Question about 1991 Ford Mustang

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Cooling fan inop

Need wiring diagram for cooling fan circuit, 2.3 w/fact. air

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  • Ford Master
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The cooling fan is a one speed motor. operates only with key on.
The integrated control module (ICM) and the engine computer control the fan.
on at 102 degree C (@ 230 F), off at 99 degrees C (@ 230 F).
You have 3 fusible links, 2 18 gage brown and on 20 gage dark blue providing power to the ICM. You should ahve 12 volts the pink/black wire, the black/orange wire and the yellow wire going into the ICM.

First, jumper 12 volts from the battery directly to the terminal on the motor where the dark blue wire goes. Make sure the black wire is grounded. If the fan works, check the items above.

I can sell you this Ford wiring diagram book for a 91 Mustang for $10 if you are interested.
please rate as solved if this helps you, thanks.

Posted on May 27, 2009

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1995 Lt1 Camaro cooling fans operate like this; Cooling fans (2 fans) come on 30 seconds after start up on high, stay on while driving, and turn off when brakes are applied. Stock car, no mods.


Did you have it checked for DTC'S - diagnostic trouble codes ? The cooling fans are controlled by the PCM - engine computer , with the use of three relays ,located in the under hood electrical center . Do you know how to do electrical testing ?
Relay Driven Dual Cooling Fan Diagnostics Looking at wiring diagrams i don't see any connection between the brakes an cooling fans . Checking for DTC'S an doing electrical testing of control circuits from the PCM , Power circuits from the fuse / relay box . Checking grounds an pulling relays ,check for corrosion .

Electric Testing Techniques You Need to Know

View wiring diagrams here http://www.bbbind.com/free_tsb.html

ECM Inputs and Outputs Diagnosis


Mar 30, 2017 | Cars & Trucks

1 Answer

The cooling fan of my 1988 Toyota Corrola 1600 model 4A-L stopped working.What to check for and also need a wiring diagram of the fan cooling circuit.


engine cooling fan motor spinning too slow
faulty thermostatic switch
it may have a relay in the engine bay cluster

interior cooling fan has a relay

air con system fault or out of gas
the switch has worn
or the fan motor itself is worn outc763809f-9bac-4820-b6e2-4f6be4e9d9aa.jpg

cooling-fan-1988-toyota-corrola-1600-w4vgydzrgsrxsct3kdkw5uvf-3-2.jpg

Nov 24, 2016 | Toyota Cars & Trucks

1 Answer

Need a wiring diagram of the 2 wires from the temp sending unit that controls the temp gauge and cooling fans on a 99 grand am gt. Need to see where they go They disappear behind the engine


The PCM regulates voltage to the coolant fan relays, which operate the fans. Refer to Engine Controls.

Engine Cooling Fan Description - Electric
The electric cooling fans are used to lower the temperature of the engine coolant flowing through the radiator. They are also used to cool the refrigerant (R-134a) flowing through the A/C condenser.
Operation
The electric cooling fan operates when the engine cooling temperature exceeds a certain value. The cooling fan on this engine is controlled by the PCM. The cooling fan has one speed. The PCM turns the cooling fan ON by grounding the coil of the cooling fan relay when certain conditions are met. When the A/C is requested, the cooling fan will also be turned ON.
Power for the cooling fan motors are supplied through Cool Fan #1 and Cool Fan #2 relays. The cooling fan relays are energized when current flows from the fuses in the Cell 23: Cooling Fan Controls , and through the relay coils to ground through the PCM. The Low Speed fans control circuit is grounded for low speed fans operation. During low speed fans operation, both fans run at a slow speed. The High Speed fans control circuit is grounded for high speed operation. During high speed fans operation, both fans run at high speed.
Important: When certain Diagnostic Trouble Codes (DTCs) are present, the PCM may command the cooling fans to run all the time. It is important to perform Powertrain On Board Diagnostic (OBD) System Check prior to diagnosing the engine cooling fans.
If a problem that involves the low speed cooling fan relay control circuit exists, DTC P0480 should set. If the problem affects the high speed cooling fan relay control circuit, DTC P0481 should set. A problem with the ECT sensor should set DTC P0117, P0118, P1114, or P1115. Any of these DTCs will affect cooling fan operation and should be diagnosed before using the Cooling Fan Diagnosis tables. The Cooling Fan Diagnosis tables should be used to diagnose the PCM controlled cooling fans only, if a DTC has not set.

The engine coolant temperature (ECT) sensor (3) is a thermistor, a resistor which changes value based on temperature, mounted in the engine coolant stream. Low coolant temperature produces a high resistance (100,000 ohms at -40°C) (-40°F), while high temperature causes low resistance (70 ohms at 130°C) (266°F).
The PCM supplies a 5 volt signal to the ECT sensor through a resistor in the PCM and monitors the terminal voltage. Since this forms a series circuit to ground through the ECT sensor, high sensor resistance (low temperature) will result in high PCM terminal voltage. When the resistance of the ECT sensor is low (high temperature), the terminal voltage will be drawn lower. This terminal voltage indicates engine coolant temperature to the PCM.
A hard fault in the ECT sensor circuit should set either a DTC P0117 or P0118. Remember, these DTCs indicate a malfunction in the engine coolant temperature circuit, so proper use of the DTC table may lead to either repairing a wiring problem or replacing the sensor, to properly repair a problem.

The engine coolant sensor is an input to the PCM , Two wire's both go to the PCM .An the PCM turns on the cooling fans !

DTC P0480 Cooling Fan Relay 1 Control Circuit
DTC P0481Cooling Fan Relay 2 Control Circuit
The Body Control Module (BCM) request the cooling fans. The BCM sends a Class 2 message to the PCM in order to enable the fans based on various inputs. Thebattery voltage travels to all three cooling fan relay coils. The PCM enables cooling fan relay #1 by providing the ground path. The PCM enables cooling fan relays #2 and mode control together by providing a ground path. The left and right cooling fans are connected in series. This will enable both fans on low speed when the fan #1 relay is energized. When all three fan relays are energized, both fans will operate at high speed. The high speed is possible because the fan relays are wired in a parallel circuit. When the PCM detects that certain DTCs are set, the PCM will enable the cooling fans.
The PCM will enable the engine cooling fans when certain Diagnostic Trouble Codes are set.

Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.
1
Did you perform the Instrument Cluster System Check?
--
Go to Step 2
Go to Instrument Cluster System Check
2
Turn the ignition switch to the ON position.
With the scan tool select Instrument Panel Cluster, Special Functions, Instrument Panel Cluster (IPC) gauges.
Perform the Coolant Gauge Sweep Test.
Does the coolant temperature gauge complete a full sweep when commanded?
--
Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls
Go to Step 3
3
Replace the instrument cluster. Refer to Instrument Cluster Replacement .
Did you complete the repair?
--
Go to Instrument Cluster System Check
--

Your best bet would be to take your vehicle to a qualified repair shop that knows how the system works . An has the tools to diagnose the problem .

Nov 13, 2016 | 1999 Pontiac Grand Am GT

2 Answers

FANS WONT COME ON ,,ALL FUSES,RELAYS AND ELECTRIC FAN MOTORS ARE NEW,,THERMOSTAT IS GOOD,,WHERE IS ELECTRIC FAN TEMP SENSOR LOCATION


op
why not post symptoms first and not a barrage of parts.
must we decode that to a symptom,. kinda hard right.

I will not guess. what is wrong, nor what is not working on your car. now what fans you are talking about, up to 4 fans on cars.

cab blower fan (wild guess blower is ok) and so is HVAC, ?
radiator fans
Condenser fan.

my wild guess to , engine over heats?????????
if yes, the scan it first. no not last FIRST.
it dont work like you think its not a 1988 Samurai.
sorry,
on modern cars, they got smarter, the engine goes
gee the PCM knows water temp why have a fan temp regulator.
hark , now it dont. (saves cash on useless parts)
but has a relay , (well until you have my car and the relay is now 100% electronic, called a huge transistor)
we've used this tech in industry for years, but car makers just learning how still.
i digress. but evolution and history helps diagnosis.
what is there?

Ill look for you, ive posted this 100s of times
the book is 4 bucks to see online. the real deal
lets look now.
XL-7 (the dash matters big time)
answering for , overheats engine, and fans on RAD dead.
(some are staged, PCM brains... now. and also chain ops based on if A/C is on or not) facts.
first I see 2 fans... ok.
the next page shows nice block diagram of the fan system
yup, NOT Simple.

ill post those words for you.
"The engine cooling fan system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the engine control module (ECM) to operate both fans together at low or high speeds. The cooling fans receive positive voltage from the cooling fan relays which receive battery positive voltage from the underhood fuse block.
During low speed operation, the ECM supplies the ground path for the low speed cooling fan relay which is fan 1 relay through the low speed cooling fan relay control circuit. This energizes the low speed fan relay coil, closes the relay contacts, and supplies battery positive voltage from the fan 1 fuse through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the series/parallel relay which is fan 2 relay, and the right cooling fan. The result is a series circuit with both fans running at low speed.
During high speed operation the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. The ECM grounds the high speed fan relay, which is fan 3 relay, and the series/parallel relay, which is fan 2 relay through the high speed cooling fan relay control circuit. This energizes the series/parallel relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the high speed fan relay coil is energized closing the relay contacts and provides battery positive voltage from the fan 2 fuse 1 on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.
When the request for fan activation is withdrawn, the fan may not turn OFF until the ignition switch is moved to the OFF position or the vehicle speed exceeds approximately 16 km/h (10 mph). This is to prevent a fan from cycling ON and OFF excessively at idle.
end quote.

i bet you didnt scan it , like 99.9 % of all posters here dont.
DTC Descriptors
DTC P0480: Cooling Fan Relay 1 Control Circuit
DTC P0481: Cooling Fan Relay 2 Control Circuit
DTC P0691: Cooling Fan Relay 1 Control Circuit Low Voltage
DTC P0692: Cooling Fan Relay 1 Control Circuit High Voltage
DTC P0693: Cooling Fan Relay 2 Control Circuit Low Voltage
DTC P0694: Cooling Fan Relay 2 Control Circuit High Voltage
Diagnostic Fault Information

is the ECT showing overheat, yes no?
if yes, it must operate a fan or 2.
the book even covers all tests for fans dead, in a large truth table.
both the FSM and alldata.com have that, its no secret ,its published in 4 major places.

lets back up
if the engine coolant is low (no that side tank the engine and rad)
the ECT will lie. if that happens the fans may not come one
that is because the ECT is useless measuring air, for water.
that water must touch ECT for ECT to work.
this is FIRST
then scan the ECT does it show overheating, IT must if it IS overheating. fix that next if it lies to you,(IR gun in hand)

The system has staged fans.
i cant find the trip points in my crappyy online pages.
but is like 225f then 250f trips. is my guess...
about. if the engine over heats, check fuses first then scan it.
it will simply tell you why its bad.
eg, fan1 output dead.
or if you hot wire a fan and its dead, then it is.
(only on cars with non modulated fans,,hot wire them,else not.)

now the link to the 4 buck real book.
the non dash XL7 (my guess) you this pick yourself... cant see car.
https://suzukipitstopplus.com/Products/10182-2007-xl7-service-manual.aspx

this is how it really works
the ECU has software that decide trip points for fans.
hard coded, this is. based on how hot it is and if A/C is on not.
its way smarter than 1988 and better.
the DTC errors can see an open line, shorted to ground or stuck 12v.(runs all time error)
(tells you relay is good or not)

25839272-0kjd5huq4lpr130nt243wle5-3-0.jpg no scanner no joy , sorry, tis a fact.....

25839272-0kjd5huq4lpr130nt243wle5-3-2.jpg

Aug 27, 2015 | 2007 Suzuki XL-7

1 Answer

How do I troubleshoot my 1993 Saturn sl1 the fan doesn't work so the car overheats, beings I'm a female, tired of depending on a am , please help


If you know for a fact the cooling fan is why the engine overheats, you would test the relay and the signal from the computer.
The relay gets power from the battery circuit and the key switch, and a ground signal from the computer when the fan is needed.
The engine temp sensor tells the computer how hot the engine is, and when it reaches 220 degrees the computer grounds the relay providing power to the fan motor.
You would need a meter or a test light and the wiring diagram for the circuit to find the problem.

Oct 03, 2012 | 1993 Saturn SL

1 Answer

Electrical


The radio and a/c are on two different circuits other than both being powered thru the key switch. But they both share the same ground connections.
Its possible the two problems are not connected.
I would check the ground circuits for the radio and the blower motor. You may need a shop manual to find the wiring diagrams you will need.
On import cars, the blower motor speed is usually controlled by a resistor in the ground circuit. So if that ground is not good, the fan will run thru the relay but not thru the resistor. The high blower relay bypasses the resistor.

Aug 02, 2012 | 1989 Nissan Maxima

2 Answers

My 1995 Lumina is overheating all the time can only drive it a few blocks before heat gauge goes to the right all the way and hot light comes on. Had thermostat replaced and it seemed to help..for a...


When the heat gauge shows hot and the hot light comes on the cooling fans must come on therefore there is a problem with the fans. The fuses been replaced so that is ok just check if it is not blown again indicating a short circuit in the fans. If that is OK check the wiring leading to the motor if it is not disconnected somewhere. Look on the engine where the fan heat sensor is by following the wires from the fan and check the connection. Change the fan heat sensor as last resort.

May 23, 2017 | 1995 Chevrolet Lumina

2 Answers

Cooling fan is not coming on at all how do i wire it up to come on when car is started and stops when car is turned off


Here is a wiring diagram of how you should by-pass that cooling fan by using a toggle switch, and you can get a fuse holder and use a 30 amp fuse instead of a 30 amp circuit breaker, but you should use the circuit breaker since you are no longer using a relay, and if there is a voltage spike the circuit breaker will reset itself, and a fuse will blow out and you will have to change it. Most auto parts stores will carry the 30 amp toggle switch and circuit breaker, also be sure to use 10 ga. wire and do not forget the wire connectors that you will need to attach the wires to the toggle switch, the circuit breaker, and to the battery as well as the connection to the cooling fan wires.

This wiring diagram is very basic and you should be able to follow it with little difficulty, and you should also dis-connect the cooling fan at the wiring connector to the cooling fan and connect the by-pass wiring directly to the cooling fan motor so that you do not run voltage back through the stock system. Let me know if you require further assistance.


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Jun 04, 2010 | 1992 Pontiac Bonneville

2 Answers

I have a 94 olds cutlass cierra and the fans dont work


Check fuses, relays, the hook fan straight to batt power with jumper if fan is inop replace. If it works find your wiring problem.

Sep 21, 2009 | 1994 Oldsmobile Cutlass Ciera

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