LED brake light mod - common ground?

[Andys]

I'm just trying to change my brake lights over for LEDs, but ran into a small problem.

I tested the 3 pin Jazz brake connector with a volt meter and it seems there is no common ground pin which my LED lights require. Instead, the voltage on the middle pin changes from GROUND to +12V when you hit the brakes ?!

So when the parking lights are on, Left is +12V and Middle is GROUND.
When you hit the brakes, Middle is +12V and Right is GROUND. Is this normal or is mine wired up incorrectly?! Its a pain because that'd mean I have to put in a relay to get the switching right for my Common Ground LED bulbs.

- Andrew

[Jus-10]

Mine has a common ground I think??? I never tested it as such but I had wired in the lower bulb in the original lights, and have also wired up the JDM LED lights and have had no probs...

There should be one wire for the parkers, one for the brakes and one for the earth....

[cameltree]

Jazz brake light bulb has two filaments in it when you look closely. There should be 2 pairs of wire connecting to the brake light bulb.

From memory that both +ve wires are on one side and the -ve wires are on another side. Both outer pins(the far left and the far right) are paired together(double check the bulb).

[Jus-10]

There are only 3 wires. The fact that it has 2 filaments doesn't mean that there is 2 pairs of wires.

[Andys]

Well, mine are uhh... chinese imitations of JDM jazz bulbs ;) The problem is that LED bulbs have to be wired the right way or they don't light up if the polarity is wrong. Normal filaments don't care what the polarity is, of course.

Anyway, I think I'll just keep the stock bulb as my parking lights, and use the LED bulb in the spare lower position (plus high-mount) as the brake lights.

- Andrew