Wiring diagram for 12 pin trailer plug on m923?

[Cobra2401]

Hi, was wondering if anyone has a wiring diagram for the 12 pin trailer plug on the back of the truck. I wanna jump off that and run a 7 way flat style tv plug. I would appreciate anything. Thanks

 

[steelandcanvas]

Is this what you need?

 

[Cobra2401]

Yes, perfect. Thanks. Also, was wondering on the back of the truck plug there's a wire that's capped off, that doesn't go to anything. There's a metal tag on it with the number 3 on it. Any ideas what it's for? Thanks again.

 

[FP1201]

Couple of the wires in the plug aren't always used. This is a good source: http://xm381.com/xm381/Civi_Trailer_Lights.html Ironically when I went to wire my trailer & converter to the truck, the plug was upside down.

 

[Cobra2401]

Those converters are nice but can't spend that much on one right now. I was gonna just either buy 24v bulbs and switch them out on the trailer. Or buy a set of emergency trailer/tow magnetic lights.

 

[Cobra2401]

"FP1201" I see your in Fort Drum, NY. That's where I bought one of my m923's. My dads came out of Indianapolis,IN. I live 20 minutes west of buffalo, ny. Was trying to find someone close by me so I can talk to them about these trucks and pick his/her brain. Plus it would be nice to meet someone local that also enjoys these trucks. My neighbor down the road from me has a old military jeep that he mounted a 50 cal. On it lol.

 

[steelandcanvas]

Yes, perfect. Thanks. Also, was wondering on the back of the truck plug there's a wire that's capped off, that doesn't go to anything. There's a metal tag on it with the number 3 on it. Any ideas what it's for? Thanks again.

Glad I could help. Are you sure it's a #3 and not a #37? #37 is a constant hot that seems to be only connected to the trailer plug on tractor variants. It may be capped off for the cargo truck variant. I am going to look at mine tomorrow.

 

[Cobra2401]

Yeah, it's definitely a #3. Ill take a look today and see what location it comes out of. Maybe they wire all the plugs the same and then put different bodies on the back of the trucks. For example tractor, cargo,etc. thanks again for the help. Much appreciated

 

[FP1201]

"FP1201" I see your in Fort Drum, NY. That's where I bought one of my m923's. My dads came out of Indianapolis,IN. I live 20 minutes west of buffalo, ny. Was trying to find someone close by me so I can talk to them about these trucks and pick his/her brain. Plus it would be nice to meet someone local that also enjoys these trucks. My neighbor down the road from me has a old military jeep that he mounted a 50 cal. On it lol.

You're welcome to pick my brain, but the pick'ns are slim. As for the trailer light converters: they are nice, properly though out, and well made. That said, one could easily make their own; all you need is a 24 volt step-down thansformer/converter

 

[steelandcanvas]

...all you need is a 24 volt step-down transformer/converter

I agree with you, the trailer converters are very spendy. However, step-down transformers only work with AC Current. You can use a resistor in the circuit as long as the load is consistent, install a 24 to 12 VDC converter, or install a separate 12 VDC alternator and battery for an independent 12 VDC system. If you need electric brakes on the trailer, the last 2 suggestions are the ways to go.

 

[FP1201]

I agree with you, the trailer converters are very spendy. However, step-down transformers only work with AC Current. You can use a resistor in the circuit as long as the load is consistent, install a 24 to 12 VDC converter, or install a separate 12 VDC alternator and battery for an independent 12 VDC system. If you need electric brakes on the trailer, the last 2 suggestions are the ways to go.

Actually, a Marine Supply store or Car Audio shop (forget Best Buy or Box stores that sell audio) and they can order you an inverter. Pyle has one with modified sine wave, 24VDC in 12VDC out 480 watts (www.pyleaudio.com) Couple 24V relays (doesn't really matter the design or style, but I wouldn't use one the size of a Starter relay) 24v from the Park, Left, and Right turn signals: the turn signals trigger the relays to allow 12V power through them. I used an ammo can for everything, I'll have to post pictures, maybe even order for re-sale some of the inverters.

 

[steelandcanvas]

I'm confused. You spoke of an inverter, which makes AC out of DC. A modified sine wave is an AC voltage. A converter steps up or down DC current, a transformer steps up or down AC current. I'm not trying to be a butt-head, I just want to be on the same page. I see no reason for AC on the vehicle in this instance. Any small relay that will handle the current of what you are trying to switch is sufficient, I'd get a unit with the contacts rated for at least 50% more current than what you need. I plan on building a relay box like yours someday and eventually get set up to tow an RV. I'd like to add the 12 Volt alternator and battery, for an independent 12 Volt system. This way the RV will get it's house batteries charged from the Deuce, I'll have electric brakes for the RV, and I'll always have good batteries to start the engine with. Post your pix, I want to see what you came up with.

 

[Cobra2401]

Thanks. I've been looking at the different converters

 

[glassk]

I'm confused. You spoke of an inverter, which makes AC out of DC. A modified sine wave is an AC voltage. A converter steps up or down DC current, a transformer steps up or down AC current. I'm not trying to be a butt-head, I just want to be on the same page. I see no reason for AC on the vehicle in this instance. Any small relay that will handle the current of what you are trying to switch is sufficient, I'd get a unit with the contacts rated for at least 50% more current than what you need. I plan on building a relay box like yours someday and eventually get set up to tow an RV. I'd like to add the 12 Volt alternator and battery, for an independent 12 Volt system. This way the RV will get it's house batteries charged from the Deuce, I'll have electric brakes for the RV, and I'll always have good batteries to start the engine with. Post your pix, I want to see what you came up with.

Thank you for the wiring photos posted, I needed a copy,


I also was wondering about the sine wave,

the unit he listed says this on the pyle site,

For Use in 24 Volt Vehicles Trucks, RV, Buses, Etc. Allows installation of 12 Volt Items Such as Car Stereo's, CB Radio's, Fog Lights, Etc.

 

[Cobra2401]

I'm sorry, I was talking about the converters that drop 24v dc to 12v dc

 

[glassk]

I'm sorry, I was talking about the converters that drop 24v dc to 12v dc

Look around on this site, they have lots of deals,

http://www.mpja.com/24V-Input-12V-38A-DC-to-DC-Converter/productinfo/18132%20PS/

[h=1]24V Input 12V, 3.8A DC to DC Converter $4.95[/h]The modifed sine output would help if laptop or audio equipment, the relays with this 3.8Amp should work lights ,

 

[FP1201]

I'm confused. You spoke of an inverter, which makes AC out of DC. A modified sine wave is an AC voltage. A converter steps up or down DC current, a transformer steps up or down AC current. I'm not trying to be a butt-head, I just want to be on the same page. I see no reason for AC on the vehicle in this instance. Any small relay that will handle the current of what you are trying to switch is sufficient, I'd get a unit with the contacts rated for at least 50% more current than what you need. I plan on building a relay box like yours someday and eventually get set up to tow an RV. I'd like to add the 12 Volt alternator and battery, for an independent 12 Volt system. This way the RV will get it's house batteries charged from the Deuce, I'll have electric brakes for the RV, and I'll always have good batteries to start the engine with. Post your pix, I want to see what you came up with.

I don't know what exactly to call it; bottom line is you put 24 volts in and get 12 volt out. Knowing why a plane flies isn't as important as knowing it does. The "Modified sine wave" comes off the manufacturers packaging; there is this thing with "dirty electricity" that's hard on electronics and appliances, for the most part the lights on a trailer will function irrespective, however someone will get the idea of running a lead for a cigarette lighter plug for there GPS, smart-phone, DVD player, etc. where it might be an issue. (seems most of these newer electronics just don't play nice with spikes/dips in voltage & amperage)

 

[FP1201]

That's 24 volts Direct Current in and 12 volts DC out. Another consideration: there are LED lighting manufacturers that make Stop/Tail/Turn as well as marker and tag lights that will work on voltage ranging from ~6VDC to 24, maybe even as much as 36VDC. might be a cheaper option, certainly easier.

 

[Cobra2401]

Yeah, that site does have good prices on stuff. Thanks. Also I was thinking of just changing all the bulbs over, but it would be nice to have the flexibility of a adapter box for use on any trailer.

 

[mikew]

I've built a few 24v to 12v trailer lighting converters in my day, and here's what I've learned....

If you're pulling a trailer with your military truck and that trailer never gets pulled by a 12 volt vehicle, swapping out the bulbs is the cheapest route.

The nomenclature for converters/inverters is kind of confusing;

A "DC-DC Converter" changes one DC voltage into another DC voltage, like 24 volts to 12 volts, or maybe 12 volts to 24 volts, or any other combination you can think of.

A "DC Inverter" turns DC voltage into AC voltage, like 24 volts DC to 110 volts AC. Inverters generally come in two types, "Sine Wave" or "Modified Sine Wave". "Sine wave" puts out a true 110 volt AC sine wave whereas "modified sine wave" puts out a stair-stepped looking waveform. Modified sine wave is typically less expensive but some kinds of equipment (things with electric motors) may not like modified sine wave.

A typical 12 volt "1157" light bulb used for turn, stop and tail lights requires a little over 2 amps for the stop and turn filament and a little over 1/2 amp for the tail filament, call it 3 amps per bulb, so you'll need at least 6 amps per trailer if there aren't any other lights on the trailer. One thing to keep in mind, the "inrush" current (incandescent light bulbs draw more power when the filament is cold, i.e. not illuminated, than when making light) is almost 10 times the running current. That 10x current last for less than 1/10 of a second but can be enough to shutdown some DC-DC converters.

When purchasing a DC-DC converter you should determine what happens if the output gets shorted (will the converter catch fire or shut down if you have a chafed wire on your trailer that grounds out when you hit bumps) and what happens when it gets wet (is it waterproof, a consideration when dealing with military vehicles).

Sourcing components is the hard part of building a proper trailer light converter, here is a schematic that shows how to wire everything up:

http://www.xm381.com/xm381/Civi_Trailer_Lights_files/Civi Light Schematic - Standard.png