rear parking lights go out on long trips

Do you have a multimeter to do some testing?

yes

So are you only loosing the front parking lights or all the parking lights?

only loosing the rear parking light

Behind center of the dash is your lighting control module when the lights are inop you will have to check your input and output in the lighting control module.The white wire with a black stripe should have a ground input of 2 ohms or less with the parking lights on.Then the brown wire should be a battery voltage output with the parking lights on.Let me know what you find.

ok thank you i will let you know

Your welcome keep me posted.