Here in the UK caravan fridges are wired up to work on gas, mains electricity and 12v. The 12v electric heater rated is typically around 90 to 100 watts, and is normally only activated whilst connected to a running vehicle ie using a regulated power supply from the car alternator, thus keeping a previously cooled fridge cool whilst travelling. For long journeys this can be important, particularly when liquid refreshment is required to recover from the journey!
I need to know how I can ascertain that the electric heater on my relatively old fridge is actually working ie that the element is intact (modern ones incorporate such a facility!) whilst towing with the car.
I envisage some circuit which will sense current flowing in the wire to the heater and enable an led to light up when doing so, this to be remotely placed somewhere convenient within the caravan.
I have very little electronic expertise and would welcome guidance from anyone who can help.