. Normal 1st gen thermostat setting is 4 (about 35-40°F in the lower cabinet).
DOMETIC|Dometic A.E.S. Diagnostic Service Manual (via myrvworks.com, OCR)
Keep going on refrigerators
Learn it
- Absorption fridges (gas/electric)
- 12V compressor and residential fridges
- Absorption fridge won't run on gas
- Absorption fridge won't run on electric
- Is it the cooling unit?
Prove it
- Fridge won't run on gas
- Fridge is warm after unplugging
- Fridge works on gas, not electric
- Fridge won't cool on anything
- Freezer's fine, fridge is warm