My sun roof on my 2002 don't wrok - 2002 Chevrolet Monte Carlo

need service get it?
the channel tracks are bad or broken or dirty.
clean out?
that is never strange, broken or thermally.
I hate sun roofs most are made with cheesy weak cheap plastic parts. that LOVE TO FAIL. my Jeep is a convertible; vastly better
google sun roof fails, and cry. (vast did)
and always fails (stuck open) when it rains, (murphy;s law)

sure in physics 101 google how materials expand hot.
icing too.fails (packed in ice)
even the car body can expand hot,and does.
google material thermodynamic expansion and contraction.

https://en.wikipedia.org/wiki/Thermal_expansion

the drain hole for the sun roof may have come off. or the roof panel is leaking some were check the rim on the roof. sun roof has 4 lines two at the front and two at the back, the two at the back you cannot see as it goes into the roof lining if you park on an incline with the engine up then the rear ones are iver blocked or the lines have come out.

Try manually moving the deflector that pops up as the roof is opened. Something may be jamming it and preventing it from retracting.

CHECK SUN ROOF FUSE.IF GOOD CHECK FOR POWER AT SUN ROOF SWITCH.IF YES SUN ROOF MOTORS WIRES COULD BE LOOSE OR BROKEN OR SUNROOF MOTOR FAULTY.

CHECK YOUR FUSE. IF YOUR FUSE IS GOOD, THEN CHECK THE SWITCH, IF YOUR SWITCH IS GOOD THEN REPLACE YOUR MOTOR.

Most likely cause is the gasket around the Sun Roof. Most auto parts stores have a gasket kit to do it yourself. It is time consuming but much cheaper than having a dealer or sun roof specialist replacing it.

If you have a sun roof,the drain hose may be off. If so,remove the sun visor and pull down the head liner, to get to the hose and drain fitting on the sun roof opening

have the rubber seal around your windshield check by a wind shild installer base on what you explain the sel at that corner is leaking and the water is leaking back into the vehicle

It's typically the motors or the special drive tubes that it uses. If you here a clicking noise then the sunroof became to tight and ruined the motor gears. You can actually switch the two motors, one is for the shades and needs less power then the other motor. They are identical, switch them. Nex make sure they are very tight to the 3 mounting bolts, there is a rubber washer bushing that wears out and alloys the motor to flex too much, causing the gear mis-alignment and gear grinding. This works great I do it all the time.

Yes, but you need to remove the motor to do so.