Weird HID issue - strobe lights!

[KenC]

Yeah, it's a 91 318is.

How would I temporarily ground the ballast? Hook the black wire to a ground?

If the third wire is hooked directly to the highbeams, that may explain why they glow very dimly while the HIDs strobe.

Which wires on the factory plug should the ballast hook into? Right now it seems to be the two positive leads (if I'm correct that the factory brown lead is ground).

[DaveSmed]

I'm gonna go out on a limb and guess this was a factory sealed beam car?

That 3rd wire is connected directly to the highbeams, which explains the funky grounding.

What it doesn't explain, is why are the highbeams grounded OK through the same brown wire that ends up getting spliced to the lowbeams brown wire.

If the continuity to ground does not check out, inspect where the wire is crimped to the terminal in the plug for damage. Also, if temporarily grounding the ballasts works, there should be no harm in making a permanent separate ground if you wish.

[KenC]

When I have the leads from the ballast into the factory headlight socket, neither of them are plugged into the brown factory lead (it won't turn on if either of them is).

[DaveSmed]

I did a preliminary install of some HIDs last night.

Install passenger side: everything works perfectly.

Install drivers side and turn lights on: I get an alternating strobe effect from each low (HID), and the highbeams (H1) glow very dimly. The high beam switch is not flipped on at this point.

If I have just one hooked up on either side, it works fine. But as soon as I have both ballasts hooked up, I get the alternating strobe from each.

Sounds like the HID is trying to find a ground through the H1s. Both H1s combined make an "okay" ground for one ballast, but not both.

Make up a temporary separate ground for the ballast to check, and verify the brown wires at least have basic continuity to ground.

[KenC]

I did a preliminary install of some HIDs last night.

Install passenger side: everything works perfectly.

Install drivers side and turn lights on: I get an alternating strobe effect from each low (HID), and the highbeams (H1) glow very dimly. The high beam switch is not flipped on at this point.

If I have just one hooked up on either side, it works fine. But as soon as I have both ballasts hooked up, I get the alternating strobe from each.