Steve Boylan first here is how they operate.
Low Beam Operation
With the lighting switch in 2ND position, the BCM receives input requesting the headlamps to illuminate. This
input is communicated to the IPDM E/R across the CAN communication lines. The CPU of the IPDM E/R controls
the headlamp low relay coil. When energized, this relay directs power
- through 15A fuse (No. 36, located in the IPDM E/R)
- through IPDM E/R terminal 20
- to headlamp RH terminal 1, and
- through 15A fuse (No. 45, located in the IPDM E/R)
- through IPDM E/R terminal 30
- to headlamp LH terminal 1.
- Ground is supplied
- to headlamp RH terminal 2
- to headlamp LH terminal 2
- through grounds E15 and E24.
With power and ground supplied, low beam headlamps illuminate.
“I checked the 2 fuses under the hood, I bought a new headlight switch on the steering column and replaced that “, but you did not say you checked the relay. That is where I would start.