DRL inhibit modification for Freightliner chassis

[dpinvidic]

I searched a lot of posts regarding the inability to Flash your headlights while driving. Some mentioned a "UNUSED PIN" on the lighting control module.

This post describes the simple modification I did on my 2014 XL chassis.
The lights are controlled by a "Lighting Control Module"(LCM), which has two large connectors on it (16-pin & 10-pin).
One input to this unit is the parking brake switch (Grounded when parking brake is applied).

The LCM turns on the low beam headlamps at full power when driving in the daytime. The high beam switch has no affect if the headlamp switch is off.
I simply added a momentary switch in parallel with the parking brake switch in order to make the LCM think that we are parked.

The only negative thing about this is that the Parking brake alarm sounds when I flash the headlamps with my new switch.

This can easily be fixed by using a SPDT switch instead of a SPST switch and interrupting the connection between the LCM and LBU (Light Bar Control Unit) which controls the parking brake alarm. I have not made up my mind if I like the reminder that the DRLs are being flashed.

Below is the freightliner schematic, and a picture of the LCM after the modification. The R/W wire is the parking brake wire.

Regards,

Dan

[britcon]

I assumed the Phaeton came with the " Smart Wheel " which has light flash buttons built-in. Guess not ?

[dpinvidic]

Originally Posted by britcon

I assumed the Phaeton came with the " Smart Wheel " which has light flash buttons built-in. Guess not ?

Not on this model. I just don't understand why Freightliner did not build the LCM give us a way to do it with the headlight switch.

Dan