Is the truck a 2019 Limited LTD (2014-2019 old body style) or 2019-2024 new body style?
VIN # will be required to identify RPOs below.
2019 (New Model) has two Regular Production Option (RPO) codes AED or AEF for power windows. The passenger door switch (S79P) functions completely differently for each RPO.
Scan the system first and look for associated codes set in the BCM.
RPO AED. The S79P switch simply reverses power and ground at switch terminals 9 (GN/GY) ckt 3387 & 10 (YE/BU)ckt 3388.
RPO AEF. For UP, the S79P switch provides a ground path input to the M74P window motor at pin 11 of the switch ckt 3384 (YE/BK) to the UP circuit.
Note: AEF - Each press of the switch for UP, DN and Express only provides a ground path, compared to RPO AED.
B+ is supplied directly to the window motor.
The S146 driver's switch connects directly to the M74P window motor on ckt 6134 (GN/YE) Lin Bus 3 in both RPO AED and AEF.
