Head lights how do I change the head lights on my 2004 trailblazer they are sealed and dont just come out

fuse blown first. any time electrics fail this is first.
head light relay is next.

Hello there

the cylinder head on your truck needs to be machined and if it's really bad then you need to get good cylinder head

U will need to remove the grill which snaps on. remove the clips take unhook the head light.. Follow the wires and un connect it from there replace with new harness and do the reverse

flashing light means dont drive or u can or will cause more damage to vehicle --[the computer is registering a damage causing malfunction] can be reason oil on plugs --need to have code read to properly pinpont problem--as to oil on plugs multi reasons such as bad oil seals on valve--valve bad-bent-burnt---head damage-gasket-cracked-warped---piston-cylinder-rings etc--need to do a compression test to determine the extent of damage

There are 2 methods, 1 involves removing the grill. I'm not a fan of this, because it's brittle.

Drivers side- stick you hand down by the alternator and over behind the headlight. You'll feel a 3" round rubber boot. Pull this off and now you can twist out the bulb and replace.

Passengers side- remove the top of the air cleaner. You'll now have plenty of room to get in there and change this side, same procedure.

check the starter relay and the main cable connected to the starter, also turn the head lights on and try cranking the engine over while watching the head lights, do they go out? if yes the wire on the starter is loose, if the engine does not crank and the lights stay on then it's the starter relay or the main starter wire, if the cable is tight then it may be the safety neutral switch which is on the side of the transmisson, let me know if you need more help.

Most likely the head light switch

you need to remove the grill, a small flat head screw driver will do the trick, you will need to push down on the clips under the hood and pull lightly from the head light assembly and grill just comes off. Then you will need to pull up the two clips on the top corners of the head light assembly. this will free up the assembly this way you can easily remove the bulb and replace it.

chek the bulblamp

Could mean a variety of things.....
Possible head gasket leak....(cheap fix if caught early)
Possible Worn piston rings
possible valve guide oil seals