Ford Explorer, Maintaince And Repair Manual, Page: 245 / 1119

SENDING UNITS
Introduction
This section describes the operating principles of sending units, warning lights and gauges. Sensors
which provide information to the Electronic Control Module (ECM) are covered in Section 4 of this
manual.
Instrument panels contain a number of indicating devices (gauges and warning lights). These devices are
composed of two separate components. One is the sending unit, mounted on the engine or other remote part of
the vehicle, and the other is the actual gauge or light in the instrument panel.
Several types of sending units exist, however most can be characterized as being either a pressure type or a
resistance type. Pressure type sending units convert liquid pressure into an electrical signal which is sent to the
gauge. Resistance type sending units are most often used to measure temperature and use variable resistance
to control the current flow back to the indicating device. Both types of sending units are connected in series by
a wire to the battery (through the ignition switch). When the ignition is turned ON, current flows from the
battery through the indicating device and on to the sending unit.
Coolant Temperature Sender
The coolant temperature sender is located in the following positions:
2.3L, 2.5L engine−left side rear of the engine, below the cylinder head •
3.0L engine−top front of the engine, on the intake manifold •
2.9L and 4.0L engine−top left front of the engine, on the intake manifold
•
4.0L SOHC engine−top front of the engine, on the intake manifold •
5.0L engine−top front of the engine, on the left−hand side of the camshaft synchronizer •
TESTING
Before going to the trouble of removing the sender from the engine block and testing it, perform the tests
presented in the accompanying chart to ensure that it is the sender malfunctioning, and not another part of the
circuit.
SENDING UNITS 237