Kenwood TM 733 turns itself on/ off

Of course I’ve checked the 12v power cord/ fuses, grounds. It’s installed installed in my car to always on direct to battery +12v & neg. Rig is under seat and head is up in the always open headliner sunglasses storage area. When it shuts itself off… I have 12v voltage and ground to radio. Can’t re-start it via display on/off switch (… no matter how many times I push it!). Days later I can hear voices coming from the car as I approach it/ radio has turned itself back on and still on local repeater. Could be the separation cable, but before I go though all the work to pull headliner out check every inch of run for chaffing and both end multi-contacts, thought I’d ask if anyone else has had similar issues. I have checked radio end of selection cable already… head is spot glued into its position by few dabs of silicone sealant and therefore a bit more involved.