Was wondering if this has happened to anyone before. When my switch is in low beam position. The low and high beam wires have power to them. When you switch to high beam only the low beam has power to it. And when you pull back on the stalk only low beam has power to it. It's like it's reversed? Weird. Anyone have any wiring diagrams? It's really bugging me.

Yeah the headlamps share common power and are grounded through the hi-lo switch.

You'll have 12v on the wire for the filament that isn't lit, because that wire is not grounded at that time.

Gets more fun when you have fog lamps due to the wiring for the fog lamp relay.

Ok but I wired in HID bulbs. With the JDM projector lights. And when in low beam. The high beam bulb is on with the low beam hid as well. When I push the stalk forward into high beam position. Just the low beam stays on and high beam shuts off.

You must have them wired wrong.

Did you get real HIDs or the fake "HID style" halogens?

 

Real HID lamps need a ballast module to work properly and that's going to need its own separate wiring to function correctly.

Definitely wired correctly. Ballasts, relay harness. Everything.

 

Besides that. Even if I remove everything. And just test for power at the factory socket. It does what I describe. Low beam position. Power on both high and low beam wire. High beam position power only on low beam wire.

Right side

Red: high beam ground

Black/yellow: 12v supply

Yellow/blue: low beam ground

 

Left side

Red: high beam ground

Red/Blue: 12v supply

Yellow/blue: low beam ground

 

On these cars the Grounds are switched, Not the supply.

 

Bulb unplugged, testing at the factory socket, voltmeter grounded to battery -

Low beam position you will have 12v only on the supply wire.

High beam position you will have 12v on the supply wire, and (if the car has factory fog lamps), will show 12v on the yellow/blue wire if the fog lamp switch is On. With fog lamp switch Off, you should only have power on the supply wire.

 

What will change is continuity to ground. On high beam position, continuity to ground will be on the Red wire.

On low beam position continuity to ground will be on the yellow/blue wire.

Thanks I appreciate that.

 

But one other question is. In the low beam position. Voltmeter grounded to battery. Why do I have 12v on two of the wires?

Sorry, forgot about the high beam indicator. In low beam position You'll have voltage on the high beam ground wire because of the indicator light.

Whenever you supply power to an open circuit (due to a bad ground or open lamp) you will see full voltage at any point on that circuit if no current is flowing. It is best to test for power with the circuit connected up normally. Otherwise you may get confused about the real problem. From you stated about the problem I have to think the light switch is wired backwards somehow.  

Ok guys I think I have this figured out. I'll update when I verify. But thanks for the help. So what I figure is. Since this is switched ground. And I'm plugged into a premade hid relay harness. It's wired traditionally. Expecting the ground to be where the legacy power wire is. And has a ground where the normal power should be. I think if I just wire this up like a switched ground. It'll be ok.

Yeah if that harness isn't designed for a switch ground system it won't work right.

You'll probably just need to run a separate power wire for the HID ballast.

The high beam can be connected right to the stock wiring, but if you're doing wire work already I would suggest a relay and separate power wire straight from the battery for the high beams as well. Higher constant voltage at the bulb will give you better light output.

The relay can be right at the headlamp and just use the common supply and high beam ground wires in the factory harness to trigger the relay on.

Edited November 7, 20169 yr by Fairtax4me