We have detailed headlight change procedures at our enthusiasts forum
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If it is similar to my Bravada there are 2 clips that hold the entire assembly in place Lift these clips and lift out assembly then remove flexible plastic cover and bulbs are accessible
Remove the wiring harness from the back of your 1999 Chevy Astro headlamp. Remove the headlamp retaining bolts. The headlamp will come out. Reverse the process to install the new headlamp.
the headlamp assembly needs to be removed. remove the 3 "scrivets" in the top of the grill and remove grill. remove 2 x torx headed screws in the top of the headlamp and 1 Philips headed screw that is alongside the headlamp behind a small plastic hinged door. headlamp can now be removed and the relevant cover removed to access the bulb.
you need to remove the front fascia to remove the headlamp to change the bulb
If you want to change just the bulb, remove the small plastic on top of the light from the engine compartment, and turn the light even with the wire harness attached, the bulb will come out.
Well you can take two approches to changing the headlamp bulbs. First, although it is a tight fit you can pop the hood. remove the black plastic guards(for lack of a better word) you will see what im talking about, and reach your hand in the rear of the head lamp, remove the rubber cover and pull the bulb out and change. Another way is to remove the grille, and trim that fits underneath the headlamp, and remove the whole headlight assembly. it is alot easier to see what you are doing with the headlamp assembly removed
2 sliding bars hold headlight in remove and pull headlamp forward and out
Open the hood to the engine compartment. Remove the headlamp wiring harness. Remove the headlamp assembly retaining bolts. The headlamp will come out.
Remove the air intake splash shield from the vehicle. Remove the 2 headlamp retaining bolts. Remove the lamp assembly from the front of the vehicle. Detach the headlamp connector. Remove the headlamp bulb retaining ring. Remove the headlamp bulb from the headlamp.
On the old-style Tigra, (up to 2001) you have to take the front bumper off, and remove the headlamp from the car. (Unless your hands are the size of a 3 year old's, and as flexible as an octopus tentacle)
remove the black plastic radiator cover (push-pins) then remove the two bolts holding the headlamp in unplugh the bulb harness and remove mess around with the screws and clips on the headlight assembly, but i dont know if you can take the front clear plastic piece off. (and be able to put it right back on..)
Remove the (2) two headlamp assembly bolts from the upper fascia support. Slide the headlamp assembly outward enough to release the headlamp bracket tabs from the slots in the upper fascia support. Position the headlamp assembly away from the vehicle body to access the electrical connector. Disconnect the electrical connector from the headlamp assembly. Remove the headlamp assembly from the vehicle. If you wish to change the halogen bulb: Disconnect the electrical connector from the headlamp bulb/socket. Remove the headlamp bulb/socket retainer ring from the headlamp, by turning counterclockwise. Remove the headlamp bulb/socket from the headlamp assembly. Hope this helps. G These instructions are similar from around '96 to '03 grand prix model years.