sensor electrical connector removal
 

Hello, my engine wiring harness for my 82 300sd is toast. I'm trying to build a new one using good wire, but I'm having trouble getting some of the connectors off. The connectors that push on to the sensors like coolant temperature which are about 1/2" round with only one wire going to them is specifically the ones I'm trying to get at. Has anyone gotten one of these off without ruining it?
Thanks
Corey