Was the light ever working? You need 3 connections to the lighted switch. You have the hot wire to the switch, you have the wire from the switch to the relay that turns on the 120v heating element, and you have the ground wire that is only required so the switch will light up.
If the heating element is working, then wires 1 and 2 are working. The only other possibility is the ground wire is not grounding.
(Once the switch lights up, if it is lit up ALL THE TIME, you have wires 1 and 2 reversed.)
Bobbo and Lin
2017 F-150 XLT 4x4 SuperCab w/Max Tow Package 3.5l EcoBoost V6
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