I have an old leisure bay tub that has a blown contact switch. I have removed the cover of the switch and I can press on the spring loaded center contact to get the heater to turn on, but it doesnt work on its own. Part number on the switch 3100-20T3347C. Anyone know where I can find one or what an equivalent replacement would be?

The switch is a contactor. Either a single pole single throw, or a double pole double throw.
The ratings are usually 50 amps. The coil of your contactor will be 110 volts.
The question is, is there voltage on the coil terminals?
If you push down on the carriage when there is no voltage to energize the carriage,
the results will be the same.
The Heater Contactor is run by the Thermostat, high limit, and pressure switch.
If they don't "Call" for heat, then no carriage action.
Check all before popping for a new contactor.

Already bought a new contactor. No biggy, the tub was free so im not into it for much if I buy parts i dont need. Still doesnt work. I have power going to the L1 and L2 side of the contactor. Nothing on the T1 or T2 side (the T side is wired closest to the heater). Light for heater is on if that means anything.

Are you asking about the coil terminals on the contactor? If so, I dont think I have power to them. I will have to check again but Im pretty sure there was no power on the new contactor when wired.

Where do I find the high limit and pressure switch?

Ok, got power going to the contactor now. Coil has 110v going to it as well. I guess the tube going to the switch got pinched when the tub overflowed with rain water. Still no power going across the contactor.

Power at the coil (110 volts) needs a path. If you are reading across both coil terminals and getting 110 volts, then you should get the carriage to drop. If you picked up a 220 volt coil contactor, then it wouldn't energize. (just buzz) If you get zero accross the coil terminals, then you are missing line, or neutral.
So ...
forget T1, and L1 (loads) we've established that they are there.
Always read coil voltage from one side of the coil to the other. Never one side to ground.
110 volts across coil makes the world go round.
No voltage = no pressure switch completion. (funny looking round thing screwed into the 3"
verticle heater canister, or in the 2" flow through heater chamber.Older packs mounted the pressure switch to the back of the controller, and fed it with a brass hose barb, and lexan tubing.)
You also may have a capacitor across the coil set. It will be a green "chicklet" looking piece.
It's job is to soften the current to the coil, and reduce "chattering" that spikes other components.
If it were thrown out, no big deal.
Usually, Hurricane Products used orange to feed line from pressure switch, and of course, white for commons, and neutrals.

OK, well, no power across coil. I was going from terminal to ground. Sounds like I need to track down the pressure switch. Would it be the next component in line tracing back from the wire that leads to the contactor coil? Also, would it be adjustable from 1-5 psi? I have looked at that piece a little when I found the tube leading to it was pinched.

Also, shouldnt the coil have a neutral wire attached somewhere? The first contactor in the circuit has a neutral and I have continuety from there all the way to neutral coming in. I dont know if I missed a wire when hooking up the contactor that I thought was blown , but there is no N attached as of now.

Yes on the neutral. AC needs a neutral to complete the circuit. The neutrals are bundled, and daisy chained throughout the pack. Look again for a group of wires possibly hidden behind a component.

That was it, back in buisness, Thanks.