1991 1999 ford explorer chilton User Manual

							Checking the resistance of a coolant temperature sensor with an ohmmeter. Reading is 1.04
kilohms
Spark plug wires can be checked for excessive resistance using an ohmmeter WARNING
HOW TO USE THIS BOOK
662 RESISTANCE 
						

							
Never use an ohmmeter with power applied to the circuit. The ohmmeter is designed to operate on its own
power supply. The normal 12 volt electrical system voltage could damage the meter!
Isolate the circuit from the vehicles power source.
1. 
Ensure that the ignition key is OFFwhen disconnecting any components or the battery.
2. 
Where necessary, also isolate at least one side of the circuit to be checked, in order to avoid reading
parallel resistances. Parallel circuit resistances will always give a lower reading than the actual
resistance of either of the branches.
3. 
Connect the meter leads to both sides of the circuit (wire or component) and read the actual measured
ohms on the meter scale. Make sure the selector switch is set to the proper ohm scale for the circuit
being tested, to avoid misreading the ohmmeter test value.
4. 
Wire and Connector Repair
Almost anyone can replace damaged wires, as long as the proper tools and parts are available. Wire and
terminals are available to fit almost any need. Even the specialized weatherproof, molded and hard shell
connectors are now available from aftermarket suppliers.
Be sure the ends of all the wires are fitted with the proper terminal hardware and connectors. Wrapping a wire
around a stud is never a permanent solution and will only cause trouble later. Replace wires one at a time to
avoid confusion. Always route wires exactly the same as the factory.
If connector repair is necessary, only attempt it if you have the proper tools. Weatherproof and hard
shell connectors require special tools to release the pins inside the connector. Attempting to repair these
connectors with conventional hand tools will damage them.
Chilton® Automotive Information Systems. © 2004 Thomson Delmar Learning. HOW TO USE THIS BOOK
Wire and Connector Repair 663 
						

							
BATTERY CABLES
When working on any electrical component on the vehicle, it is always a good idea to disconnect the negative
(-) battery cable. This will prevent potential damage to many sensitive electrical components such as the
Powertrain Control Module (PCM), radio, alternator, etc.
Any time you disengage the battery cables, it is recommended that you disconnect the negative (-)
battery cable first. This will prevent your accidentally grounding the positive (+) terminal to the body of
the vehicle when disconnecting it, thereby preventing damage to the above mentioned components.
Before you disconnect the cable(s), first turn the ignition to the OFFposition. This will prevent a draw on the
battery which could cause arcing (electricity trying to ground itself to the body of a vehicle, just like a spark
plug jumping the gap) and, of course, damaging some components such as the alternator diodes.
When the battery cable(s) are reconnected (negative cable last), be sure to check that your lights, windshield
wipers and other electrically operated safety components are all working correctly. If your vehicle contains an
Electronically Tuned Radio (ETR), dont forget to also reset your radio stations. Ditto for the clock.
Also, Ford reports that anytime the battery cables have been disconnected and then reconnected, some
abnormal drive symptoms could occur. The is due to the PCM losing the memory voltage and its learned
adaptive strategy. The vehicle will need to be driven for 10 miles (16Km) or more until the PCM relearns its
adaptive strategy, and acclimates the engine and transmission functions to your driving style.
Chilton® Automotive Information Systems. © 2004 Thomson Delmar Learning.
BATTERY CABLES 665 
						

							
AIR BAG (SUPPLEMENTAL RESTRAINT) SYSTEM
The 1995-99 Ranger, Explorer and Mountaineer vehicles are available with an air bag Supplemental Restraint
System (SRS). The SRS is designed to work in conjunction with the standard three-point safety belts to
reduce injury in a head-on collision.
WARNING
The SRS can actually cause physical injury or death if the safety belts are not used, or if the manufacturers
warnings are not followed. The manufacturers warnings can be found in your owners manual, or, in some
cases, on your sun visors.
The SRS is comprised of the following components:
Drivers side air bag module
· 
Passengers side air bag module
· 
Right-hand and left-hand primary crash front air bag sensors
· 
Air bag diagnostic monitor computer
· 
Electrical wiring
· 
Exploded view of the SRS air bag module and related components
The SRS primary crash front air bag sensors are hard-wired to the air bag modules and determine when the
air bags are deployed. During a frontal collision, the sensors quickly inflate the two air bags to reduce injury
by cushioning the driver and front passenger from striking the dashboard, windshield, steering wheel and any
other hard surfaces. The air bag inflates so quickly (in a fraction of a second) that in most cases it is fully
inflated before you actually start to move during an automotive collision.
Since the SRS is a complicated and essentially important system, its components are constantly being tested
by a diagnostic monitor computer, which illuminates the air bag indicator light on the instrument cluster for
approximately 6 seconds when the ignition switch is turned to the RUNposition when the SRS is functioning
properly. After being illuminated for the 6 seconds, the indicator light should then turn off.
If the air bag light does not illuminate at all, stays on continuously, or flashes at any time, a problem has been
detected by the diagnostic monitor computer.
WARNING
If at any time the air bag light indicates that the computer has noted a problem, have your vehicles SRS
serviced immediately by a qualified automotive technician. A faulty SRS can cause severe physical injury or
AIR BAG (SUPPLEMENTAL RESTRAINT) SYSTEM 667 
						

							
death.
SERVICE PRECAUTIONS
Whenever working around, or on, the air bag supplemental restraint system, ALWAYS adhere to the
following warnings and cautions.
Always wear safety glasses when servicing an air bag vehicle and when handling an air bag module.
· 
Carry a live air bag module with the bag and trim cover facing away from your body, so that an
accidental deployment of the air bag will have a small chance of personal injury.
· 
Place an air bag module on a table or other flat surface with the bag and trim cover pointing up.
· 
Wear gloves, a dust mask and safety glasses whenever handling a deployed air bag module. The air
bag surface may contain traces of sodium hydroxide, a by-product of the gas that inflates the air bag
and which can cause skin irritation.
· 
Ensure to wash your hands with mild soap and water after handling a deployed air bag.
· 
All air bag modules with discolored or damaged cover trim must be replaced, not repainted.
· 
All component replacement and wiring service must be made with the negative and positive battery
cables disconnected from the battery for a minimum of one minute prior to attempting service or
replacement.
· 
NEVER probe the air bag electrical terminals. Doing so could result in air bag deployment, which can
cause serious physical injury.
· 
If the vehicle is involved in a fender-bender which results in a damaged front bumper or grille, have
the air bag sensors inspected by a qualified automotive technician to ensure that they were not
damaged.
· 
If at any time, the air bag light indicates that the computer has noted a problem, have your vehicles
SRS serviced immediately by a qualified automotive technician. A faulty SRS can cause severe
physical injury or death.
· 
DISARMING THE SYSTEM Disconnect the negative battery cable from the battery.
1. 
Disconnect the positive battery cable from the battery.
2. 
Wait one minute. This time is required for the back-up power supply in the air bag diagnostic
monitor to completely drain. The system is now disarmed.
3. 
If you are disarming the system with the intent of testing the system, do not! The SRS is a sensitive, complex
system and should only be tested or serviced by a qualified automotive technician. Also, specific tools are
needed for SRS testing.
ARMING THE SYSTEM Connect the positive battery cable.
1. 
Connect the negative battery cable.
2. 
Stand outside the vehicle and carefully turn the ignition to the RUNposition. Be sure that no part of
your body is in front of the air bag module on the steering wheel, to prevent injury in case of an
accidental air bag deployment.
3. 
Ensure the air bag indicator light turns off after approximately 6 seconds. If the light does not
illuminate at all, does not turn off, or starts to flash, have the system tested by a qualified automotive
technician. If the light does turn off after 6 seconds and does not flash, the SRS is working properly.
4. 
Chilton® Automotive Information Systems. © 2004 Thomson Delmar Learning. HOW TO USE THIS BOOK
668 SERVICE PRECAUTIONS 
						

							
HEATING AND AIR CONDITIONING
Blower Motor
REMOVAL & INSTALLATION
Exploded view of the blower motor mountingClick to enlarge
Exploded view of the blower motor and wheel (fan) assembly Click to enlarge
Without Air Conditioning Disconnect the negative battery cable.
1. 
Remove the air cleaner or air inlet duct, as necessary.
2. 
HEATING AND AIR CONDITIONING 669 
						

							If necessary, Remove the speed control module and the washer fluid reservoir.
3. 
To remove the blower motor, first disconnect the electrical wire harness plug ...... then remove the blower motor cooling tube from the motor
Disconnect the wire harness connector from the blower motor by pushing down on the connector tabs
and pulling the connector off of the motor.
4. 
Disconnect the blower motor cooling tube at the blower motor.
5.  HOW TO USE THIS BOOK
670 REMOVAL & INSTALLATION 
						

							Remove the blower motor attaching screws and the washer fluid reservoir ...
... then slide the blower motor from the housing. Take care to not damage the blower wheel (arrow)
Remove the 2 screws attaching the blower motor and wheel to the heater blower assembly.
6. 
Holding the cooling tube aside, pull the blower motor and wheel from the heater blower assembly and
remove it from the vehicle.
7. 
Remove the blower wheel push-nut and/or clamp from the motor shaft and pull the blower wheel
from the motor shaft.
8. 
To install: Install the blower wheel on the blower motor shaft.
9. 
Install the hub clamp and/or push-nut.
10. 
Holding the cooling tube aside, position the blower motor and wheel on the heater blower assembly
and install the 2 attaching screws.
11. 
Connect the blower motor cooling tube and the wire harness connector.
12. 
Install the vacuum reservoir on the hoses with the 1 screws.
13. 
If removed, install the speed control module and the washer fluid reservoir.
14. 
Install the air cleaner or air inlet duct, as necessary.
15. 
Connect the negative battery cable and check the system for proper operation.
16. 
With Air Conditioning Disconnect the negative battery cable.
1. 
In the engine compartment, disconnect the wire harness from the motor by pushing down on the tab
while pulling the connection off at the motor.
2. 
Remove the air cleaner or air inlet duct, as necessary.
3. 
If necessary, remove the solenoid box cover retaining bolts and the solenoid box cover.
4. 
Disconnect the blower motor cooling tube from the blower motor.
5. 
Remove the blower motor mounting plate attaching screws and remove the motor and wheel assembly
from the evaporator assembly blower motor housing.
6. 
Remove the blower motor hub clamp from the motor shaft and pull the blower wheel from the shaft.
7. 
To install: Install the blower motor wheel on the blower motor shaft and install a new hub clamp.
8.  HOW TO USE THIS BOOK
REMOVAL & INSTALLATION 671 
						

							Install a new motor mounting seal on the blower housing before installing the blower motor.
9. 
Position the blower motor and wheel assembly in the blower housing and install the attaching screws.
10. 
Connect the blower motor cooling tube.
11. 
Connect the electrical wire harness hard shell connector to the blower motor by pushing into place.
12. 
If removed, position the solenoid box cover into place and install the 2 retaining screws.
13. 
Install the air cleaner or air inlet duct, as necessary.
14. 
Connect the negative battery cable and check the blower motor in all speeds for proper operation.
15. 
Blower Motor Resistor
REMOVAL & INSTALLATION Disconnect the negative battery cable.
1. 
Disconnect the wire connector from the resistor assembly.
2. 
Remove the 2 screws attaching the resistor assembly to the blower or evaporator case and remove the
resistor.
3. 
Installation is the reverse of the removal procedure. Check the blower motor for proper operation in
all blower speeds.
4. 
View of the blower motor resistorClick to enlarge
Heater Core
REMOVAL & INSTALLATION
1991-94 Models HOW TO USE THIS BOOK
672 Blower Motor Resistor 
						

							Exploded view of the 1991-94 heater core assembly
Click to enlarge
Disconnect the negative battery cable. Allow the engine to cool down. Drain the cooling system to a
level below the heater core fittings on the firewall.
1. 
CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and
are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove
fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless
it is contaminated or several years old. HOW TO USE THIS BOOK
REMOVAL & INSTALLATION 673