Fridge Electric Lamp But N0 120v

Dometic refers, there is NO indication if the 120 side has FAILED to operate other than NO Cooling. IF you lose 120 volts, then the unit will switch to LP if you have an AUTO switch Dometic. I have never seen your model Servel, most USA built RV's the Servel line was dropped as a name in the late 70's early 80's after Dometic purchased them. Most older RV refers, the inside eyebrow lite would NOT show 120 unless the 120 operation was selected. From your post, I believe you stated, the refer SHOWED 120 selected and the light was ON, but you did NOT have 120 to the refer and it failed to cool. Which is a normal fault on a Dometic brand. Yes, adding a small 120 light to let you know you indeed have 120 to the back of the refer is a good idea. Norcolds, starting back in the 90's incorporate a logic in the control board to let you know if you have 120 selected and the unit fails to have 120 supplied to the refer and if you have the model with that feature will have a fault and beep. Doug