You program the units simultaneously under the same ID for both so they operate as one unit together.

I've never done a "lash up" with legacy, only TMCC but with an F3 AB and an add on A unit I have, they have their own ID's.  I created a lash up so that they operated together with the lighting woking correctly.  When creating a lash up, you can specify the direction of the unit that is running in reverse so the lighting works correctly.  Hope this helps.

Tony

The item number would help. If you 'Lashed" them up into a Train it will know which unit is forward and which is facing reverse. (We have only one set where the rear unit was set up by Lionel to begin in reverse.)

These were designed to be run a s a train with each unit having its own control number.  I you have Legacy system, the manual will describe how to do this and makes it very easy.  The trailing A should be set up as second engine and in reverse direction.  Now that I have five or six AA units, I have started suing the leading unit ID number as the Train number.  using the same number makes remembering correct Train number a lot easier.

If you are using TMCC, you still need to set it us as a train to make couplers and lights work as designed.

Happy railroading,

Don

Well, I tried giving them the same ID. Then changed back.

The cab lights of both units are now flashing continuously.  This happens as soon a track power is applied . .  to both units. Continues when CAB2 controller is powered on. Smoke is turned off with the hard switches, BTW although AFAICT, both smoke units are fine. Fans run. Exhaust from the stacks seem warm as if both heaters are OK. But I turned both units off with the switches. The flashing persists. All other operation seems fine. There is no "code" being flashed . . . just a continuous, monotonous, maddening flashing.

The expression "what have I done now?" comes to mind.

How can I turn those lights off?

Terry Danks posted:

Well, I tried giving them the same ID. Then changed back.

The cab lights of both units are now flashing continuously.  This happens as soon a track power is applied . .  to both units. Continues when CAB2 controller is powered on. Smoke is turned off with the hard switches, BTW although AFAICT, both smoke units are fine. Fans run. Exhaust from the stacks seem warm as if both heaters are OK. But I turned both units off with the switches. The flashing persists. All other operation seems fine. There is no "code" being flashed . . . just a continuous, monotonous, maddening flashing.

The expression "what have I done now?" comes to mind.

How can I turn those lights off?

A continuous blinking could be "Code 1" motor driver issue.  Does the powered unit move?  That doesn't explain the dummy unit though.

Is it possible you just need to re-assign the ID again to "reset" them?

You never did give us the 6-number either.  It might help.

Sorry. It's

6-34645

CN 9000/9002 A-A

It runs fine. Seems fine in every respect except both units have a continuously blinking interior light.

Thanks

Did you follow the instructions on page 21 of the manual to do a feature reset?

1. Slide the Command reverse unit switch on your locomotives to the PGM position. See pages 13, and 36 for the location of the Command Reverse Unit switch on each unit.
Work with only one locomotive at a time.
2. Plug in and connect your Command Base.
3. Place your locomotive on the track, then power up the track.
4. Press ENG and enter the locomotive’s ID#.
5. Press SET.
6. Press ENG and enter the locomotive’s ID# again.
7. Press AUX1.
8. Enter 2 for this particular locomotive.
9. Turn off track power and wait ten seconds.
10. Slide the Command reverse unit switch back to the RUN position.
Repeat these steps for each locomotive.
At this point, your locomotive has been reset. Restore power to the track and operate the locomotive as usual. Be sure to use the ID# entered in Step 4.
21

I also believe that this vintage Legacy F3 set requires them to be in a "lashup" for the directional lights to operate correctly.  I have the Santa Fe version of this locomotive produced around the same time and I must make them in a (lashup) to have the lights correctly respond.

The p21 procedure for both units worked. Thanks to all for the help! All seems well now!

I'll leave the lashup for another day.