For some reason my car doesn't lock when I hit the lock button on my remote entry key. Also, when I'm inside the car, if I try to lock it using the lock switch on my door, it doesn't work. The only way I can lock it is by physically closing the lock mechanism on the drivers side. It doesn't end there either, lately my remote entry has stopped working sometimes, I have to press the unlock or lock buttons like 10 times for it to actually turn on my alarm (keep in mind, it doesn't actually lock the doors, just arms the alarm). And even further, as I was driving tonight, my tach started to bounce like crazy, it went all grand turismo on me and looked like I was revving with a 1 pound flywheel. What the hell could these be caused by? Bad electronics? bad connections? I have no idea. thanks for your help.

Cliff Notes :
- Alarm doesnt lock
- Doesnt unlock inside the car
- Tach doesnt work

 

Could be anything, start with changing battery in remote and see what happens.
Check the relay box for your power locks(im guessing you have stock power locks)
tach going crazy, check the wire harness for that if its lose or whatever.