I've gotten many replies on things to look at/for. Thanks to all of you for your help.
Bought a controller and strip here a few months ago and they worked then. The other night, the strip would not put out any heat. The LED in the controller was lit. Is there any way to tell what might be wrong? Do the heater strips just stop working after awhile and need to be replaced?
I tried running it off a deep-cycle battery and a power supply so lack of proper power is not the problem. Your suggestions are appreciated.