Output Short

[Michael]

Hello Group:

This is my first install of an LM-2S module. Previously I have installed an LM-2 module successfully (1 light). This install is in a non-ready DCC loco. The loco will run fine in either direction. The sounds will work. I receive the message "OK - No Faults" until I attempt to use one of the light buttons, then the message changes to "Output Short" - "Short circuit detected in output. Check for wiring problems."  I took the loco to my LHS and they installed a DCC decoder. Everything worked fine, including the light functions (3 lights - 2 LEDs with resistors) with the DCC decoder.   
I have checked the various forums, and instructions found on this website, but did not come across anyone having this similar problem.
Does anyone have a suggestion as to what I need to do?

Mike Sullivan

[KPack]

There is definitely a short somewhere if you are getting that message.  I've had it once but I honestly don't remember the exact circumstances.  I do know that I found the problem eventually and got it resolved. 

More info is needed to see how we can help.  What light output specifically is causing the problem?  Do the other light outputs work?  You mentioned there were 3 lights, but only two LEDs....what do you mean by that?  What locomotive are we talking about?

-Kevin

[Michael]

I am not sure what light output is causing the problem, as none of the lights will work. Actually there are a total 8 lights, however, 2 of the lights are used for the interior, there is 1 headlight, 1 taillight, and 4 marker lights (for the total of 8 ). The marker lights are LEDs. with resistors. The other lights are regular incandescents. So, I have the 2 interior lights wired for the 1st function, the taillight plus 2 marker lights for the 2nd function, and the headlight and 2 marker lights of the 3rd function. I model trolley cars, so this isn't a typical locomotive.  The trolley car is metal. The floor and roof are wood.

Mike

[William Brillinger]

I wonder if there is a short in the LM on one of the light functions.
Do you have another LM to try?

[Michael]

Yes, let me try another one I have, and I'll let you know the results.

[Michael]

I tried the other LM-2 I had on hand, and received the same message - Output Short.

[nodcc4me]

Try disconnecting the outputs, one at a time and try the other lights. If only one of the outputs is causing the problem, that will narrow it down.

[G8B4Life]

This is a long shot, but worth mentioning. Are you using the 6 pin harness for lights as well as the 9 pin? if so I'm guessing the problem could be there as you mentioned that when the LHS fitted a DCC decoder the lights worked, and the DCC decoder wouldn't have been able to have the 6 pin harness plugged into it.

If you try disconnecting the 6 pin harness from the LM do the lights connected to the 9 pin work?

Your best bet is to draw yourself a wiring diagram (like what's in the LM instructions) of what lights are connected to what wires on each harness in your install (draw as you trace the wiring) and go from there. You may even spot the problem while you are making the diagram.

- Tim