Lighting woes….

[LIRR]

I need help with lighting CVs.

I have 4 Atlas diesels. All have the same LOKSOUND decoder as far as I know. One consist is a pair of SD24s. A second consist is a pair of S4s. When I run the S4s the headlight command will turn on the light of whichever unit I select. When I run the SD24s both lights (one each unit) come on when I select either unit.

I’ve made no changes to the lighting. Actually I cannot figure out where to start when looking at the LOKSOUND manual. Which CVs are involved?

I would think all units would have been configured the same at the factory. 

[peteski]

We need some clarification.  What type of consists are they running in?  Is it advanced consist (CV19 is used for the address)? What DCC system are you using?

[LIRR]

Of course I should have included this info..

Wireless NCE procab. Advanced consist, CV19 is not used….system assigns consist number when i set it up…i select by unit address.

[peteski]

Of course I should have included this info..

Wireless NCE procab. Advanced consist, CV19 is not used….system assigns consist number when i set it up…i select by unit address.

Well, NCE does use CV19 behind the scenes.  That is how that works.  The system allows you to address the advanced consist by the original locomotive addresses (front and rear).

From https://dccwiki.com/Multiple_Unit_Consisting/NCE_Consisting_Notes

NCE employs a hybrid version of Advanced Consisting, which they call Intelligent Consisting. Motor commands are sent to the consist address, while function commands are addressed to the lead locomotive. The Consist Address is stored in CV19. The consist addresses range from 1 to 127 using a short address [1]. The command station assigns consist addresses starting at 127.

The command station generates a table that references the locomotive address to the assigned advanced consist address. This constructs an alias of the locomotive address for controlling the assigned consist address.

I'm not up on dealing with how NCE works ( I only run single locos with my Power Cab), but  I suspect you will might have to tweak CV20 and 21 to get the headlights to do what you want.  I assume that each S4 has a unique address, and you definitely set it up as advanced consist. Maybe start by deleting and recreating the S4 consist?