I need help finding the Temperature Sensor on my 87 XJ. the Engine is a 6cyl 4.0L.

I recently repaired my jeep and got it running again, however the temp gauge isn't getting a reading. Before i tare anything apart i wanted to know what i'm actually looking for. At ignition the gauge needle jumps as the engine cranks, but after it turns over and begins to idle the needle quickly falls back down and doesn't move from there.

I've driven it back and forth to work and kept an eye on the coolant level just to be safe but i would really like to get the gauge working properly. I've looked for anything that would resemble a temp sensor in the front water jacket but i haven't found anything. there is a sensor to the back on the block mounted on top but i believe that is the sensor for the computer.

If anyone has any information pls help me out thanks

 

edit:

On your engine, the CTS is below the exhaust manifold screwed into the engine block. Remove the air box to find it,