I need to know how to add a ground wire to the ECT if for the sensor.The gauge doesn't work plug has missing ground wire.any help is appreciated.

 

Welcome to the forum

It is an ECT sender for the temp gauge
ECT sensor is for the computer and has no ground wire.

Sender will have a Red/white stripe wire that comes from the Dash, and a Black/white stripe wire that is the Ground
The sender itself has no Polarity, no + and - connection, as long as red wire is on one connection and the other is a Ground it will work fine.

If the Black wire has been ripped out of the connector then you will need to hit wrecking yard to get a new connector, with a few inches of wire still in place
Then splice them to Red and Black for the Ground

The Ground can be any near by bolt on the engine

 

Is there any way to add a ground wire to an existing plug?

 

??

You can re-pin any connector

Google: ford connector pin removal

There are different types of connectors of course, but there are many videos, lol.

Basically you need to look at your connector and see how to get the ground "pin" out and then how to attach a new wire to it, or the current broken ground wire
Usually you would have to solder it on unless you can get the old pin apart or can get a new pin to clamp on new wire
Then re-insert it into the connector

 

Thank you for the information. I will give it my best I need it fixed. I am all about DIY kinda woman. My daddy taught me that, have a great day. Beachbabie