Has the battery been disconnected, or has it gone dead? Every time the battery is disconnected, all trouble codes are cleared, the check engine light is turned off, and all system monitors are reset. For the monitors to get back to a 'ready' status, the vehicle needs to go through one or more (sometimes quite a few) drive cycles.
When you go to the emission station, they check for codes, AND also check to see how many of your monitors are in a 'ready' status. (This keeps people from disconnecting the battery, and thus clearing any trouble codes, in order to pass emission tests).
If you have not disconnected your battery for a while, but the monitors are still not showing 'ready', you need to have a qualified shop check out your computer and other electronic systems.
Although some keys do not have an embedded transponder, such keys are designed to give access to the vehicle only and not to allow engine starting.
To allow engine starting there must be an embedded transponder in the key, programmed with the correct code.
In the early days of passive immobiliser systems some manufacturers used a key fob to operate the central locking and to house the rice-grain-like transponder chip. Sometimes the key or the fob would break and the owner would attempt to start the engine fruitlessly as the fob would be in a pocket or handbag (purse). The fob had to be within a few inches of the ignition/steering lock...
First while the engine is running, look under the hood and see if the air conditioner compressor is turning. If it is not then using gauges hook them up and see if the system has pressure. If both gauges show 80 psi or more then you have an electrical problem somewhere in the system. Check fuses and connections. Hook up a 12volt feed wire to the positive feed connector on the compressor( green wire). If it starts running then check the electrical system.
If there is no pressure or very little then there is not enough pressure to override the low pressure switch. Carefully add a lb of 134a freon to the system and see what happens.
Usually if there is a howl on acceleration from the rear it's the big pinion bearing,if the howl is on deceleration it's the small pinion bearing.(the pinion shaft with these bearing is the one in the diff that the driveshaft attaches to)
I'm assuming it's an automatic. That being said I'm also guessing it's a V6 with a distributor back by the firewall.
THAT could be the 'clicking' you hear. IF my assumptions are correct i would remove the distributor cap and look at the terminals on the underside. You may very well see the terminals have had contact made to them by the rotor. Thus causing the 'clicking' and stalling. The distributor could be worn and has an excessive amount of 'slop' or play in the area where the shaft goes thru the housing. Causing the rotor to wander and hitting the terminals.
Most likely a shift solenoid problem. It could turn into a valve body failure if filter changes have been neglected. Another possibility is a failed transmission control module. All of which can be repaired
The white smoke is probably steam caused by coolant getting into the cylinder(s) either from a faulty head gasket, cracked cylinder head or cracked engine block. The loss of heat from the heater indicated that coolant was being lost..
Make sure there is enough coolant in the engine ... if you are a few quarts low it will not get to the heater core. If there is enough there is something wrong with your heater door / actuator or cable.
Probably clips are broken...Check with auto body store that has clips . It might be as simple as replacing the clip and snapping the panel back into the mounting hole. It may be a bit tricky so take time to look at how it is mounted. Usually once you pull the whole panel off the other clips will break so you will need a few replacements. Most are plastic and relatively cheap. Super glue will not work.. When it gets cold the glue gets brittle and cracks. That is why panels are held on with clips.
There is a possibility that both bulbs are burned out or the paste that GM seals the lamps sockets with is preventing a good connection between the contacts.
Remove the bulbs and test for power (with the brake pedal depressed or the running lights turned on.)
If your multi meter reads voltage, it's the lamps, if not...check for continuity on the brake light switch (connected wires removed.)
The headlight switch controls the running lights, the brake light switch controls the brake lights. Good grounds are also critical so make sure they have clean solid connections.