I installed switchback bilbs in my '17 non led truck yesterday and I tested them before putting everything back together. All looked good. I button everything back up, start the truck, and all is good... for about 10 minutes. I still have amber colored turn and flashers, but no switch to white all day UNTIL... went to park after a few hours of having no joy and boom!! They are on!!! Courtesy lights go out and I'm stoked that they are working so I start it back up..... no joy!! Anyone have an idea? Bad resistor? Bad connection? I almost think it's in the truck because BOTH are acting up..
parts used.
http://www.ebay.com/itm/281996710590
http://www.ebay.com/itm/231735970710
any ideas appreciated.

 

From what you are describing, it looks like the Daytime Running Lights (DRL) are set to turn signal.
So with the headlights off, as soon as you shift out of park the DRL kicks in and your parking lights switch to signal, causing the switchback to switch to amber.
As soon as you shift to park, the DRL turns off and your Switchback return to white parking light mode.

Your only options are to use Froscan to either turn off the DRLs, or switch them to something other than turn signal.

 

Yep, soaringfalcon is correct!