I know that this has kinda been covered before, but here goes.

Ive got el heater controls etc in the lane. Now the problem is, it only works on high. Ive checked the plug that goes into the heater box, and im getting power there (12 volts at all wires when fan speed is on any speed) except when in the off position. Pulled out the controller, and it doesnt appear to be burnt out etc. Also, there appears to be a provision for a second plug. There is the one with about 5 wires from memory, but also another spade type terminal, which hasnt got anything plugged into it. Should this have something connected to it, and if so, to what. Any help with this would be great. Cheers.