Joe P nailed it. I'd bet it's in your ignition switch. Everything you describe could be explained on the basis of the switch not turning off. That's why the antenna doesn't retract. It's why your doors don't lock since the car "thinks" the key is still in the ignition and it's designed so you DON'T accidentally lock your keys in the ignition...

Wiring harness problems usually engine-related problems, I believe.

Incidentally, the 400E doesn't have an OVP. The functions of the OVP are incorporated into a fairly expensive "module" in a box under the hood.

__________________
Steve
'93 400E