A question about M35A2 running lights

[rattlecan6104]

Sorry to bust your bubble, Cleveland Iron, But I just did the jumper wire mod the other day, and got the same results you got without the diode. Headlights stay off in park, and with the headlights on, my front markers are on as well. My jumper wire connected circuits 491 and 21. As a refresher for those that are unclear of what these circuits power, circuit 491 powers the front marker lights only, and circuit 21 powers the tail lights only. Neither of these circuits power the leadlights. If you would have tapped into circuit 16 which runs from the three lever switch to the headlight dimmer switch, then I could see where a diode may be needed, however with the way I described earlier, there is no need for a diode.

 

[Cleveland Iron]

You are right, and when you are right, you are right.

 

[doghead]

With a little searching(researching), you'd find a few dozen threads covering this simple modification.

A jumper works fine.

 

[blisters13]

I did a jumper 21 to 491 like Rattlecan6104 said but I used a spade connector pair so I could just reach under the dash and open the circuit if I wanted.

Some would say leave the lighting system as-is, but I'm not driving for Uncle Sugar with his infinite deep pockets and cadre of federally-empowered lawyers. I drive on public roads in a high-traffic, high-risk part of the U.S., so a few extra lights are a good thing in my mind.

Thanks to all for the great thread!

 

[Tlauden]

Wow, I didn't realize it was as easy as a jumper wire, I re-wired my front running lights into my master switch, in the future I want to wire all the lighting into the master switch. It will force lights on all the time as a safety measure. Can't be too safe in a big camo truck!!

 

[jw4x4]

Has anyone tried this with LED headlights? I tried to get the running lights to be on with the headlights (on my own) and was not successful. Tried it again @ Ga Rally with the help of some pretty smart minds but to no avail. We did not do anything to the switch, just tried jumper wires @ headlights/marker lights. Seemed like there was something built into the LED headlights that prevented the signals from flashing.

 

[juanprado]

jw4x4

On the m939 it is real easy. Open the box under the fender by the front light bracket/fixtures pull the side clearance light wire #489, install a y. replug the clearance light in to the Y. Find the original marker wire to the front lights #21 - abandon/unplug the wire from the harness. Tape up and seal. Plug the wire from the light fixture#21 into the Y.

Now the front marker lights will always be lit when the side clearance light is on just like every civilian vehicle out there. Easy mod

Requires 2 Y's, electrical tape and maybe 10-15 min per side as those boxes were not easy to remove as bolts were cruddy from rust/water and the lock nuts were a pain.

 

[sigo]

I have an adaptor from Erik's surplus installed and the front markers won't flash when the turn signals are activated. The rear flashes fine, but the front markers won't.

 

[Bill W]

I did the simple jumper that gringel mentioned on my first deuce ( pictured ) back in 1999 and its still works fine today, once I get my side running lights mounted on my current deuce I'll be doing the same thing to it, total cost was about 79cents

 

[jw4x4]

Juan- I already tried what you are suggesting, and the front signals will not flash. This may work for the stock incandescent lights, but not LED's. My headlights, front and rear signals are all LED. My flasher is the newer composite type. Everything works fine until the marker light mod is tried.

 

[rrrr]

When I upgraded to LED's on the front I had to get a new flasher unit from Erick's, now no issues. I did have Ericks cable mod already in my truck. I don't like splicing into 40 year old wiring if not needed. Everything works great. I have LED's all around on the truck.

 

[gringeltaube]

Jerry, in post #26 you mentioned having "tried jumper wires @ headlights/marker lights." ... which left me scratching my head, as what exactly was done.
Referred mod. really doesn't involve anything headlight- (or wire #16, instead) -related; nor does it affect the blinker function in any way, since wires #460 & #461 also remain untouched.

I'm following the circuits and just can't see how connecting #21 and #491 would make a difference - if you had LED's or incandescent lamps. I agree that you eventually needed a different flasher unit when changing over to LED's, but that doesn't have anything to with this modification.


G.

 

[juanprado]

I do have the led headlights. I do not have led front signal lights since I have the dual facing lolipops and that combo is bright. I do have the LED taillights in the rear and I do not have any issues. I do know the rear leds required an extra ground wire that the regular buckets do not have. Do the front require an extra wire? My extra ground was a short pigtail with a ring. Maybe try grounding in a different location.

I did have a grounding issue that drove me crazy when I installed the lolipops. One lolipop would never work but always tested fine on the other side when reversed to the other side. What I found is the 2 bolts that mounted the bucket to the frame which both are grounds btw where some exotic metal with the safety wire hole in the head. When I switched them to plain jane bolts problem went away and the ground for marker and flasher worked ok. Can't explain it but that is what I ran in to. Changed 2 buckets and lights for nothing on the same side.

I have seen that the trucklight flasher and others is different than the one seen at the surplus dealers. Maybe yours is newer than the older units but not the current LED specified one? I have seen 3 different flashers but don't know the specs or differences on them? Maybe get the part number and cage/mfr # and check their specs or website. They all mount the same and have the same pigtail but physically appear different. Sounds like a flasher problem to me but if the rear flash ok you got some gremlins there.....

Number 21 is a marker wire and not the flasher. 489 is all the clearance lights.

Does the clearance wire need a diode due to mixing led and incandescent bulbs? Maybe try using an led marker light from Lost/Bush in the classifieds?

Please let us know as you have a unique situation there.

 

[jw4x4]

G. - I mis-spoke about the mod. It did not have anything to do with the headlights. What we did (Mike, Recovry4x4 and me) was what Juan said in post 27. Ran a jumper wire from the side marker lights to the front signals. Did it on both sides at the same time, but the signal would still not flash. When I installed the front rear LED signals, they did not flash until I changed the second one (would not flash with just one replaced). Maybe if I get the pigtail adapter from Eriks it will work. But we still don't understand why we could not do it with a jumper wire.

 

[M35A2-AZ]

I just did the diode jumper from wire 491 to 16 and it worked great.
I Y'ed off wire #16 at the dimmer switch then ran it up and over to the lift light signal light.
Made a jumper Y setup with the diode housing.
Tested with all the lights and it work fine.

 

[Flyingvan911]

I installed the harness from Erik's. It does work as advertised. It allows the front park lights to come on with the headlights and all other light functions work the same. Park lights w/o headlights, blackout lights, all ok. It took about 5 minutes to install and can be removed if I want to for any reason. It costs a little bit but I recommend it. It is as heavy duty as it looks and can andle being twisted and bent if needed. The parklights are hard to see.

 

[tankie88]

I take it the jumper wire goes between the 2 numbered wires going into the plug that plugs into the back of the light switch??

 

[Cleveland Iron]

This should help.

 

[Lieutenant Dan]

Does anyone have a picture of actually what is done not just a schematic?