Bachmann class 150 270 tail lights permanently on with DC and DDC

[muddy water]

I picked up a second hand Bachmann class 150 270 in Regional Railways livery. This is the one with the solid motor block in the powered car. 
Both on DC and DCC it has the red tail lights on the power car and will not switch to the white/yellow head lamps.

I have swapped the dummy car with another set and that works ok, switching lights with direction.

 

The circuit board have no visible damage.

Testing with a meter on the terminals to the LED panel at the end of the main pcb show the voltage is not reversed when the track supply is reversed.

 

Any ideas?

Edited February 18, 2021 by muddy water

[muddy water]

Still not found the answer. Any ideas?

[smokebox]

13 minutes ago, Graham1960 said:

As far as I am aware you can't operate anything DCC with a DC system. If the train was fitted with DCC control and then you (or somebody else) will have caused damage if you then applied DC voltage to it. 

Quite the contrary.  You CAN normally run DCC locos on dc but you should not run dc locos on DCC.

[muddy water]

Anyone have a circuit diagram for the class 150? As I think a transistor has been shorted out, hence the permanent feed for the red lights. Not allowing the switch to white when the voltage is reversed on dc power. ( lets get it working on dc before worrying about DCC)

[muddy water]

any ideas??