haas vf2 proximity sensors problem

Hello, I have a 2006 haas vf2. It seems my proximity sensors in the upper part of machine are acting strange.
A few months ago my tool changer stopped working, it just kept cycling the arm over and over without a tool in it because the proximity sensors were not functioning.
I unplugged a cable labeled solenoid on the IO board and reseated it and the tool changer began working properly.
Today I had a z limit switch problem, that went away on its own. After my morning warm up the spindle gear would not go into high gear, it just sit and searches until i get a spindle high gear fault.
I played with the air shutoff and putting oil in line. I found out that it would go into low gear but not high.. I then notice that It would not do a tool change, tool clamp fault. I pulled the cover off and notice
the proximity switch on the left high side of draw bar that the light was not coming on at all when i operated the tool release. So that switch was now not working properly. I turned off power, went
back to cabinet and unplugged and reseated all connectors off of IO board and now everythings working as it should?? tool changer, and high gear. My question is, is there a cable that feeds all proximity switches
in the upper part of the machine that could be bad, or does this sound like the IO board is bad? Thank you

Sounds like the 24V common (return) was a bit cruddy at the connector. Not an uncommon problem for many machines. Normally unplugging and reseating is the correct action.