Non functioning cruise control and locking/unlocking the doors with the shifter

'02 Protege5
So after taking my new (used) protege from 82 to 84 thousand miles and fixing all the major issues with it (alternator, battery, tires, pads and rotors, etc.) the small issues that I originally didn't care about have started to bug me and are itching to get fixed.

First, the cruise control has never worked. When I press the main button, I hear a relay click somewhere by the glovebox, but no light comes on in the dash and obviously the druise does not proceed to be controlled. I checked what I thought were all the relevant fuses, found no issues, and am now at a dead end. Any ideas? What fixes have people found for this issue?

Another "issue" is more of a feature I wish the car had - modern cars will lock the doors when shifted out of park, and unlock the doors when shifted into park. Now this literally does not matter at all since there's a button for this right on the door, but I always found this less convenient than the system in modern cars. Has anybody wired up the switches (or added switches) into the automatic shift lever mechanism to lock and unlock the doors? Survey on if anybody thinks this is a dumb or cool project?

And lastly, now that I think about it, the switch to switch from reciruculating to fresh air mode has stopped switching - it's stuck on fresh air mode. This is also basically not an issue since I never use recirculation, but I hate having broken things, so I guess I'll just ask if anybody has come across this problem before and what they've done to fix it.
Mazda P5
Pop the hood, there's a vacuum hose from top of the intake manifold to the passenger side is intact. Make sure nothing is loose or broken on that module.
I have a manual and the only feature that locks and unlocks the door is the key it the switch on the door. Never heard of someone installing that feature. I know what you referring too, my wife's crv has that feature. Up to you and hopefully someone can chime in.
The feature of switching air flow from outside to inside there might be something broken from switching it. You can always check by taking it off very easy to do about 15 minutes to do so. If you need a new one let me know I have an extra if yours is broken
When I got my P5 the cruise control didn't work. I think it clicked (can't remember, that was a long time ago) but nothing happened, no light, etc. I found the cruise control module was completely unplugged. I plugged it back in and it worked great after that, never had a problem. Someone must have replaced belts or something, moved the cruise servo out of the way and forgot to plug it back in. It's in the very back corner on the passenger side of the engine compartment.

As for the door locks, Mazda likes to use multiplex. So I don't know if there is an easy way to separate P from the other PRNDL circuits at the shifter. A much easier solution would be to simply add an aftermarket alarm or keyless entry. Most of those come equipped with ignition controlled door locks. When you turn the key on to start the car, they lock. Turn the key off, they unlock. If you have an automatic, and live in IL you'd probably benefit from the additional features if you add an alarm with remote start :) Again, the door locks are multiplex so you'll need some knowledge of relays and how to interface with that. Basically 1 wire controls both lock and unlock. A straight ground pulse to that wire will do one, and a ground pulse to the same wire through a xxx resistor will do the other, I don't remember specifics off the top of my head but you can find all the information for free to wire it at under the vehicle wiring tab.

As for the recirc, it's probably either the door is jammed (frequently find stuff falling out of the glove box and getting stuck, or leaves/twigs from the outside getting stuck) or the servo motor is just dead. Either way it's a cheap (possibly free) fix. I don't know that I've ever heard of the AC control head going bad with just the recirc function, but anything is possible i guess.
That's the exact same thing that happened to me, love easy fixes :) funny how things work when they're plugged in...

must be common for someone to unplug it to replace belts or something... i'm really not sure. I replaced the timing belt on mine twice, motor mounts, etc. I never had to unplug it for access to anything