Looking for the halogen diagram but can’t find it. Trying to convert my 2012 halogen headlights to 2015 halogen Lexus headlights. Everything works on the new headlight except DRL and Parking. Thanks in advance!

 

If you join the Toyota Technical Information System (TIS) database for a couple of days for $30 you can access the wiring diagrams and full service manual
https://techinfo.toyota.com/techInfo...a.com%3A443%2F

 

Not sure if this applies, but the older version [I am not sure when Lexus RX made the switch] the DRL used to be filament high beam and hooked top in series [with relays] to produce lower light as each bulb gets 6v.

You are on the right track to investigate. Let us know what you find out.

Salim