Blinkers/Hazzards stop working when headlights turned on...

[SlickGTP]

I haven't been able to spend a lot of time on this, but fuses have been checked... Not sure if this is happening on account of the new printed circuit I installed, my tinkering with my dual tank set up, or some other failure.

Another thing that is weird is when I switch between the tanks, the brake light and blinker indicators flash.

I'll go through it all here before too long, but I was just looking for ideas as to what might be the cause or if anyone else has had a similar issue so that I can put together a game plan when I actually get to the investigation.

Thanks!

 

[89Suburban]

 

[foamypirate]

First thing I would check is your grounds. Sometimes if you don't have a good ground, it can backfeed through other circuits trying to find a ground, which makes weird things happen.

 

[SlickGTP]

I know... makes me wonder what the truck's been smokin'

First thing I would check is your grounds. Sometimes if you don't have a good ground, it can backfeed through other circuits trying to find a ground, which makes weird things happen.

Thanks! I really haven't touched any grounds lately other than on the tank sending units and I made sure those were good, but I'll check the grounds out first chance I get.

 

[SlickGTP]

DOH! Well I feel stupid now... Got home and realized that the tail lights are grounded to the bed which was insulated from the frame by a few pieces of 4x4 timber. At least I know how things behave with the lights when missing a major grounding point.

 

[guitarfreak235]

im having the exact same problem.... BUT only when i have leds in the front parklights.....

 

[SlickGTP]

im having the exact same problem.... BUT only when i have leds in the front parklights.....

Hmmm... My thought is if the LEDs are the ones that need to be put in a certain way. Unless they have the circuitry to make it where it doesn't matter. By their nature, LEDs only allow current in one direction.

The other thought that I have is whether or not you have a bi-metal flasher unit or a newer capacitor driven flasher. you'll need the new style flasher to work with LEDs. The LEDs don't draw enough current to heat up the bi-metal flasher fast enough to work properly.

 

[guitarfreak235]

Hmmm... My thought is if the LEDs are the ones that need to be put in a certain way. Unless they have the circuitry to make it where it doesn't matter. By their nature, LEDs only allow current in one direction.

The other thought that I have is whether or not you have a bi-metal flasher unit or a newer capacitor driven flasher. you'll need the new style flasher to work with LEDs. The LEDs don't draw enough current to heat up the bi-metal flasher fast enough to work properly.

yea i know they only work one way, i always check to be sure theyre the right way before i put the lenses on. i have both flasher units replaced with electrical ones.... the only thing i can think of is that it has to do with the unit that alternates the park lights and the side markers... i only had the front parklights replaced with leds, the sides were still the original bulbs, so im hoping itll be fixed when those are leds too. it must have to do with current draw or something. with the headlights on the leds shine bright but the side markers barely glow at all. must be wired in parallel and the leds just have much lower resistence.

 

[89Suburban]

Those front turns and side markers have some kind of weird ground setup to get them to flash alternately, I'll will have to go refresh my memory....

 

[guitarfreak235]

Those front turns and side markers have some kind of weird ground setup to get them to flash alternately, I'll will have to go refresh my memory....

ok thanks, ya think itll work if both lights are low current draw/ resistence? i hope the dissimilarities between the led and regular wedge were the culprit

 

[89Suburban]

Somehow those side marker lights ground through the the turn signal bulb. So when the bright part of the two filament bulb flashes on, it cancels the ground of the side marker and it goes out. Then when the bright part flashes off the side marker grounds through the bulb filament to the frame. Very hard for me to explain. My guess is using LED's in the turn signal itself may keep that ground from being created since it acts like a diode.

In other words, I have LED's in my side markers and they work fine, and they flash alternately with the turn signals. But I believe it I added LED's to the turn signals that would cause a problem with the side markers. Make any sense? I could be full of **** too, I just don't know the answer for the turn signal bulbs themselves, That's just my guess.

 

[89Suburban]

I tried to color the wires in question here, brown and Lt Blue:

 

[guitarfreak235]

I tried to color the wires in question here, brown and Lt Blue:

hmm to me they look parallel? but i dont have prior experience with this anyway. from what you can tell would i be able to reground them easily? if i have time tomorrow i'll replace the side marker too and see if it works then. im confused as to how it would work without the parklights on tho..

 

[89Suburban]

hmm to me they look parallel? but i dont have prior experience with this anyway. from what you can tell would i be able to reground them easily? if i have time tomorrow i'll replace the side marker too and see if it works then. im confused as to how it would work without the parklights on tho..

You know what man? This is really got to me. I think since I am going to be rained in all weekend I might make a mockup of this system in the garage and do a special how to video of how this works and what exactly is happening. I think I may even have a LED combination park/ turn bulb to throw in the mix to see how LEDs affection the function. Yup, I got a project this weekend, stay tuned....

 

[89Suburban]

Here, this pretty much sums it up. Based upon this I don't see alternating turn lights using a LED turn bulb unless they make them special or have a electronic doo-hicky to make it work.

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