LED 1057 bulb issues

[Casper42]

I have LED's bulbs throughout my 1972 C10 - like 1157s and 1156 for instance, but cannot find anything to work in the front bumper parking/turn lights for the life of me. The only thing that will work is 1157 incandescent, and strangely working perfectly in synch with all the LEDs. I have two electronic grounded flashers in the fuse panel. Every other light on the truck is LED, inside and out. nothing involves those LED printed circuit boards that some manufactures are selling as an all in one light.

The issue is: 1) any LED 1157 will cancel out my front fender marker lights, however the turn indicators in the fender work fine. 2) the LED 1157's in the bumper are on hyper bright, meaning the second stage of it's design like a bright brake light.

Mind you, it's a challenge to find compatible 1157 LEDs that will even work up front, as the design of the socket is more shallow than normal, so many 1157 LED's bottom out and you can not turn them to lock them in place. I've found 4 LEDs that don't bottom out, however every one does the same oddity as described #1 above. All four of these range in lumens from about 300 up beyond 1000, reportedly. Even the Retrobrights with the traditional look from Holley/Brothers fail.

Yes, even if I take out the current 1157 LEDs from the tail lights, they do the same failure up front.

I'm about stumped. Any suggestions? I appreciate your thoughts

[dmjlambert]

I think you should probably be looking for 1157 (turn and tail) and 1156 (backup lights) bulbs, not 10-something. Perhaps that is the problem.

[dmjlambert]

The bulbs that go in the front marker lenses should be 194 bulbs and it is best to use incandescent. I don't believe you would gain anything by trying to use LEDs there because that bulb gets forward polarity sometimes, and reverse polarity at other times. LED bulbs usually require a specific polarity, they depend on you plugging them into a socket that will always give positive voltage on the same terminal all the time.

[Casper42]

Originally Posted by dmjlambert

I think you should probably be looking for 1157 (turn and tail) and 1156 (backup lights) bulbs, not 10-something. Perhaps that is the problem.

ha. no it's not. the problem was me having "10" on my mind all day. thanks for correcting, as I clearly know my bulbs

[Casper42]

Originally Posted by dmjlambert

The bulbs that go in the front marker lenses should be 194 bulbs and it is best to use incandescent. I don't believe you would gain anything by trying to use LEDs there because that bulb gets forward polarity sometimes, and reverse polarity at other times. LED bulbs usually require a specific polarity, they depend on you plugging them into a socket that will always give positive voltage on the same terminal all the time.

the 194 are actually the "side marker lights" just to avoid any confusion - interpretation of naming the lights correctly.

[dmjlambert]

Whoops, sorry I meant front side marker lights are 194 and I recommend putting some incandescent bulbs in that spot to prevent LED not working insanity. Rear side marker lights can be LED, although there is no advantage to use LEDs there either.

[Casper42]

Originally Posted by dmjlambert

Whoops, sorry I meant front side marker lights are 194 and I recommend putting some incandescent bulbs in that spot to prevent LED not working insanity. Rear side marker lights can be LED, although there is no advantage to use LEDs there either.

fail. I just tried what you suggested, swap out 194 LEDs back to incand and then the front bumper 1157s with incand to the LEDs. zero change. thanks for the idea as I had not tried that configuration before. back to the drawing board. Ugh

[Richard]

The leds in the front turn signal are what is keeping the front sidemarkers from lighting. On 71-72 trucks the front sidemarkers alternate flashing with the front turn. The way this is done is the sidemarker is grounded through the front turn element (69-70 are direct ground). The led will not allow the marker circuit to pass to ground. You can use a standard bulb in the front running/turn location and the sidemarker will work. You can directly ground the sidemarkers and they will light but not flash. A relay or diode circuit could be added to front markers.

[Casper42]

Originally Posted by Richard

The leds in the front turn signal are what is keeping the front sidemarkers from lighting. On 71-72 trucks the front sidemarkers alternate flashing with the front turn. The way this is done is the sidemarker is grounded through the front turn element (69-70 are direct ground). The led will not allow the marker circuit to pass to ground. You can use a standard bulb in the front running/turn location and the sidemarker will work. You can directly ground the sidemarkers and they will light but not flash. A relay or diode circuit could be added to front markers.

thank you, that makes sense, but wayyyyy above my pay-grade to do. haha. It sounds like I'll stick with incandescent in the bumper and LEDs in the side markers for the time being.

[Richard]

Originally Posted by Casper42

thank you, that makes sense, but wayyyyy above my pay-grade to do. haha. It sounds like I'll stick with incandescent in the bumper and LEDs in the side markers for the time being.

Hope this helps you out Using standard bulbs in the front there should be no problem using the 194 led in the sidemarker, just need to insert it with correct polarity like you did on rear sidemarkers. In some cases the led will still light in a circuit like this even when off depending if circuit is + or - switched because the led requires very little wattage. Cannot remember off hand which way the circuit is. The wiring diagrams provided in the electrical section only are for the 69-70 trucks unfortunately.

Edit- it was said the front marker lights switch polarity at times, they do not. They just receive +12v at both sides of the bulb as front turn illuminates. +12v to +12v is not a short, but also not a complete circuit so marker goes on and off opposite of front turn.

[dmjlambert]

If you get 194 LED bulbs in the front side marker and 1157 incandescent bulbs in the parking lights, and headlights are off, and it works, then the front side marker lights should stop working when you turn on the headlights.