[DanEC]

Originally Posted by patrickt

Dan, why don't you buy two of these and just plug the bare wires in to the plugs on the back of the car? Yes, I know it's essentially throwing away $15, but it would make diagnostics easier.

Amazon.com: Auto Car Plastic Water Resist 1157 Rear Brake Light Socket: Automotive

Patrick - actually I'm a little ahead of you. I bought one last week and I think I will go back and get another one. I bought it to hook an additional incandescient bulb up to the parking light circuit to see if the extra load would straighten everything out (it didn't). My latest theory - and I don't know if it will hold water - is some terminal incompatibility between the tail light socket contacts and the bulb contacts.

I don't know why, but if you check you'll find that the socket contacts and the bulb contacts are only aligned when sliding the bulb pins down the straight grooves. Once the bulb is twisted to seat it, they are no longer in alignment. It's like the socket contacts are at 6 and 12 o'clock and the bulb contacts will be at 1 and 7 o'clock. Seems to work OK in most instances but the LED bulbs don't have a nice round contact point on them - it's more of a rectangular contact. I think there is something about them and my light sockets that is shorting across the terminals.

Both the aftermarket 1157 bulb socket and the ERA tail light socket are oriented the same but the tail light sockets do have rather large, button contacts in their bottom.

For instance with parking lights on - if I slide the superbrights into the socket they light up - as soon as I twist them clockwise to lock them - they go dead.

So, I'm going to get another 1157 accessory socket and wire them up to my lighting leads and see what happens then. I have a suspicion they will work - but my record so far is not too good.