a good ground system is a must!!
I also paint all my grounds points w/ an anti-corrosive paste.
it does matter about combining regular bulbs with LED's.
LED's are polority sensitive
so
truck's hot +12v must go to hot +12v, gnd to gnd, of the light.
Flasher units work because the spring inside gets hot, they are heat sensitive and the spring breaks the contact w/in the flasher plug-in unit's contact.
http://auto.howstuffworks.com/turn-signal2.htmIn order for an LED to work as a blinker
you must either
1. change the flasher unit to an LED type
or
2. have some resistance in the same circuit as the LED so the stock flasher unit will activate the circuit. this resistance can be a normal bulb located in the front of the truck (incandesant blinker lamp). this also must have a good ground.
http://www.howstuffworks.com/framed.htm?parent=turn-signal.htm&url=http://knology.net/~rkmason/flashers.htm
