My friend has the same problem. i guess its just a regular problem and might not even be from the way its wired. just the product itself.

 

I would be interested to hear if pressing on the gas (while the car is running) and then turning on the lights helps in getting both of them on at once...if it does help, then you know the bulbs weren't getting enough juice to turn on and you know the temporary solution is to press on the gas as you are turning on the lights haha