Whatever rotates inside is making a lot of noise.

Clogged unit, it's over heating. Run vinegar through it to remove deposits.

There are a number of items you could use to cover (repair) the exposed wire. I agree the quickest repair would be to use electrical tape, everyone has it at home but I don't find it very durable. The easiest, most durable, waterproof, and coolest solution would be to use Bondic
Bondic The World First Liquid Plastic Welder Not Glue

I found it the other week at my Redmond's Home Hardware store and I keep finding things to use it on. It has a precise applicator and the flow of material is very controlled so it allows for very tidy repairs.

You could also use liquid electrical tape, it's messier but it will stick better than regular electrical tape

You aren't giving us a lot of information but if you are referring to the part that makes an increasingly irritating whine as you drive when it starts to go bad, it would be called the axle bearing. That's the only thing that I can think of that would be associated with the axle behind the passenger tire. It sure got my attention in my 1999 Grand Caravan. When they make noise, it means the bearing is going bad / producing a lot more heat than normal. It isn't real hard to change out if you don't let it go too long. It is a complete unit including the bearing, flange and wheel studs. If it goes on too long, it will expand inside the hole that the bearing goes into then it might take a car lift, a torch and sledge hammer to get it out. It happened to me. Good luck. Jeff M.

What is the model number of the unit?

No, the oil does not break down over the years of service. These units are made and sealed from the factory. The purpose is to make a unit that does not require repairs and will run for years. It appears that the TSTAT is not sending proper amperage through. My suggestion is to replace the unit as it costs more to repair then to replace.
Sorry for the bad news, but these units are just not meant for service, hence the price.

Check the baffles in the dryer drum to see if any are loose. If they are not loose, spin the dryer by hand to see if noise is from inside the drum. Sometimes you will get coins caught in the baffles and all you have to do is loosen the screws, and rotate the drum a little so the coins will fall out. Then tighten the screws up and replace the cabinet. You may also have a bad drum roller inside the machine.
If you could describe the sound to me, I will be able to help you a little more.

You have a lot going on inside the transmission. Hard to say what the problem is from here but whatever it is you had best get it into the shop before the banging metal makes the trannie little more than scrap metal for the recycle bin..

Bathtub heaters will not produce the heat out a the jets like you would feel coming out of a return jet in a swimming pool.
Bathtub heaters will ONLY maintain whatever temperature water you put in there. they only heat 1-2 degrees an hour. that is for a 1500 watt heater. Many heaters today are only 650 watt or perhaps 700 watt.

Have you tried the switch yet? The plastic switches inside some ballast boxes don't do well with the heat produced by the ballast. You can try to simply bypass the switch and hard wire the ballast to the plug to test whether or not that might be your issue. If you need a new switch, just call Sunlight Supply directly http://www.sunlightsupply.com/hort/contact.aspx they should be able to send you a replacement switch.

Confirm there is 240 VAC powering the unit (make sure a breaker has not tripped or a fuse blown.).

Did the burners ever produce enough heat?

If yes, then we can look deeper. If no, then the burners may not be adequate for your cooking style. Burners are like light bulbs. A 60 watt bulb will put out more light than a 40 watt bulb. A 100 watt bulb will put out more light than a 60.
Typically, a small burner will provide less cooking heat than a large burner.