LED Tail Light Resistor Question. .

[Already Gone]

I've had the United pacific LED Tail Light in my 72 C10 for 3/4 years now. I added the Electronic LED flashers when I installed them and they flash just a little quicker that with the stock bulbs. I am changing up to an LED Board, made by a board member, so will be adding Resistors to my tail Lights.My Question is do I need resisters on each tail light or just one side ?

[dmjlambert]

One for each side. But since your flasher works with LED lights and you don't have resistors now, you probably won't need resistors.

[Richard]

The resistors will have no effect on the led flasher. Flash timing is electronic, not based on load. If you want to go back to a standard flasher, yes install the resistors. The resistors can get pretty hot. Careful where you mount them if used.

[Already Gone]

Originally Posted by Richard

The resistors will have no effect on the led flasher. Flash timing is electronic, not based on load. If you want to go back to a standard flasher, yes install the resistors. The resistors can get pretty hot. Careful where you mount them if used.

Thanks for the info. I tried using LED bulbs in my front marker lights but couldn't get my side marker lights to work with the LED Bulbs. Im hoping resistors on the marker lights wil cure that problem.

[Richard]

Originally Posted by Already Gone

Thanks for the info. I tried using LED bulbs in my front marker lights but couldn't get my side marker lights to work with the LED Bulbs. Im hoping resistors on the marker lights wil cure that problem.

Maybe you already tried it, just flipping the bulbs can make them work. Led's are polarity sensitive.

[dmjlambert]

Side marker lights would require non-polarity bulbs, so I recommend don't go LED there. When they are lit for parking lights the polarity is one way, and when they are blinking for turn signals the polarity is reversed.

[Richard]

Originally Posted by dmjlambert

Side marker lights would require non-polarity bulbs, so I recommend don't go LED there. When they are lit for parking lights the polarity is one way, and when they are blinking for turn signals the polarity is reversed.

Believe only the 71-72 alternate with the turn signals. 69-70 have a +12v from running lamp circuit and go straight to ground.

71-72, I had thought the markers were grounded by the front turn circuit + wire and blinking happened when front turns came on, eliminating the ground. That is why they alternate. Will have to look into the 71-72 circuit more.

[dmjlambert]

Yes, I agree. 69-70 have a +12v wire for when headlights or parking lights are on, and no blinker involvement. My 69 was apparently early in the year and just had reflectors instead of marker lights. I wired it up in the 71-72 way, so it is useful as a blinker or as a solid glowing marker light. The 71 and later service manuals show the wiring diagrams in a different style compared to 70 and earlier, and I think the 71-72 wiring diagram is more difficult to follow. The 70 and earlier diagrams are the ones that are adapted to color in the electrical section of the forum. I made a diagram of the side marker wiring in color and showing both plain glowing light and combo parking light and blinker options here in this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=763813