Rear left Tail light , front left parking light both turn off

I have a 2004 Audi A4 , having an issue with the rear driverside tail light going out after about 10 minutes of driving with the lights on. Also the fron driverside parking light goes out , just a few seconds after the tail light. Warning lamps chime in the dash , then turns into a picture of a light bulb with an X through it. We have replaced the bulbs , as well as a module. Neither of those worked.... help , this is getting expensive.. ! If I turn the lights off then on again they will work for a few more minutes until the do it again.. Then I have to repeat.... What a good way to get pulled over huh?.. We have already spent $1,000 dollars trying to fix this. And the Audi dealership doesn't know what to do.