Use a piece of wire to determine which contacts on the bulb are the low & high contacts by holding the wire to each contact while touching the base to ground. Then use a test light to determine which socket contact is which. I suspect Baldy is correct about you being 180º out of phase on your wiring.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.