Need help with front signals, and tail lights...

[BrwnDevil]

Hello,
I have a 71 GMC C15. I recently switched all my lighting over to LED.
I have installed two LED flashers, both are grounded...
My issue is that my front marker lights with led bulbs don't come on, when I switch back over to the normal filament style bulb they are very dim.
When I use the turn signal the LED bulb with flash once....if I wait a couple seconds and try it again I get the same result, with old style they work properly, but stay extremely dim.

The brake light/tail lights work properly until I turn the lights on then they do not blink, they just light up and stay bright, no flashing.

I have done my best to take a look at all the grounds, everything looks good.

I have read many many many previous posts about dim lights and lights not working correctly, but no one has seemed to have the issue I have.

Any help would be appreciated, thank you in advance.

-Shaf

[LockDoc]

Originally Posted by BrwnDevil

Hello,
I have a 71 GMC C15. I recently switched all my lighting over to LED.
I have installed two LED flashers, both are grounded...
My issue is that my front marker lights with led bulbs don't come on, when I switch back over to the normal filament style bulb they are very dim.
When I use the turn signal the LED bulb with flash once....if I wait a couple seconds and try it again I get the same result, with old style they work properly, but stay extremely dim.

The brake light/tail lights work properly until I turn the lights on then they do not blink, they just light up and stay bright, no flashing.

I have done my best to take a look at all the grounds, everything looks good.

I have read many many many previous posts about dim lights and lights not working correctly, but no one has seemed to have the issue I have.

Any help would be appreciated, thank you in advance.

-Shaf

Even though the older threads and posts may not have the exact same problem as yours the solution may be the same. Bad grounding. I won't say that this is the solution in every case but I bet it is in 90% of the weird electrical issue cases. Some problems can be in the headlight switch or turn signal switch but I would start with the grounds.

Read through this thread and make sure you have all of the factory ground straps listed and that all of the connection locations have bare metal contact.....

http://67-72chevytrucks.com/vboard/s...d.php?t=422234

There are some good tips and suggestions all through the thread.

LockDoc

[Sheepdip]

Like Lock Doc say's more than likely a grounding issue.

I never had any luck with those LED flashers I use these from Amazon. They are cheap, easy to install and they bring em to ya. You keep the original flasher with these and I have found that 1 each side in a easy to reach area like your front turn signals will put enough load for the front and rear lights of the side to which it is wired.

https://www.amazon.com/CUTEQUEEN-TRA...6532433&sr=8-3

[71gmcC15]

Originally Posted by Sheepdip

Like Lock Doc say's more than likely a grounding issue.

I never had any luck with those LED flashers I use these from Amazon. They are cheap, easy to install and they bring em to ya. You keep the original flasher with these and I have found that 1 each side in a easy to reach area like your front turn signals will put enough load for the front and rear lights of the side to which it is wired.

https://www.amazon.com/CUTEQUEEN-TRA...6532433&sr=8-3

What's the poin of LEDs if you have to have a resister. You basically defeat the point. Less energy draw. Did you try the United Pacific ones. I have one and it work great. But at the end of the day what ever makes you happy. And ya I'd say grounding. LEDs are even more picky about it.

[Andy4639]

2 things to remember about LED lights.
#1 They are polarity sensitive, You can have the wires crossed up at all anywhere in the system.
#2 Grounds and flashers have to be good for them to operate correctly.

[Sheepdip]

Originally Posted by 71gmcC15

What's the poin of LEDs if you have to have a resister. You basically defeat the point. Less energy draw. Did you try the United Pacific ones. I have one and it work great. But at the end of the day what ever makes you happy. And ya I'd say grounding. LEDs are even more picky about it.

I just answered the guy's question with a possible solution, don't get your panty's in a wad!

[Andy4639]

Something you can do also but is time consuming. Take all the LED out and put the regular bulbs back in. Then start replacing one set of bulbs at a time. Start with the brake tail light's. Then check and see if they work. Go through all the functions as with headlights On?OFF then turn signals with lights on/off. If they work move on if not find the problem.

[BrwnDevil]

Thanks for the help, I'll try and trace out all the grounds again tonight.
I'm just puzzled as to why my rear tail lights only flash with the headlights/marker lights off. The front park lights work fine...

[Andy4639]

Originally Posted by BrwnDevil

Thanks for the help, I'll try and trace out all the grounds again tonight.
I'm just puzzled as to why my rear tail lights only flash with the headlights/marker lights off. The front park lights work fine...

Has anybody messed with the head light switch lately?

Some of those switches are not as good as others. But I suspect your housing out back may need some work. The tail light housing grounds through the 2 screws that you install it with. Make sure they ground it good.