Where can I get a replacement duo therm 3105058 thermostat

the same one from the service agent spares

There isn't one. Every a/c unit is a piece of junk. Just like your t.v., fridge, and microwave. Buy cheap, replace when it breaks down. It's all luck, so Good Luck!! Best Wishes!!

If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

Sorry we have no way to look this up for you. Contact a local heating and AC contractor.

didnt specify model number of stat --can notify domestic they make the duo therm products
dometic com

Need to check the wireing for ashort

there is a fuse located under the shroud on the roof AC on a circuit board that controls the thermostat to turn on the power to the Air Conditioner replace it it is marked F-1 or, on some F-2 etc.
the air conditioner works on both DC voltage for the thermostat and AC voltage for the compressor

Can you attach a picture? Does it look like this one?

I was replacing a DUO-Therm 3105058 Rev A. very old Thermostat in a Coachman RV with 3106995.032 from Amazon. After looking all the information on the directions it was clear I would have to play a hit or miss on some of the wiring. Instead of using the same coding, such as RC, RH, G, Yellow and such. they used the function and I had to guess at some.
Here is the wiring I found worked:
There are 6 wires. One set of two wires (white On the W & red on the RH) and the set of 4 (yellow On the Y, green on the G, red on the RC and blue on the H). So to keep it simple the red on the RH went to the +7.5. The White on the W went to the FUR. HS/HP not used. the Yellow from the Y went on the cool. The green on the G went to the fan. The red on RC went to GND. and the Blue on H went to Hi fan.
So red (RH) of the 2 wire goes to +7.5
White (W) of the 2 wire goes to FUR.
Yellow (Y) to cool
Green (G) to fan
Orange or red from the RC lug goes to GND
Blue (H) goes to Hi Fan

a. Remove the cover of the thermostat.
b. Connect the RED wire from the air conditioner
to the “RC” terminal on the thermostat.
c. Connect the “YELLOW” wire from the air conditioner
to the “Y” terminal on the thermostat.
d. Connect the “BLUE” wire from the air conditioner
to the “H” terminal on the thermostat.
e. Connect the “ORANGE” wire from the air conditioner
to the “G” terminal on the thermostat.
f. Push the thermostat wires into hole in wall and
fill excess hole with insulation.
g. Mount thermostat base to the wall with screws
provided.
h. Check all thermostat wires on base to ensure
they are completely clear of the bimetal coil of
the thermostat. Adjust if necessary.
i. Replace thermostat cover.
If nothing operates on the air conditioner, remove the
return air grille assembly and verify the red, orange, yellow
and blue wires are properly connected (red-to-red,
orange-to-orange, etc.).
Next, disconnect the red wires and check for 12 volt
DC between the red wire from roof section and the orange
or blue wire from roof section. If no voltage received,
refer to Section F2. If voltage is received, the
problem lies with the thermostat or thermostat wires.
Next, disconnect all 4 wires (red, orange, yellow and
blue) from the thermostat. With the thermostat set on
COOL mode, FAN mode set on AUTO and HIGH, and
temperature selector set lower than the room temperature. Check for continuity between terminal RC (red wire)
and terminal G (orange wire); and RC (red wire) and
terminal H (blue wire). If continuity is achieved on each,
proceed with the next step.
Set fan switch to LOW. Continuity should NOT be present
between terminal RC and Terminal H, but present between
the other terminals (Y & G) and terminal RC.
If all of the previous checks are good, the thermostat is
good, do not replace it. If any one of the previous checks
are not correct, replace the thermostat.

red and white are positive and neg 12v
green is low fan
grey is high fan
yellow is cooling
blue is neg 12v(marked B-)