I “THINK” my refrigerator fan issue has been fixed!!

My Dometic RM8501 refrigerator comes equipped with a small12v fan at the lower left of the unit. It blows upward across the fins to cool them. It is operated by athermoswitch located on the main tube in the upper right.

  I have been trying toadd an auxiliary fan in the upper section to help remove the accumulated hot airand increase refrigerator efficiency. After wiring in the second fan,every timethey ( both original and newly installed) came on, the refrigerator would turnoff and the alarm light would turn on.

 I went through about a week testing every potentialcombination of fans, thermoswitches, 12v terminal blocks,ec. I was plugged in to shore power at my shop. I postedhere and got some good ideas. I watched YouTube videos, I called friends withRV’s, I talked to Dometic Tech people 3 times and was going crazy.

 I could never make the existing wiring work if adding an additionalauxiliary fan in the upper rear refrigerator compartment.

 The wiring was different from 2 other friend’s Rpod 179’s,but they were newer and different from each other actually.  In my case, the two wires(red/black) came frominside the polyswitch--no visible connection available , could only cut and splice new wires.  The red wire came from the poly switchinterior to the thermoswitch-then continued to the fan. The black wire camefrom the interior of the poly switch and went straight to the fan.  That seems to be straight forward. It “SHOULD”work to just cut an existing wire and splice in a new wire. But it doesn’t!

 Maybe that was too much voltage when they came on? Nope,according to Dometic the original fan is .46 amps and the new fan is .32.  I also checked the shunt and when the fanscame on, it showed a .8amp drain.

 Ultimately, the Dometic tech people sent me several webaddresses for service and technical manuals. I found a wiring diagram thatshowed the fans were directly wired from the 12 v terminal block on the back ofthe refrigerator unit and NOT through the polyswitch. I simply capped off the originalred/black wires from the polyswitch and rewired it per the drawing.  I added a red and black from the +/- terminalblock–red to the thermoswitch input and black to the fans. Add a red wire fromthe thermoswitch output to the fans that are wired together. Now, when thethermoswitch closes, all of the fans come on together and the refrigeratorcontinues to cool.

 I’ve tried it most of the day with both propane and shorepower and so far, everything works as expected.

Finally.

  Travel safe and often

Vann

I am having a perplexing electrical issue on my 179.

 I am trying to add an additional auxiliary fan in the top ofthe rear refrigerator compartment to help exhaust hot air. The new fan is asmall 4” computer 12vDC fan rated at .32amps. I spliced into the existing black/red wires that go to the original,factory installed fan located at the bottom of the compartment. Every time thefans come on, the refrigerator dies and the red alert light comes on almostinstantly. But both fans continue to operate. So, the 12v power to the fans continueseven though the refrigerator stops.

 The existing fan works fine, the thermoswitch sems to workfine and everything is good until I add the new fan—then the refrigeratorstops.  I am plugged in to shore power.

 Other people have added auxiliary fans without issues-whatis the problem here? Any ideas why the new fan kills the refrigerator?

 Thanks for your help and ideas

 Vann

Travel safe and often