# Wiring an E-unit



## daveh219 (Sep 16, 2012)

I finally did a complete re-hab/overhaul on an AF e-unit. Getting the fingers out was not a problem, getting the rotating wheel out and polished up - not a problem...BUT when I went to reassemble everything I got to wondering if it would be better to cut a 6 inch length of wire and then solder it too the finger BEFORE putting the finger back on the u-unit. Once back together I could cut the wires to the correct length for the plug.

PS...the name of the "wheel" escapes me

Thoughts???:


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## AmFlyer (Mar 16, 2012)

If you are repairing a 4 or 5 wire steam engine with the tender mounted reverse unit I do not see how that would work. The harness is continuous from the solder connections in the tender to the plug that connects to the engine. If you are repairing a two position engine mounted reverse unit, A, you have my sympathy and B, if it helps by all means do it.
Maybe someone else here has better experience than I do.


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## AmFlyer (Mar 16, 2012)

In my reply above I neglected diesel's. There are so many internal variations such as single or two motor, individual wires, harness wiring or rainbow wire that it is hard to reply. I suggest if it works, it is ok. The one thing to be aware of is to not put a solder joint where the wire needs to flex. Solder can travel and harden a good distance along stranded wire.


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## flyernut (Oct 31, 2010)

That little wheel is called a reversing drum...I use a cloth-covered 4-wire harness when I re-build my units, so it's hard to solder a single wire to the finger. I believe the top fingers need to be in position to do the soldering, the lower fingers I do off the unit.


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## daveh219 (Sep 16, 2012)

Flyer...why do the lower fingers have to be on prior to soldering...


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## flyernut (Oct 31, 2010)

The lower fingers do not have to be on before soldering, but the upper fingers have to be. That's because there's 2 wires that have to do to the same finger. There's a short wire coming from the solenoid, and a wire coming from the harness that go to one of the fingers. It's just easier, in my opinion.


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