I think it's just a faulty ballast - help. 2008 GS450h 50K miles and otherwise trouble-free; no local corrosion or similar.

 

Its common for the ballasts to go bad, bummer at such low miles. I would try to clean the terminals on the main plug maybe moisture.

If you do replace the ballast go for oem, or even used oem aslong as you match the part numbers.

 

Yes, thanks.

Reasoning so far:
* Can't be the earthing point, which is shared with the full-beam on the same (off-) side, and which always works. Also, no flickering etc that's caused by bad contact. The HID dipped works 98% of the time and then just stops entirely and then starts again
* Since both ballasts are identical (part #s), I intend to swap them around, which will either confirm or refute it is the ballast.

Why did you say it must be OEM and not aftermarket replacements if they have the same p/no.?

 

I replaced the ballast with a 3rd party one - all's well and that's still the case 3 months later. :-)