The coolant level sensor seem to be going bad on my 1999 Monte Carlo. Initially, it was just flickering and going on/off, but lately it's often 'on' all the time. I just checked and the coolant level is up to the top, so the issue can't be lack of coolant. After some struggle I was able to disconnect the connector with a long screwdriver for testing, but I was unable to reconnect it - there is simply not enough space for my fingers and hand.

How can I replace the sensor and reconnect its wiring? What needs to be removed or moved to get adequate access for replacement?

BTW, I got my service manual last week, but it's not particularly helpful.

 

The first time that thing started blinking I was in panic mode and stopped the car right away and checked it out. But all was good.
Now if it was a Ford which I had once and it said that on a sensor you would be screwed the minute it appeared. Happened to me on a trip and it warped the heads and blew the head gaskets, had to leave it and get a rental to get home.
Most of us just leave it unplugged and we check the coolant level when we open the hood. Coolant level should only be up to the lines on the reservoir tank, not up to the top.