1991 1999 ford explorer chilton User Manual

							Remove the starter motor (arrow) mounting bolts ...
Remove the starter mounting bolts and remove the starter.
4. 
... then remove the starter-be careful, the starter motor can be quite heavy
To install:
Position the starter motor against the engine and install the mounting bolts. Tighten the mounting
bolts to 15-19 ft. lbs. (21-27 Nm).
5. 
Install the starter solenoid connector by pushing it straight on. Ensure that the connector locks in
position with a notable click.
6. 
Install the starter cable nut to the starter solenoid B-terminal. Tighten the nut to 80-123 inch lbs. (9-14 Nm). Connect any remaining wiring to the starter motor.
7. 
Lower the front of the vehicle and remove the wheel blocks.
8. 
Connect the negative battery cable.
9. 
RELAY REPLACEMENT Disconnect the negative battery cable from the battery.
1. 
If necessary, remove the power distribution box cover.
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232 RELAY REPLACEMENT 
						

							Label all of the wires on the starter relay before removing them
Also remove any protective caps
Remove the push-on connectors by pulling them straight off
Disconnect the positive battery cable from the battery terminal.
3. 
Remove the nut securing the positive battery cable to the relay.
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RELAY REPLACEMENT 233 
						

							Remove the cable securing nuts ...
Remove the positive cable and any other wiring under that cable.
5. 
... then remove all of the cables from the relay
Label and remove the push-on wires from the front of the relay.
6. 
Remove the nut and disconnect the cable from the starter side of the relay.
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234 RELAY REPLACEMENT 
						

							Remove the relay-to-fender apron attaching screws ...
... then remove the relay from the fender
Remove the relay mounting bolts and remove the relay.
8. 
To install: Install the relay and mounting bolts. Tighten the mounting bolts until snug.
9. 
Attach all wiring to the relay.
10. 
If equipped, install the power distribution box cover.
11. 
Connect the positive (+) cable to the battery.
12. 
Connect the negative (-) cable to the battery.
13. 
Chilton® Automotive Information Systems. © 2004 Thomson Delmar Learning. HOW TO USE THIS BOOK
RELAY REPLACEMENT 235 
						

							
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 
						

							Temperature gauge diagnostic chart
Click to enlarge
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238 TESTING 
						

							Temperature gauge and sending unit wiring schematic
Click to enlarge
Remove the coolant temperature sender from the engine block.
1. 
Attach an ohmmeter to the sender unit as follows: Attach one lead to the metal body of the sender unit (near the sender units threads).
1. 
Attach the other lead to the sender units wiring harness connector terminal.
2. 
2. 
With the leads still attached, place the sender unit in a pot of cold water so that neither of the leads is
immersed in the water. The portion of the sender unit which normally makes contact with the engine
coolant should be submerged.
3. 
Measure and note the resistance.
4. 
Slowly heat the pot up (on the stove) to 190-210° F (88-99° C) and observe the resistance of the
sender unit. The resistance should evenly and steadily decrease as the water temperature increases.
The resistance should not jump drastically or decrease erratically.
5. 
If the sender unit did not function as described, replace the sender unit with a new one.
6. 
REMOVAL & INSTALLATION CAUTION
Ensure that the engine is cold prior to opening the cooling system or removing the sender from the engine.
The cooling system on a hot engine is under high pressures, and released hot coolant or steam can cause
severe burns.
Disconnect the negative battery cable.
1. 
Remove the radiator cap to relieve any system pressure.
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REMOVAL & INSTALLATION 239 
						

							The sending unit uses a push-on wire connector. To remove, simply pull straight up from the
sender
Disconnect the wiring at the sender.
3. 
Remove the coolant temperature sender from the engine.
4. 
To install: Coat the threads on the sender with Teflon® tape or electrically conductive sealer, then install the
sender. Tighten the sender to 107-143 inch lbs. (12-16 Nm).
5. 
Attach the wiring to the sender and connect the negative battery cable.
6. 
If necessary, add antifreeze to replace any lost coolant, then install the radiator cap.
7. 
Water temperature and oil pressure sending units on the 2.3L, 2.5L engine Click to enlarge
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240 REMOVAL & INSTALLATION 
						

							
Oil Pressure Sender and Switch
Oil pressure senders are used for oil pressure gauges, whereas the oil pressure switches are used for
vehicles equipped only with a low oil pressure warning lamp.
The oil pressure senders/switches are located as follows: 2.3L, 2.5L engine-Left side rear of the engine, in the cylinder head
· 
3.0L engine-Behind the right cylinder head, in the engine block
· 
2.9L and 4.0L engines-Left side front of the engine, below the cylinder head in the engine block
· 
5.0L engines-Left-hand front of the engine, below the rocker arm cover
· 
TESTING
Oil pressure sender and gauge wiring schematicClick to enlarge
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Oil Pressure Sender and Switch 241 
						

							Oil pressure gauge diagnostic chart
Click to enlarge
Oil Pressure Sender
Use the accompanying diagnostic chart to help pinpoint oil pressure sender and oil pressure gauge
malfunctioning.
Oil Pressure Switch To test the oil pressure switch, open the hood and locate the switch.
1. 
Disconnect the wire from the switch. Attach one end of a jumper wire to the terminal on the end of
the wire, then touch the other end of the jumper wire to a good engine ground (any bare metal engine
surface). Have an assistant observe the instrument gauge cluster while you do this and tell you if the
low oil warning lamp illuminates or not; the low oil warning lamp should illuminate. If the lamp does not illuminate, skip to Step 3.
1. 
If the lamp does illuminate, replace the switch with a new one.
2. 
2. 
Before jumping to any bad conclusions, try a different area for grounding the jumper wire on the
engine. If the lamp still does not illuminate, touch the jumper wire end to the negative (-) battery
post.
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242 TESTING