I have a Chevy uplander 2007, the front passenger turn signal won't work if the lights or parking lights are on but if the lights are off the turn signal works

 

How long have you owned the vehicle?
I find that my 2007 Uplander needed new front bulbs about every 3 yrs or so.
If your bulbs haven't been changed lately I would start there.

 

while you in there checking the bulb, check for power at the connector. Its a 2 filament bulb.
the brown wire feeds battery voltage to the park lights, the blue/white wire should have battery voltage for the turn signal.

 

I've owned it for 5yrs

I've had to replace the bulb every 6months it seems