'86 M998 Humvee issue with headlights and turnsignals

[twisted60]

First I did a search, I found lots on turn signals but did not find any on my issue. So here it is...
I have LED lights all the way around and an LED bulb in the turn signal switch.
Turn signals work good until I turn on headlights, then no more turn signals. Headlights on, turn signals not working. So what I've done so far....
Tried with 3 lever and push button light control switches, no change. Tried 2 turn signal switches, no change.
Tried 2 mechanical and 3 solid state flasher units, no change. Tried 3 different LED bulbs in turn signal switch, no change. I must be missing something but what ?
Any ideas ?

 

[papakb]

I run LEDs all around, Truck-Lite headlights and BO driving light, LEDs in every position including the instruments and turn signal indicator with no problems. The only place I don't have LEDs is the BO taillights.

 

[Klaeq]

I'd say double check all your grounding. Make sure all contacts are clean of paint and making good contact.

 

[Milcommoguy]

Later model lamp buckets used LED's in the BO / Stop locations. Personally, I like the old school incandescent bulbs.

Moving at the speed of light, CAMO

 

[DREDnot]

I put LEDs in the dash. Big improvement. Went to put one in the turn switch indicator...it doesn't work there. Tried three different styles of bulb...no go.
Im starting to think that because its wired in such a way that its on when the flasher switches to off and consequently doesn't have the correct polarity for an LED bulb there.
I would like the bright LED to remind me its still on in the daytime, but its still incandescent at the moment.

 

[Bulldogger]

I second the advice to investigate all your wiring for both the turn signals and the headlights. Sure sounds like a short somewhere. Don't forget to look INSIDE the headlamp cavities, behind the LED headlights. There are connections there too. On my rig the connections inside the hood, the other side of the headlights went bad. Wiring diagrams are on this site in the TM section if you need them.
Bulldogger

 

[papakb]

Make sure your connections in the headlight bucket are correct. 91 is the ground feed to the light and you don't want either the 17 or 18 wires from the LED connected to it.

 

[twisted60]

I may not have been clear. Headlights work normally. Turn signals work normally. Problem is when I have head lights on that's when my turn signals no longer work until I turn headlights off then turn signals work again. So I'm thinking it has to be something they share,,,? Voltage drop ? If I had a bad ground one or the other would not work, right ? I'll keep trying.
Thanks for the comments so far

 

[Coug]

The main thing that they share is the light control switch.

A bad ground somewhere might cause power to feed back through a different circuit than is intended, so there is that possibility.
You mentioned that you tried a different light switch assembly, it's unlikely that both have failed in the exact same way (but not impossible), so I'd be more inclined to start troubleshooting the wiring and connections at that point.

 

[twisted60]

The main thing that they share is the light control switch.

A bad ground somewhere might cause power to feed back through a different circuit than is intended, so there is that possibility.
You mentioned that you tried a different light switch assembly, it's unlikely that both have failed in the exact same way (but not impossible), so I'd be more inclined to start troubleshooting the wiring and connections at that point.

Thanks, I pulled up the wiring schematic and started tracing wires, I see the BO light shares a ground with the turn signals and it is still the original light, tomorrow I'll replace it with an LED and start checking/cleaning grounds. The only time its an issue is at night not being able to signal a turn but then again I am in Florida and no one uses them anyway... hahaha

 

[gem1410]

I have a 1997 ecv--same situation with the led lights--I removed the bulb from the turn signal switch and all led lights work now even with the head lights on--also noticed the turn signal switch has the ground and power reversed going to the bulb so that an led bulb will not work on the turn signal switch--

 

[osteo16]

I have a 1997 ecv--same situation with the led lights--I removed the bulb from the turn signal switch and all led lights work now even with the head lights on--also noticed the turn signal switch has the ground and power reversed going to the bulb so that an led bulb will not work on the turn signal switch--View attachment 799272

BA9S reverse polarity LED will work in turn signal from what I've read... Reviving old threads, one strand at a time

 

[Maxjeep1]

BA9S reverse polarity LED will work in turn signal from what I've read... Reviving old threads, one strand at a time

This is what’s needed for the center of the turn signal indicator? Mine doesn’t work and I’m looking for a replacement bulb

 

[osteo16]

This is what’s needed for the center of the turn signal indicator? Mine doesn’t work and I’m looking for a replacement bulbView attachment 845826

Yup

 

[papakb]

This is going to sound stupid but they do make AC LED lamps that will accept either polarity to turn on.

Amazon.com

 

[Milcommoguy]

This is going to sound stupid but they do make AC LED lamps that will accept either polarity to turn on.

Amazon.com

WHAT ???

Now some do have a diode bridge to steer the voltage to the anode.

Any LED when powered with AC will illuminate when forwarded biased. (assuming forward voltage and current requirements are met)

That's why those cheap Christmas LED strings have that flicker to them. 60 Hertz my eyes 30 times times a second. LOL

Look closely. AC only on half the time, CAMO

 

[Maxjeep1]

I would be happy with the factory bulb. I don’t think I need anything brighter. I tried the federal led dash light bulb in it but it didn’t work. I might have a problem other than bulb.

 

[MarkM]

As stated I would look for a grounding issue with the blinker circuit.

Mark

 

[Milcommoguy]

There are 24 volt incandescent bulbs with higher CP and likely draw a little more current. The end result one is going to melt the plastic lens.

When your hot you're hot, CAMO

 

[98Non-Turbo]

I'm having the same issue. How did this get resolved?
Thanks!