Windjammer Tank Heater Switch - No light

[cobiker]

Not quite ready to winterize the trailer, and the temps are supposed to drop to 20 degrees tonight. So the furnace is on but when I turn the switch on for the tank heater, it doesn't light up like the water pump and water heater switches do. Checked breakers and fuses and all looks good.

How can I tell if the tank heaters are on?

Thanks,
Scott

[boatsNtrees]

Pull the panel and look at the switch. A multimeter will confirm voltage across the contacts.
Compare the tank heater switch with the lighted water pump switch; if the tank heater switch has two wires, the water pump three, it's because the tank heater switch does not have a light.

[wrvond]

It's possible the tank heaters are thermostatically controlled and do not come on until the temp drops to freezing. Waiting for that to happen could put you in a bad position if they really aren't working, though.