Grote 10-34V Military LED Taillights not flashing, MRAP take offs

[Jeep Nasty]

First off, I am using the flasher box rated for LED's so its not that.

Grote 10-34V Military LED Taillights

"Like New" MRAP Take Offs"


I bough a pair of these from the classifieds section

So I have got my fronts and rears hooked up and installed. Everything works fine when the 3 lever switch is on Stop/ turn mode. However, when in service drive, the rear turn signals won't flash. the front turn signals work fine but the rears just stay solid. The parking lights are on and when I flip the turn lever, that side gets brighter but won't flash. I thought it could be a flasher problem, but I tried 3 different flasher boxes that are all rated for LEDs or combination LED and conventional.

Any ideas or has anyone else experienced this problem.

Is anyone else having a problem with these rears not flashing properly.

 

[goldneagle]

How about swapping the 3 lever switch for another.

 

[Jeep Nasty]

How about swapping the 3 lever switch for another.

I'm actually dumbfounded that that didn't even cross my mind till you just said it. I wasn't thinking that, because service drive worked fine before the LED swap, but you never know. I'll try my extra switch after work.

 

[MyothersanM1]

If not the 3-lever, do you have LED's already and do they flash properly? If no, make sure your flasher box is LED compatible. The earlier boxes will not flash LED's.

 

[mkcoen]

One thing I noticed when swapping to LEDs on my M1101 was the extra ground wire compared to the standard lights and had to add a loop to the vehicle ground. Not sure it would make a difference but I've found many times with electrical gremlins it goes back to the ground.

 

[Jeep Nasty]

If not the 3-lever, do you have LED's already and do they flash properly? If no, make sure your flasher box is LED compatible. The earlier boxes will not flash LED's.

Led front turn signals work fine in either mode on the switch.

 

[goldneagle]

Led front turn signals work fine in either mode on the switch.

Just remember that the read lights also do the BRAKE light. On many vehicles the brake and turn signal use the same element on the bulb.

 

[Csm Davis]

Sounds like a crossed wire on the rear

 

[Jeep Nasty]

Sounds like a crossed wire on the rear

I'll report back when once I try a different switch after work. The strange part about it is when the 3 lever switch is in park/light mode on top switch, the rear turn/stop work fine and flash properly, just not in service drive. In service drive, the rears both illuminate the "dimmer" led's for the tail lights and when the turn signal is activated the brighter ones turn on, on the activated side without flashing.

 

[MyothersanM1]

Led front turn signals work fine in either mode on the switch.

Then the flasher box is good.

One thing I noticed when swapping to LEDs on my M1101 was the extra ground wire compared to the standard lights and had to add a loop to the vehicle ground. Not sure it would make a difference but I've found many times with electrical gremlins it goes back to the ground.

^^Agreed. I would go here next. The LED upgrades have to be grounded with that extra wire. They do not ground through the threaded bucket attachment points like the standard incandescent lights do. Also, for safe measure, I installed a grounding strap from the bed underframe to the chassis.

 

[Ferroequinologist]

If they work in stop/turn, but not in service, the only variable changed is the contacts in the light switch. I would pull the cable off and hook another up under the dash, before you pull the old switch, and test.

If the grounds were bad they wouldn't work in either mode.

 

[73m819]

Sounds like the REAR RUNNING lights are BACK feeding into the brake/turn circuit, this is most often caused by a BAD GROUND or miss wired, since all worked before the change, I would start adding/checking grounds.

 

[Jeep Nasty]

Now I'm confused and pretty sure I have two bad,3 lever switches. I plugged in my other switch that I thought was new.
nothing worked while on stop/ light mode and when on service drive, the rear brake and turn signals worked, but the headlights and running lights would not come on.

i double checked grounds I added to the rear taillights when mounting the lights since these are not grounded through the housing. I made sure I had sanded down to bare metal and everything was tight.

so I think I need another switch to try.

 

[Jeep Nasty]

Alright now I need some ideas. I should have a another switch to test tomorrow. Today, I picked up my M105a2 trailer, when I plugged in the trailer and put the switch to service drive. Everything worked correctly. The led tail/turn stop and the trailer lights all flashed correctly. When I unplugged the trailer, the same problems persisted. Could this still indicate a bad switch or flasher because the led is not triggering the correct voltage?

 

[gimpyrobb]

I would think so. I can't remember if you tried different flasher units.(might want to try it)

 

[Jeep Nasty]

And... I'm lost. I've swapped out flasher units, 3 lever switches, turn signal switch, checked all the grounds, bench tested the rear lights, the rear turn signals just won't flash when in service drive. Rear turn signals work fine on park/ light setting. Front turn signal Led's work fine on all settings. I can only guess that when the tail lamps are on and turn signal is activated, something is just off with the flasher with this combination not allowing it to work. If I plug in my m105a2 trailer, turn signals on truck & trailer work in service drive.

 

[Csm Davis]

Okay STOP! Quit shotguning it take the wires lose from one light and plug in one old regular light and see if it works, if it works you have a problem right there at the led light. If not then back up to the turn switch and then to the three lever switch checking them with a volt ohm meter.

 

[infidel got me]

Good call j.d.ill put my money on a ground issue.make sure frame/undercarriage is clean free of rust paint etc.we sometimes have used jumper cables to ground things.if lites function with trailer attached it most likely is a ground.good luck-take your time im sure you will figure them out

 

[Swamp Donkey]

Pull the indicator bulb from behind the green lens on the blinker switch and troubleshoot with it removed. If everything else is wired correctly then that should fix your problem because the blinkers will flash with that bulb missing. That little incandescent bulb can cause backfeeding that confuses the flasher unit. The bulb can be replaced with a 24v LED bulb to remedy the back feeding problem. The bulb base is a BA9S.

Removing that bulb prior to troubleshooting should be the first thing you do, even before checking grounds and the flasher relay. It takes 2 seconds and can be checked by flipping the blinker switch right after it's removed. Not saying the other things don't need to be checked, just that it's simple to check before you even get out of the cab.

I ran into this same situation on my truck. Checked all grounds, all connections were good and correct, tired 2 different LED flasher relays, tried 2 different flasher switches (one new style and one old style), and tried 2 different head light switches. I still could not get the fronts to flash, but the rears worked fine. I removed the bulb and everything works. I replaced with an led bulb and everything works as it should.

I have Truck-lite in the front, Grote in the back and installed Erik's parking light adapter cable.

 

[Jeep Nasty]

Winner, winer, chicken dinner. you very much. As soon as I pulled that bulb, all was good.

Pull the indicator bulb from behind the green lens on the blinker switch and troubleshoot with it removed. If everything else is wired correctly then that should fix your problem because the blinkers will flash with that bulb missing. That little incandescent bulb can cause backfeeding that confuses the flasher unit. The bulb can be replaced with a 24v LED bulb to remedy the back feeding problem. The bulb base is a BA9S.

Removing that bulb prior to troubleshooting should be the first thing you do, even before checking grounds and the flasher relay. It takes 2 seconds and can be checked by flipping the blinker switch right after it's removed. Not saying the other things don't need to be checked, just that it's simple to check before you even get out of the cab.

I ran into this same situation on my truck. Checked all grounds, all connections were good and correct, tired 2 different LED flasher relays, tried 2 different flasher switches (one new style and one old style), and tried 2 different head light switches. I still could not get the fronts to flash, but the rears worked fine. I removed the bulb and everything works. I replaced with an led bulb and everything works as it should.

I have Truck-lite in the front, Grote in the back and installed Erik's parking light adapter cable.