Temp Gauge Sending Unit Issues (Page 3/3) Rhodesia1977 MAR 26, 02:39 PM My 86 did the same thing. The plastic thing that holds the snap on to connect to sensor was missing. It was just 2 separate green wires both unmarked, naturally! I installed new sensor and then mistakingly switched the wires that go to the sensor and ever since then, it has worked fine. It is off by 15 degrees however. Also, get yourself a Lazer thermometer and take readings at the base of coolant gauge temp sender sensor. It should give you a good idea of the temp.