Turn signal gremlin(s) on HMMWV

[JGrant]

Here's the problem with my HMMWV...
Left turn signal on, left front works and rear does not.
Right turn signal on, and right front does not work and rear does.

What's the deal? Ground? Signal assembly? Where should I start and is this indicative of a common problem?

Hep!!

 

[jluv1185]

The bulbs good?...sorry had to ask.

 

[popacom]

Hey guys! I had a similar problem on an M-151A2 I had and it turned out to be the turn
signal control assy. ,the switching inside it normally disconnects the brake light signal on the side you are turning on and applys the flasher signal . When the turn signal controls get FUBARed
the contacts are not "making and breaking" correctly and you end up with a problem like you
have described,I would take a KNOWN good turn signal control and substitute it and see if this
affects the symptom yours is displaying. I hope this proves to help.

Thanks! popacom / BILL

 

[vtdeucedriver]

Normally I dont have a problem trouble shooting turn signals on my vehicle, but my current problem on my tractor is kicking my butt.

 

[TedG]

Clean all grounding points on all signal buckets and marker lights. Make sure the metal strap between the two signal bucket mounting bolts are intact and clean. Make sure all lamps are sized correctly and operational. Make sure engine ground harness is installed and the dash ground lug is cleaned and tightened. If you still have problems, replace blinker module under dash. Replace signal level if problem still exists.

 

[JGrant]

Problem Solved!

Bought a new turn signal switch and fixed the problem. Many thanks for the ideas, all.

 

[slash79]

ive had a problem similar to this, it turned out that the new marker unit i put in got its ground from a different bolt on the back. i was chasing gremlins for a while until i figured that one out, made me feel a little bit remedial. just something to think about if you replace the whole unit somewhere down the road

 

[RockHild]

Marine

Bought a new turn signal switch and fixed the problem. Many thanks for the ideas, all.

Having some turn signal issues as well on my '89 HMMWV and would like some pointers on best items to inspect 1st, all other lighting system works well, excluding turn signals, loosened plug on back, and can hear click, but lights are not blinking, got any suggestions?

Thx
RockHild

 

[DREDnot]

Start from the problem and work toward the battery. Replace the bulb with a known good unit to eliminate the easiest first, Then inspect and clean the socket contacts and socket barrel itself as its the ground path, then look for the power and ground wires and where they fasten and clean that connection. 7 times out of ten you will have found you problem in the signal bucket area.

 

[RockHild]

Thanks Sgt Maj,
Semper Fi, my '89 M998 is exactly the same style as your profile pic with 6.5, just began checking systems, am working on getting titled, registered and inspected and noticed the turn signals did not work. I appreciate the advice, have yet to turn a wrench or screwdriver on it. I am sure it is something simple, but owners who have had a Humvee for a while always have some good pointers. Will get back to ya on results.

Thx,
RockHild

 

[86m998]

I am having similar issues. 1986 M998 turn signals just stopped working & brake lights at same time. Confirmed all bulbs are good. Turn signals turn on but don't flash. Hazards switch does nothing; doesn't even turn them on solid. While diagnosing I notice brake lights will come on when pedal is depressed fully with significant pressure. I believe from other posts that the flashing module for turn signals if different than the one for turn signals so I think it's too coincidental that both would fail at same time. Any ideas?

 

[papakb]

DREDnot, had the same issue with my blackout lamp. The clear lens had fallen out and the lamp filled up with water. By the time I found it all I had inside was glass and iron oxide!

 

[RockHild]

86m998,
I found that the turn signal itself had some bad contacts inside and actually bent a couple of them and made it work all around, but soon became intermittent again, so I ordered another turn signal and all is working with new one, however the mounting with the new one was with a hose clamp and the original was actually bolted in so I used the housing of the old one and installed the contact section to the old frame and now all is well.

Rockhild

 

[papakb]

That switch is the same one AMG used on the M151A2 series and was mounted by a bracket and hose clamp. In the HMMWV the bracket is welded to the column and the switch attaches with 4 screws. The switch contacts do wear out over time and can be burnished to make them work again but it doesn't last. Replacing the switch is the best corrective action but be leery of the ones made in Asia. I always found it interesting that we scrapped thousands of 151s, Things like switches, gauges and headlights shouldn't be in short supply.

 

[RockHild]

That switch is the same one AMG used on the M151A2 series and was mounted by a bracket and hose clamp. In the HMMWV the bracket is welded to the column and the switch attaches with 4 screws. The switch contacts do wear out over time and can be burnished to make them work again but it doesn't last. Replacing the switch is the best corrective action but be leery of the ones made in Asia. I always found it interesting that we scrapped thousands of 151s, Things like switches, gauges and headlights shouldn't be in short supply.

True story, I am all good now and road worthy!

 

[RockHild]

My '89 M998 is ready for whatever and can legally drive wherever, it was a chore, but it is done !

 

[86m998]

Does anyone know if this switch contains the flasher unit or is that separate? https://www.ebay.com/itm/Military-Truck-Fit-HMMWV-Hummer-M998-Turn-Signal-Flasher-Switch-W-canceling-Ring/163713160417_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D3b6683ad3b8a478c961f1e3965db914b%26pid%3D100675%26rk%3D3%26rkt%3D15%26sd%3D113665876479%26itm%3D163713160417&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3Ae450fb0e-9862-11e9-9116-74dbd180ca4e%7Cparentrq%3A95ef39eb16b0a9c9e6a31424ffff4279%7Ciid%3A1

 

[papakb]

That's the newest of the turn signal switches but it does not include the flasher. This switch is used on several different vehicles and may or may not have the correct connector for the HMMWV. The "C" shaped piece in the picture is the self cancelling ring and has a small plastic pin that cancels the turn signal and is prone to breaking off. You can still use the switch without it but it reverts back to manual operation only.

 

[86m998]

Thanks! I have this switch now but with no self cancelling. I have to manually stop the turn signal which of course I forget to do and my wife calls me an old man!!

 

[Dotrat]

Hey All,
I am kind of having the same problems but mine goes like this. My front turn signals operate normally but my rear signals go bright as if I was pushing the brake pedal but do not blink? I am not sure why because the fronts blink normally!