[James]

Originally Posted by Harleyq

First try changed all the bulbs out hit the turn signal and both front came on a the same time. After scratching my head for a moment, or two, I realizes I needed resistors.

Both front turn signal can turn on because they require very litttle current. The way our truck is wired, power from one turn signal light is feed thru the turn signal indicator light (from the front lights only) to the oppsite light. Adding a load resistor parallel to each bulbs will prevent this. Also without the resistors the turn signal indicator may (very dim) or may not light up. Resistors are also needed if using the OEM style flasher. The OEM flasher has a bi-metalic spring that heat up causing it to break the circuit. Like FetchMeAPepsi says, using an electronic flasher help. If using an electronic flasher you would only need the resistors on the front lights and not required for the back lights. And yes, they won't work if plug in wrong, polarity matter. Also do not use a LED turn signal indicator bulb, because of polarity it would only flash in one direction and not the other.

Truck wiring can be modifiy to do away with the resistors, but it would require to know where to modifiy and the experence in wiring to do it right.

Originally Posted by Harleyq

During all this other issues have arised along the way. R rear parking light doesn't work, while left side the brake light stays on.

This sound like a turn signal switch gone bad. This is where the magic happen, it cancel the brake light and turn on the turn signal when selecting a turn.