1997 Accord both fans not working
#1
07-14-2011, 01:06 PM
1997 Accord both fans not working
Hello everyone. I have a problem with my fans not turning on it's for a 97 accord lx f22b2 4 cylinder. These are the things that have been done or changed: Radiator Fan Relay, Two fuse under dash and both A, B Fan Switch. I also ran the trouble shooting instructions in the workshop manual for non operation of both fans and everything seem to function fine, but even after doing all this fans has not turned on. Could it be that I need to change out these two plugs also?
"ECT sensor" Engine-Coolant-Temperature sensor is located roughly below the distributor. It has a plug with 2 wires. This sensor provides a coolant-temperature measurement for the ECM.
Lastly, there's another temperature sender near the ECT sensor. This one has only one wire and it provides the signal for the dashboard temperature gauge.
Any help is appreciated.
Paul
"ECT sensor" Engine-Coolant-Temperature sensor is located roughly below the distributor. It has a plug with 2 wires. This sensor provides a coolant-temperature measurement for the ECM.
Lastly, there's another temperature sender near the ECT sensor. This one has only one wire and it provides the signal for the dashboard temperature gauge.
Any help is appreciated.
Paul
#2
07-14-2011, 01:13 PM
Temp sensor A and temp sensor B are the only two sensors that will turn on the fans. The ECT and the sending unit send the temperature reading to the engine computer and the gauge in the instrument cluster respectively.
Can you tell us what is happening? Is the car overheating? Does it overheat when the car is moving, at a stop, or both?
If you turn on the a/c when the engine is running, do both fans turn on?
Can you tell us what is happening? Is the car overheating? Does it overheat when the car is moving, at a stop, or both?
If you turn on the a/c when the engine is running, do both fans turn on?
#3
07-14-2011, 09:19 PM
Temp sensor A and temp sensor B are the only two sensors that will turn on the fans. The ECT and the sending unit send the temperature reading to the engine computer and the gauge in the instrument cluster respectively.
Can you tell us what is happening? Is the car overheating? Does it overheat when the car is moving, at a stop, or both?
If you turn on the a/c when the engine is running, do both fans turn on?
Can you tell us what is happening? Is the car overheating? Does it overheat when the car is moving, at a stop, or both?
If you turn on the a/c when the engine is running, do both fans turn on?
Paul
#4
07-14-2011, 10:23 PM
That diagnostic is at the end of the tree for troubleshooting.
Lets take a couple of steps back. Unplug temp sensor A on the thermostat housing. Turn the key to the II position. Does the green wire have 12V to ground (use a valve cover bolt). Does the black wire have ~ zero resistance (closed circuit) to that ground.
You can try the same test on the pressure switch on the a/c hose. It is a pain to get to from the top. I thought it wasn't bad from under the car. Make sure the a/c switch inside the car is turned on and the blower inside the car is turned on and the key is in the II position. The red/wht wire should have 12V to ground and the blu/yel wire should be closed to ground.
Lets take a couple of steps back. Unplug temp sensor A on the thermostat housing. Turn the key to the II position. Does the green wire have 12V to ground (use a valve cover bolt). Does the black wire have ~ zero resistance (closed circuit) to that ground.
You can try the same test on the pressure switch on the a/c hose. It is a pain to get to from the top. I thought it wasn't bad from under the car. Make sure the a/c switch inside the car is turned on and the blower inside the car is turned on and the key is in the II position. The red/wht wire should have 12V to ground and the blu/yel wire should be closed to ground.
#5
07-15-2011, 01:47 PM
That diagnostic is at the end of the tree for troubleshooting.
Lets take a couple of steps back. Unplug temp sensor A on the thermostat housing. Turn the key to the II position. Does the green wire have 12V to ground (use a valve cover bolt). Does the black wire have ~ zero resistance (closed circuit) to that ground.
You can try the same test on the pressure switch on the a/c hose. It is a pain to get to from the top. I thought it wasn't bad from under the car. Make sure the a/c switch inside the car is turned on and the blower inside the car is turned on and the key is in the II position. The red/wht wire should have 12V to ground and the blu/yel wire should be closed to ground.
Lets take a couple of steps back. Unplug temp sensor A on the thermostat housing. Turn the key to the II position. Does the green wire have 12V to ground (use a valve cover bolt). Does the black wire have ~ zero resistance (closed circuit) to that ground.
You can try the same test on the pressure switch on the a/c hose. It is a pain to get to from the top. I thought it wasn't bad from under the car. Make sure the a/c switch inside the car is turned on and the blower inside the car is turned on and the key is in the II position. The red/wht wire should have 12V to ground and the blu/yel wire should be closed to ground.
Pressure switch red/white wire has 12V when grounded and blue/yellow has no resistance closed ground.
What should I do next? I know the fans still work when power is supplied directly.
Last edited by americapitalpaul; 07-15-2011 at 02:58 PM.
#6
07-15-2011, 03:11 PM
Those are normal readings.
The next place I would test are the electrical connectors for the two fan relays and the compressor relay. The radiator fan relay is in the engine bay fuse box. The a/c fan and a/c compressor relays are on the bracket by the driver's side of the radiator.
These relays have 4 pins. 2 pins that will have 12V when the key is in the II position. 1 pin will be closed to ground at all times. The last pin will be open or closed to ground.
You can see the wires on the two fan relays near the radiator. Turn key to II position.
A/C fan:
wht and yel/wht 12V
blu/yel grounded
grn open/closed to ground depending on a/c switch inside the car.
A/C Compressor
wht and blk/yel 12V
red grounded
red/blu open/closed to ground by the ECU.
For the radiator fan in the fuse box, you can't see the wire colors, but you should be able to tell us if you have 2 pins with 12V, 1 grounded all the time, and one that is grounded or not grounded. The a/c switch inside the car will ground or not ground this wire.
The next place I would test are the electrical connectors for the two fan relays and the compressor relay. The radiator fan relay is in the engine bay fuse box. The a/c fan and a/c compressor relays are on the bracket by the driver's side of the radiator.
These relays have 4 pins. 2 pins that will have 12V when the key is in the II position. 1 pin will be closed to ground at all times. The last pin will be open or closed to ground.
You can see the wires on the two fan relays near the radiator. Turn key to II position.
A/C fan:
wht and yel/wht 12V
blu/yel grounded
grn open/closed to ground depending on a/c switch inside the car.
A/C Compressor
wht and blk/yel 12V
red grounded
red/blu open/closed to ground by the ECU.
For the radiator fan in the fuse box, you can't see the wire colors, but you should be able to tell us if you have 2 pins with 12V, 1 grounded all the time, and one that is grounded or not grounded. The a/c switch inside the car will ground or not ground this wire.
#7
07-16-2011, 06:40 PM
Those are normal readings.
The next place I would test are the electrical connectors for the two fan relays and the compressor relay. The radiator fan relay is in the engine bay fuse box. The a/c fan and a/c compressor relays are on the bracket by the driver's side of the radiator.
These relays have 4 pins. 2 pins that will have 12V when the key is in the II position. 1 pin will be closed to ground at all times. The last pin will be open or closed to ground.
You can see the wires on the two fan relays near the radiator. Turn key to II position.
A/C fan:
wht and yel/wht 12V
blu/yel grounded
grn open/closed to ground depending on a/c switch inside the car.
A/C Compressor
wht and blk/yel 12V
red grounded
red/blu open/closed to ground by the ECU.
For the radiator fan in the fuse box, you can't see the wire colors, but you should be able to tell us if you have 2 pins with 12V, 1 grounded all the time, and one that is grounded or not grounded. The a/c switch inside the car will ground or not ground this wire.
The next place I would test are the electrical connectors for the two fan relays and the compressor relay. The radiator fan relay is in the engine bay fuse box. The a/c fan and a/c compressor relays are on the bracket by the driver's side of the radiator.
These relays have 4 pins. 2 pins that will have 12V when the key is in the II position. 1 pin will be closed to ground at all times. The last pin will be open or closed to ground.
You can see the wires on the two fan relays near the radiator. Turn key to II position.
A/C fan:
wht and yel/wht 12V
blu/yel grounded
grn open/closed to ground depending on a/c switch inside the car.
A/C Compressor
wht and blk/yel 12V
red grounded
red/blu open/closed to ground by the ECU.
For the radiator fan in the fuse box, you can't see the wire colors, but you should be able to tell us if you have 2 pins with 12V, 1 grounded all the time, and one that is grounded or not grounded. The a/c switch inside the car will ground or not ground this wire.
A/C Fan
wht and yel/wht had V reading. Something is draining battery by the way.
blu/yel grounded No resistance good
grn open/closed to ground depending on a/c switch inside the car. This wire is constantly getting power for some reason. It is also checking fine with everything under fuse box with the exception of green wire which the a/c switch controls is also getting power constantly. What could cause this to happen? Thanks for the replies PAHonda.
#8
07-16-2011, 08:23 PM
Tell us more about the battery drain, like how long it takes to drain the battery. Are any lights not turning off.
Make sure the ignition switch is turned off. Unplug temp switch A on the thermostat housing. Use a piece of wire to bridge the two pins the electrical connector, then turn the key to the II position? Do both radiator fans turn on?
That green wire is kind of tricky, because it is hooked up to the ECU. I don't know what the ECU does to that wire. Even if it has voltage, you should still be able to test for open/closed to ground.
If you have that shop manual, the inputs for the radiator control module are shown on page 22-19. I would give that a shot.
The other item you can test is the diode (it has two pins). If you test the diode itself you should get two different readings depending on which pin of the volt meter is touching pin #1. Zero resistance or infinite resistance. So use red on the left, black on the right, check resistance. Then black on the left, red on the right, check resistance. The location in way up under the driver's side of the dash. It will have a green and a red/white wire going to it. See page 22-4 for diode location.
Make sure the ignition switch is turned off. Unplug temp switch A on the thermostat housing. Use a piece of wire to bridge the two pins the electrical connector, then turn the key to the II position? Do both radiator fans turn on?
That green wire is kind of tricky, because it is hooked up to the ECU. I don't know what the ECU does to that wire. Even if it has voltage, you should still be able to test for open/closed to ground.
If you have that shop manual, the inputs for the radiator control module are shown on page 22-19. I would give that a shot.
The other item you can test is the diode (it has two pins). If you test the diode itself you should get two different readings depending on which pin of the volt meter is touching pin #1. Zero resistance or infinite resistance. So use red on the left, black on the right, check resistance. Then black on the left, red on the right, check resistance. The location in way up under the driver's side of the dash. It will have a green and a red/white wire going to it. See page 22-4 for diode location.
#9
07-17-2011, 02:19 AM
The battery drains slowly losing about 7V over night. I will check lights tomorrow.
Both fans run when wires are bridged.
Now I'm kinda learning about electrical so if you would explain to me how I would check for open/closed to ground and how it should read if it was open or closed.
I have ran the control module test as explained in the manual and everything seemed fine. Maybe I missed something, I'll probably recheck everything over.
I have a multimeter is it possible to test diode with that and what would I set it on?
Both fans run when wires are bridged.
Now I'm kinda learning about electrical so if you would explain to me how I would check for open/closed to ground and how it should read if it was open or closed.
I have ran the control module test as explained in the manual and everything seemed fine. Maybe I missed something, I'll probably recheck everything over.
I have a multimeter is it possible to test diode with that and what would I set it on?
#10
07-17-2011, 08:29 AM
Think of open/closed as connected/disconnected. You can use your volt meter to test this using two settings. Resistance or open/closed setting.
1. Resistance is a setting on every multimeter. Resistance is how well a metal conducts electricity. Copper has very low resistance, as does aluminum and iron metal. If your resistance between two wire ends is close to zero ohms, then those two wires are closed. If the resistance is infinity (same reading you get on the volt meter when the wires do not touch each other), then those two wire are open.
2. There is a diode or open/closed test on some volt meters where the meter will beep when the circuit is closed, or not beep when the circuit is open. The meter is basically doing the same test as resistance, it is just beeping when the circuit can conduct any electricity.
A diode is an electrical component that conducts electricity in only one direction. Imagine that a diode is in the middle of the wire and will conduct electricity from left to right. If you touch the + volt meter lead on the left and the - volt meter lead on the right, the wire would test as closed. If you switched the volt meter leads, then the wire would read open.
You can use either resistance or open/closed setting on the volt meter to do these tests.
1. Resistance is a setting on every multimeter. Resistance is how well a metal conducts electricity. Copper has very low resistance, as does aluminum and iron metal. If your resistance between two wire ends is close to zero ohms, then those two wires are closed. If the resistance is infinity (same reading you get on the volt meter when the wires do not touch each other), then those two wire are open.
2. There is a diode or open/closed test on some volt meters where the meter will beep when the circuit is closed, or not beep when the circuit is open. The meter is basically doing the same test as resistance, it is just beeping when the circuit can conduct any electricity.
A diode is an electrical component that conducts electricity in only one direction. Imagine that a diode is in the middle of the wire and will conduct electricity from left to right. If you touch the + volt meter lead on the left and the - volt meter lead on the right, the wire would test as closed. If you switched the volt meter leads, then the wire would read open.
You can use either resistance or open/closed setting on the volt meter to do these tests.
Last edited by PAhonda; 07-17-2011 at 01:34 PM.