Hate to say it but the switch likely wasn't the problem. Those lights are not actually switched by it, they are switched by the body control module. The dimmer switch just tells the BCM to switch the beams by grounding a signal pin. To determine if the problem is in the BCM you will need to access pin 7 in the C1 connector on the BCM. It has a Black wire with a white stripe. That is the wire that the BCM grounds to activate the high beam relay.
To test it you just need a simple test light that is connected to a good ground.
To get to it remove the trim panel on the left end of the dash, look in there and you will see an electrical connector on the top of the BCM. Next go under the dash and remove the push pins holding the insulator cover over the foot well on the drivers side Pic 3.
Now use a trim stick to remove the trim ring around the ignition switch then remove the center stack trim panel Pic4. Next you remove the screws and pins for the trim panel under the steering column Pic5. Now you can look up in and see the connectors on the bottom of the BCM.
The connector you need has 50 pins in it and will have 5 orange wires in it with 3 of them right next to each other. I cannot remember if that is the side connector you can see from the side cover or the bottom large connector. But if you look for all the orange wires that is the one. Now look for the Black wire with white stripe. It will be pin 7 and between a solid black wire and a Dark Green wire with white stripe.
The test is simple, take the grounded test light and with the key on touch it to that wire. If the high beams come on all of the rest of the high beam parts are good. But you are not getting the control signal from the BCM. The solution is to replace and reprogram the BCM.
For that you need a dealer scan tool and access unfortunately. Because the dash indicator comes on for high beam we know the switch is working and the BCM is getting the signal to select high beam, it just isn't doing it.
Images (Click to enlarge)
Wednesday, December 9th, 2020 AT 8:39 AM