TMCC feature codes

FfffredddOGR Forum Member

Been discussed a lot and never clearly answered.
Did two ERR diesel upgrades.
One was a K-line S-2 with one light upgraded using a DC commander with electrocouplers, cab lights and front and rear lights.

The other was an older MPC SW-2 using an AC Commander with just lights. Front, rear and cab.
In both installations:
feature code 5 gives me flashing cab light. (Strobe)
Feature code 6 gives me Cab light in reverse only.
feature code 8 (normally smoke) gives me Cab light in both forward and reverse with off on.

My question is: is this normal for the code 6 feature to not have cab light in forward?

2/25/143:02 PM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Are you using an LED? Try reversing the polarity. I believe feature code 6 reverses the polarity of the output for direction.

2/25/144:47 PM

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FfffredddOGR Forum Member

Hi John,
Won't that just make the cab like come on in forward instead of reverse?
It works on the code 5 Strobe setting and works on the code 8 smoke setting. it only works as a cab light in reverse on the code 6 setting.

I will reverse the polarity but if it now only works in forward that still does not answer my original question.

2/25/145:12 PM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Yes, if you're using an LED. I just use the smoke setting for this issue, easy fix.

If you really must use the CAB setting, put a bridge rectifier across the light outputs and feed the LED from that, it'll make sure that you always have the correct polarity.

The CAB setting was used for directional markers as well, hence the reversal of the polarity.

2/25/145:19 PM

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FfffredddOGR Forum Member

Thanks John,
Makes sense now. Designed for an incandescent cab and LED directional markers.
I have been using the smoke feature.
Will continue. Less hassle.
Funny thing is I used A yellow LED for the cab and experimented with different Resister's to make you look like a dim incandescent.
I didn't wanted to overpower my super bright white backup light.

2/25/145:44 PM

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gunrunnerjohnOGR Forum Member SUPPORTING MEMBERDIGITAL SUBSCRIBER

Don't ask me how I first found out about the cab light polarity feature.