I checked the polarity of the purple wire with a test lamp. Wire to ground lights up the lamp so reverse polarity does not seem to be the problem. Will report back after further experimentation.
John
Don't wish to be critical, but just for sake of correctness: A test lamp between two terminals will always light regardless of polarity.
As Sewin suggested earlier, the only sure way is to use a multimeter or DC moving coil voltmeter, which will show a negative reading or the case of analoque instrument, the pointer will go in reverse.
