Replacing backup light LED - soldered or solder-less connections?

I'm virtually certain you'd have to solder unless you buy the whole harness.  Did you look it up in the parts breakdown?

The tender harness, shown below, is marked unavailable.  So, you'd have to solder the LED to the one you have.  Are you sure the LED is bad?

I have an extra LED for this tender, but I'm not going to practice my soldering on this type of equipment.  I know someone who I think would do it for me.

The LED is bad; however, I think something else is bad, too.  I've had this engine for 7 years, and this will be the 5th time I've had the LED for the backup light replaced (in total, the 6th LED for the backup light).  By comparison, I've had a Lionel EM-1 for 16 years, and it's still on its first LED for the backup light.  Since the LED went out for the 3rd time, I've had the locomotive with both Lionel and a nationally known repair guy and have asked them to see if they can figure out why the LED goes out so frequently.  Both could not find anything wrong and just replaced the LED.  Any ideas?

Current is too high. Also could be AC and there is no diode protection for the reverse cycle. Stuff like that. You would have to measure the current and look at the source of the voltage, AC or DC.

Something is clearly wrong as Chuck states, the LED should last the life of the locomotive.  I'm 100% sure I could figure out what is wrong, but obviously only on the bench.

My "fix" without seeing it would be to graft a series diode and resistor in series with the LED, I'd probably go for a 470 ohm 1/4w resistor and a 1N4003 diode, common parts you can get anywhere.  Since I can't imagine you have more than 18V running around anywhere, the resistor should limit the half-wave current properly, and the diode will protect against reverse voltage spikes.