How to tell if fridge on electric is working easily?

[Anders79]

The only way i know to tell if the fridge is working when on electricity is to wait for an hour and see if the temp starts to decrease. Is there anything easier and faster. I have lately had instances where there is no flashing on the display it says it is on electric but didn't cool down until cycling on/off

[GetawA-S]

You are trying to measure what you cannot see. Time to call Metrology Man! (Or Metrology Mama, depending on who is staffing that shop on a particular day)
If he’s busy, get yourself a power protection device with a watt or amp indication. (Hughs Power Watchdog works for me.) The heater on your absorption fridge pulls about 150 W, or about 1 1/2 A.
When you turn on your fridge, your trailer’s instantaneous usage should immediately jump by that amount.
O, if you don’t trust your calibrated fingertips, get a non contact thermometer and point it at the fins five minutes after starting up. (About $30 at Harbor Freight, and good for more uses than you could imagine!)
Fins not any cooler than the rest of the fridge? Cycle the power and try again, or whatever works for your particular incarnation of the Dometic Demon.
Good luck!