Flashers Do Not Work (Unless)

[Keoni_M1123]

Searched for a few days here and could not find this particular issue:


2003 M1123
Only LED are headlights
Flashers stopped working a few weeks ago. Headlights, running lights, stop lights all work.

After research, bought new control switch. Did not solve problem. Next purchased a new flasher module. When connected temporarily (not mounted), flashers (turn signals) flashed as normal as well as all running lights, headlights, stop lights etc.

Once the new flasher module was mounted and connected, flashers no longer worked. However, the signal bulb does come on bright (static "non-flashing") when the control switch arm is in position. The bulb remains on until the control switch arm is moved out of position. This is true for left, right and hazard.

I have 3 control switches one older and two new. They all behave the same.

Any insight is appreciated.

Thanks,

Johnny

 

[Mogman]

Welcome to the SS forums!!

 

[Atchuuu]

I have the same issue. Did you just change the flasher module with the original part number or a LED version?

 

[Mogman]

The question that comes to mind is, where did you buy the flasher and turn signal switch.

 

[Barrman]

I don’t have a HMMWV. But, the same parts are used on my M35 and M715 trucks for the blinker system. Your “new” blinker box is almost broken is my thought. My M715 unit does just as you describe. If you leave it on for a few minutes, it might start blinking like normal. At least mine does. Sometimes.

I have swapped in a known good unit and all is well. So, I know it is just the blinker box. I put it back in and live with the ”mood” of the switch because those things are too expensive to just throw out.

Here is a video about how to test the blinker box:

 

[Atchuuu]

I don’t have a HMMWV. But, the same parts are used on my M35 and M715 trucks for the blinker system. Your “new” blinker box is almost broken is my thought. My M715 unit does just as you describe. If you leave it on for a few minutes, it might start blinking like normal. At least mine does. Sometimes.

I have swapped in a known good unit and all is well. So, I know it is just the blinker box. I put it back in and live with the ”mood” of the switch because those things are too expensive to just throw out.

Here is a video about how to test the blinker box:

Great video. Thank you.
Will the original flasher box work with LED lights? From what I have read, even if the box tests good, it may not work for LED. Are you running LED lights?

 

[Barrman]

I am pretty sure I had all LED big bucket lights at all 4 corners on my M715 before I painted it and went correct for it small bucket lights. The blinkers worked. But, that has been 18 years.

I know I had LED buckets on my 35A2 before I got tired of them failing one diode at a time and went back to bulbs when I rewired it 7 years ago. Good blinkers then too.

 

[Atchuuu]

My flashers are working with all LED bulbs but….

1. my high beams are not working. Checked ground and all the connections. Nothing when I toggle the dimmer switch.

2. flashers work when there is no bulb in the indicator socket or when there is a good led light in there. But the indicator does NOT light up. Bulb is good. I cleaned the socket good.

The turn switch was in very good condition.

Any suggestions on high beam or indicator light.

 

[Mogman]

My flashers are working with all LED bulbs but….

1. my high beams are not working. Checked ground and all the connections. Nothing when I toggle the door switch.

2. flashers work when there is no bulb in the indicator socket or when there is a good led light in there. But the indicator does NOT light up. Bulb is good. I cleaned the socket good.

The turn switch was in very good condition.

Any suggestions on high beam or indicator light.

Check the LED indicator bulb, it should be "backwards" meaning the positive goes to the shell and neg goes to the contact point, easy enough to test with a couple test leads.

 

[Atchuuu]

Thank you. I might have the wrong bulb.

 

[Atchuuu]

I pulled the headlight to check voltage at high and low beam. Not super familiar with a multimeter but have no trouble checking voltage on batteries. I put negative on 91 lead and positive on 17 and I’m getting crazy readings. Switches to 18 and get a low negative reading. Am I going about this wrong?

 

[Mogman]

I pulled the headlight to check voltage at high and low beam. Not super familiar with a multimeter but have no trouble checking voltage on batteries. I put negative on 91 lead and positive on 17 and I’m getting crazy readings. Switches to 18 and get a low negative reading. Am I going about this wrong?

You have nothing there, the meter is only reading mV so the 130 = .13V
What I would do at this point is make sure you have good voltage going in and out of the dimmer switch.

 

[Mogman]

I would leave the wires attached and use the meter lead to pierce the wire insulation, 16 is feed (should be 24V no matter what the switch position is in (with the light switch in service drive ) 17 is high beam and 18 is low beam.

 

[Atchuuu]

I installed both headlights again. The low beam was working fine. Pulled one light and tested voltage at #17 which I believe is low. Had 16.27 volts. Put the probe in #18 and got a consistent 24.86.

then I hit floor switch to switch to high beams and the meter was all over the place.

 

[Atchuuu]

I would leave the wires attached and use the meter lead to pierce the wire insulation, 16 is feed (should be 24V no matter what the switch position is in (with the light switch in service drive ) 17 is high beam and 18 is low beam.

Which wire do I ground to when I test dimmer switch? And, thank you! I appreciate the reply and advice.

 

[Atchuuu]

I’m looking at my dimmer switch and wondering if it is wired correctly. From left I have 16,17 and 18. Looking for wiring diagram now.

 

[Mogman]

I installed both headlights again. The low beam was working fine. Pulled one light and tested voltage at #17 which I believe is low. Had 16.27 volts. Put the probe in #18 and got a consistent 24.86.

then I hit floor switch to switch to high beams and the meter was all over the place.

I just said in the above post that 17 was high and 18 was low

 

[Mogman]

Which wire do I ground to when I test dimmer switch? And, thank you! I appreciate the reply and advice.

You ground the negative lead to the engine or other good ground

 

[Keoni_M1123]

I have the same issue. Did you just change the flasher module with the original part number or a LED version?

You ground the negative lead to the engine or other good ground

Non LED version as I am not running LEDs.

 

[Atchuuu]

You ground the negative lead to the engine or other good ground

24 volts at 17 and 18 so switch is working. Must be bad high beams. They were the cheap version. Low beam works but they get a lot of condensation and on low they aren’t that bright