Transmission/running lights

I have a 2001 gmc yucon and recently had the transmission flushed. Now the driver side running lights don’t activate when the car goes in gear but the passenger side does. Could this be caused by the transmission flush or is it just a coincedence that it happened at the same time?

Check the high beam on the driver’s side. My 200 Blazer uses the high beams at reduced brightness for the DRLs.

Ed B.