The instructions below apply to the 3rd gen HALOGEN headlights. Instructions for the HID/LED units with the motors in the housing on the GTs may be different.
(If someone wants to make edits/additions to this for the GT, please PM me, and I'll add them in)
From the factory, the headlights are generally aimed very low. So, before exploring a bulb upgrade, it's a good idea to get your lights aimed correctly first.
The headlight adjusters are on the back of the headlight housing. The top edge of the bolt head has a toothed ridge, and the center is a hex head - this allows you to adjust the aim with either:
- a long (8" or longer) #2 phillips screwdriver OR
- your 8mm socket/wrench/nutdriver of choice
Philips method is a LOT easier to do, IMO. but, if you choose to go the 8mm route, the clearances are tight. ratcheting wrench is probably your best bet. (If you don't have a long screwdriver, it's a $5 investment at your local hardware store)
There's only one vertical adjuster for the headlight assembly. it moves BOTH the low beam and the high beam. Be sure to test the high beams when you do a test drive post-adjustment - if your aim is too high, they will become useless.
Remember - small steps are better than big ones (especially when raising the lights), and if people are flashing you while you're out of the roads, odds are your lights are aimed too high.
Full factory instructions for adjusting the aim (the "how high") can be found here: HEADLIGHT AIMING
Helpful extras - screwdriver method:
- The pics attached to this post will help you locate the right holes in the body for the screwdriver.
- clockwise raises the aim. counter-clockwise lowers.
Helpful extras - 8mm nut method:
(h/t to @jsouth
- The relay/fuse box on the drivers side can be unbolted (a 10mm nut and 10mm bolt) and moved slightly to allow access with a nutdriver and 8mm socket to the driver's side adjuster.
- On the passenger side, I used a 1/4" drive ratchet and short extension with the 8mm socket and reached it easily.