No headlights, turn signals, but guages work...

[Blacksunshyne]

I bought a 1972 M109a3 at a local auction about 6 months ago. When I bought it the wiring and lights did not work and were in terrible shape. I have been using it on the farm for the past months, but want to get it road worthy. So, I bought and installed new front and rear wiring harnesses along with LED tail lights and LED front marker/turn signals.

This past weekend I installed both new wiring harnesses and all new head lights, tail lights, etc. I also installed new 3 lever switch and turn signal switch. Truck will start easily, low air buzzer works, all guages work but headlights nor signal lights will work. The truck currently has no stop lamp switch, but I will be ordering an air switch to put on the airpack. I don't think that the missing stop light switch at the airpack is causing my problems...is it?

Anyone have any ideas of what to try next, with an almost totally "new" electrical system I would think this would work. Any ideas and help is greatly appreciated. I have been searching all weekend on here as well and have not come up with anything to help my situation.

Could it be as simple as bad battery cells?

 

[sandcobra164]

Not sure on the headlights but I've had trouble out of my flasher unit before. A cannon plug with 3 wires goes into it and it sits on the driver's side inner fender. When my turn signals stopped working, that was the problem. I switched out the headlight switch, the turn signal switch and still had only a solid turn signal, ie' not flashing. One thing that comes to mind is the fact that the LED turn signals may not pull enough juice to cycle the flasher. I do have LED headlights and they worked fine with either switch. When my flasher failed, it did so while it was running the 4 way flashers after I moved the truck across the road as was mowing the grass that grew under it. It was left like that for maybe 20 or 30 minutes.

 

[3dAngus]

Been doing a bit of research on this one today. Probably a bad ground.

 

[Blacksunshyne]

Not sure on the headlights but I've had trouble out of my flasher unit before. A cannon plug with 3 wires goes into it and it sits on the driver's side inner fender. When my turn signals stopped working, that was the problem. I switched out the headlight switch, the turn signal switch and still had only a solid turn signal, ie' not flashing. One thing that comes to mind is the fact that the LED turn signals may not pull enough juice to cycle the flasher. I do have LED headlights and they worked fine with either switch. When my flasher failed, it did so while it was running the 4 way flashers after I moved the truck across the road as was mowing the grass that grew under it. It was left like that for maybe 20 or 30 minutes.

It may be a bad flasher relay. I ordered my parts thru C&C Equipment and they told me the relay should work fine with the LEDs, but it could be a bad unit altogether. The whole electrical system was in pretty poor shape. It would not explain the headlights tho, which are regualr bulbs. I will keep looking into this tho...

Been doing a bit of research on this one today. Probably a bad ground.

That was my thought as well, I guess the next order of business is to take off all ground connections, clean and re- tighten.

I guess I was just hoping there was some little something I missed, or a quick fix. As I am finding out there are rarely any quick fixes with these trucks.

 

[dabtl]

I find that most light problems on my deuces have been caused by bad grounds. Once it was a wire pulled loose from a splice and once it was a flasher.

Just get an ohm meter, make a long extension and start checking for completed circuits. Grainger has the inside/outside star washers quite low priced.

 

[gimpyrobb]

The flasher units are not effected by the led lights. I would suspect ground issues too.

 

[Blacksunshyne]

Just wanted to follow up on this. We finally traced it down to a bad brand new 3 lever switch. I guess it is rare, but it was bad right out of the box. Another switch and all lights work.

Now the passanger side headlight keeps blowing. I mean with in five minutes of installing a new one. Have been through 2 now. I at first thought it was a bad head light (also brand new) but the second new one blew just as fast. Looks as though it burned up, turned the lens a blueish color. My next guess is a bad ground. I guess I will start at the headlight and clean the grounds. Any other ideas are always welcome!!

 

[cattlerepairman]

Time for some voodoo.
Based on "this works for me, no guarantees given, batteries not included" I would like to add that, if your turn indicators seemingly stopped working, put the left signals on with the engine running. Take the green plastic lamp cover off the turn indicator light and check if you can see the lamp glowing very dimly. I find that the only stalk position the lamp glows in is left turn. You can try others, including the 4 ways. who knows.

If you get the dim, almost invisible glow of the indicator lamp, after about 10-20 mins of having been left switched on, the flashers may spontaneously come on and work from there on.

It may still mean your flasher unit is going out, but at least you can get some function back. I discovered this by accident and it has worked on two different trucks.

 

[greg2560]

You are putting in 24 volt lights right... not 12 volt. Is it really bright then goes out?? If you had a bad ground the light would be dim or no light at all

 

[Blacksunshyne]

Time for some voodoo.
Based on "this works for me, no guarantees given, batteries not included" I would like to add that, if your turn indicators seemingly stopped working, put the left signals on with the engine running. Take the green plastic lamp cover off the turn indicator light and check if you can see the lamp glowing very dimly. I find that the only stalk position the lamp glows in is left turn. You can try others, including the 4 ways. who knows.

If you get the dim, almost invisible glow of the indicator lamp, after about 10-20 mins of having been left switched on, the flashers may spontaneously come on and work from there on.

It may still mean your flasher unit is going out, but at least you can get some function back. I discovered this by accident and it has worked on two different trucks.

The flashers and all hazards are now working great (they are all LEDs). It is only the passenger side headlight that keeps burning out quickly.

You are putting in 24 volt lights right... not 12 volt. Is it really bright then goes out?? If you had a bad ground the light would be dim or no light at all

They are 24 volt headlights for a duece. Both headlights will burn as you would expect for a few minutes then the passenger side light burns up and fills the lens with a blueish haze.

I have little electrical knowledge so even elementary help is very appreciated!

 

[jimmcld]

Check your mounting bracket on the headlight. You may be cracking the bulb when you tighten down the mounting screws.

 

[Blacksunshyne]

Check your mounting bracket on the headlight. You may be cracking the bulb when you tighten down the mounting screws.

I had never thought of that. Just to clarify, you think I may be overtightening the three screws the hold the headlight in the housing? Would this be pushing the back of the headlight into the housing making the bulb crack?

 

[jimmcld]

I had never thought of that. Just to clarify, you think I may be overtightening the three screws the hold the headlight in the housing? Would this be pushing the back of the headlight into the housing making the bulb crack?

I don't think you could push the bulb back into the housing. However, I know that you can crack the bulb by tightening the screws too tight.

 

[Blacksunshyne]

I don't think you could push the bulb back into the housing. However, I know that you can crack the bulb by tightening the screws too tight.

I had never thought about that, it is something I will look into.

While we are on the subject would LED headlights be effected as badly? They are expensive, so I would hate to blow out one of those if it does turn out to be an electical problem. Would the LEDs be as sensitive to these problems?

 

[Blacksunshyne]

Continuing to think on this...This past time the headlamp burned out it was after I tested the hi/lo dimmer floor switch.

Could it be a faulty dimmer switch that is making this happen? To only one headight?

 

[Deuce007]

Because turn signals was a part of this thread, I was wondering what the little slide is on the blinker handle.

 

[Deuce007]

Continuing to think on this...This past time the headlamp burned out it was after I tested the hi/lo dimmer floor switch.

I would try clicking the dimmer switch because on one of our trucks hit the dimmer switch once and the lights turn on bright, hit it again and there are no lights at all.

 

[Blacksunshyne]

Because turn signals was a part of this thread, I was wondering what the little slide is on the blinker handle.

THe slide on the turn signal is for the hazards or four way flashers. Pull it out and push the turn signal all the way up to turn them on.

Continuing to think on this...This past time the headlamp burned out it was after I tested the hi/lo dimmer floor switch.

I would try clicking the dimmer switch because on one of our trucks hit the dimmer switch once and the lights turn on bright, hit it again and there are no lights at all.

The headlight is clearly burnt out, the filament is burned up and a blue smoke haze has filled the lens, and the drivers side still works so I don't think that is the case here.

 

[houdel]

I do have LED headlights and they worked fine with either switch.

LED Headlights???

 

[Blacksunshyne]

Ok, so I have installed a brand new dimmer switch and another headlight with the same results the passenger side headlight fogs up the glass with a blue haze and then burns out in about 4 or 5 minutes. The drivers side headlight has been fine this whole time. I am running out of ideas to try to fix this problem, anyone have anything else to check?