The seat belt mechanism is making a squealing noise - I want to get into the mechanism how do I get into the mechanism?

Probably should replace the belt. A worn belt will squeal sometimes.'
Another thought is the belt tight enough A belt that is too loose will squeal under stress .

No,the timing chain needs to be replaced.Here's a link on replacing it, SAVE 20 GET 10 GIFT CARD ON ONLINE SHIP TO HOME ORDERS OF 100 OR MORE Did he take apart to see timing belt and components.You can take to another mechanic for a second opinion.

Squealing noises are more apt to be from belts, not mechanical parts. It doesn't necessarily have to be "a belt" per se, as the noise could, in part, be caused by an idler pulley. Open the hood and try to locate the sound. FYI I have posted the complete 2004 Forenza Service manual on FIXYA. Do a site search with those key words.

Year make and model ??
The belt could be glazed and slipping even if it is tight.
You could have a weak belt tensioner too.
The noise when the ac or heat is turned on can be the extra load from the ac compressor or the alternator. The compressor cycles on and off especially in defrost mode.
The load from the alternator is the first noise of the day. As the belt warms up it becomes better at handling the load of the accessories.
Even tho the belt looks fine, you may have to replace it to get rid of the noise.

The squealing noise you describe is usually from a slipping belt. The belt tensioner may be faulty and not keeping the belt tight enough, the alternator is charging and putting a load on the belt when you first start the engine. If the belt squeaked constantly I would say the belt is glazed.

So many mechanics, so little consensus. Sounds pretty common.
I can't say as to why hot and cold only when moving, but it sounds like a weak performing system.
As for the squealing, I would suggest removing one belt at a time, and see if one eliminates the squeal. That would be the problem belt or pulley or component. Also, if you have any idler pulleys (a stand-alone pulley) on the belt system, be sure and check them as well. Spin them without the belt on, and see if they make any noise.
It would seem you need a mechanic who is willing to spend some time with you on this to find the problem. When you find a good one, you will know it by his output, and make yourself a regular customer. Good luck.

This usually means the belt is loose or needs to be replaced. You can take it to a mechanic or your local auto parts place (auto parts places can usually look at it and tell you if it's loose or needs to be replaced). If there is a grinding sound with the squealing, you should take it to a mechanic (this usually means you have a pulley that is freezing up) if the pulley freezes to long, it will break your belt. Good Luck!

When your drive belt becomes old and stretches so it is no longer tight enough the belt will make a loud squealing noise and will need to be replaced. While the drive belt is off during replacement, you or the mechanic replacing the belt will need to turn each pulley in the system that can be turned by hand to see if any of those are making a metallic noise also. If they make a metallic noise, they are worn out. It is common for a drive belt to wear out and cause this noise.

You didn't mention the alternator, power steering pump, or water pump. In fact, any pulley other than the crankshaft one can have a bad bearing or dry seal. Remove the belt and spin each pulley while listening for any rough noise or squeal. If it was the crankshaft, it might be time to check the oil. Start the engine with the belt off to see if it does squeal. Make sure the noise isn't coming from the radiator fan(s).

I would try replacing the belt first because it is a cheaper fix. Are you certain it is the belt? Have a mechanic check your alternator. It could be that actually making the noise. I had a vehicle that made noises and it turned out to be a water pump going bad. I hate car problems!