m872 info needed

The running lights on my m872 keep overloading the resistor and blowing it out. The resistor that was in the trailer when I got it was blown out when I hooked up to it. I replaced it with a exact match. I checked for a short with the meter and all the wiring shows to be good. Can someone tell me what size resistor is sposed to be in there for this just so I can make sure I have the right one? Any other suggestions are welcome to!

Are you sure that the one that was in it when you got it was the correct resistor? Isn't the M872 a 24v trailer? Why is there a resistor anywhere? What are you towing it with? Please describe the electrical system, what voltage bulbs are in it, etc. Happy to help, but need more info.
Jim

Towing with a m818. The trailer is set up to where you can hook it up to a civilian 12v truck or a military 24v truck. All the lights on my trailer or 12 volt except for the blackout lights. Left and right turn signal each have their own resistor and work fine.

Best source of info right here and absolutely free.

I am SURE the -P tm would have the correct part listed, the -20 should have the wireing layout

I type SLOW

Where did you get the resistor?

Check the bulbs to make sure they are the correct candle power.

The second thing to look for is a short in the wiring harness.

I checked for a short- as stated in first post.
I dont know if the lights are right. Thay do match. Thay look like the standard 18 wheeler type bulbs and housings that I have dealt with in the past.

Right now the lights are pulling 4amps at 24v. So im thanking with the alternator charging figure for 28 volts. Amps x volt = watts I round up a bit. So i come up with a 120watt resistor.

Sound right?

I read through the TM and found nothing about the size(watt) and no part number for the resistor.

Are there only one set of lights? if so, the 12v connection will run right to them, and the 24v connection has the resister. I recommend putting LED lights on the trailer. Not only are they brighter and last longer, they are omnivolt, meaning that you can run 12v or 24v and they work the same. I put them on my tanker and M270, so I could pull them with my MV stuff or the civi tractor I used to have.

Draws way less amps too. The tanker had 11 markers and the tail lamps, sometimes the 3 lever switch in the XM818 would trip drawing all those when they were incandescent.

Or, you can find one of these-

Yea i was thanking about LEDs too. That may be the way i end up going. But leds just sound expensive. I would like to get the lights to work the way that are supposed to.

tiny110 said:

Yea i was thanking about LEDs too. That may be the way i end up going. But leds just sound expensive. I would like to get the lights to work the way that are supposed to.

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It' a expensive hobby . You can fix it right the first time or cobble it and let it nickel and dime you to death . I would rather fix it right the first time instead of trying to fix it again in the middle of the night in the middle of nowhere . I figure my time is worth more than to spend it fixing the same problem over and over . And the old style lights are high maitainence lights.

I've had 0 issues with the lights on my trailers since swapping to the LEDs.

And I've probably put hundreds if not thousands of hours on them.

i ordered the right size resistor to run the lights. $17 with shipping. so i guess i will give that a try. if that dont work i guess i will go LED. i will let yall know how it works out.