Unknown sensor??

Does anyone know what sensor is right above the knock sensor on a 90rs 305 has a single wire connector(broke now) wire is grn/wht

If it is in the cylinder head..that would be the thermal switch for one of the cooling fans.

Nope its in the block between last two plugs on pass. side. car has one fan works fine

That should be the coolant temp sensor for your gauge. I bet your temp gauge doesn't work