Cooling fans not working at all.

[Drifting in 808]

Ok, i checked all my fuses, checked my relay for my cooling fan and for some reason it is not working. i checked the motor by runing wires straight from the batt. and it worked. everyone says that when you turn your a/c on, its supposed to force the fans to come on. well when i turn it on, the fans do not come on at all. after runing the car for about 25 mins it started to overheat so i shut it down. I know the motor for the fan isn't bad. What are my possibilitys before i start buying stuff.Sorry i should have added this earlier, this is for a H22a from a 93 lude. Neither condensor fan or radiator fan comes on.

[BLUBB2]

Fan switch on thermostat housing.

[stretch JDM]

straight wire it to a toggle switch .but then be sure to cut it off while car is off.

[kellogg_racing_]

Ok, i checked all my fuses, checked my relay for my cooling fan and for some reason it is not working. i checked the motor by runing wires straight from the batt. and it worked. everyone says that when you turn your a/c on, its supposed to force the fans to come on. well when i turn it on, the fans do not come on at all. after runing the car for about 25 mins it started to overheat so i shut it down. I know the motor for the fan isn't bad. What are my possibilitys before i start buying stuff.

Only ONE fan is supposed to come on with the AC is switched on. So if your worried about only one coming one, that is what is supposed to happen. But blub beat me to it: it's more than likely the switch on the thermostat housing.

http://www.autozone.com/autozone/par...19129_32043_0_

Here's the part from Autozone. It's only like $24

[benjerman112]

Ok I have a guestion? My fans work like they should when the car is on but i've noticed that my friends car his fans will kick on after the car has been turned off? Mine dont do that.

[accord_f22a91]

Only ONE fan is supposed to come on with the AC is switched on. So if your worried about only one coming one, that is what is supposed to happen. But blub beat me to it: it's more than likely the switch on the thermostat housing.

http://www.autozone.com/autozone/par...19129_32043_0_

Here's the part from Autozone. It's only like $24

is this the same as the one that is located on front of the engine or is the one u are talking about more by the back

[James Matteu]

Fan Diagnostic Procedure

I have some experience in this area, my V6 thread.



How It Works:

The Radiator Fan Control Module receives input via two temperature switches: Engine Coolant Temperature Switch A and Engine Coolant Temperature Switch B.

Engine Coolant Temperature Switch A is open to ground below 106°C (223°F).
Engine Coolant Temperature Switch B is open to ground below 93°C (199°F).

The Radiator Fan Control Module receives independent input from Switch B.
Switch A not only provides input to the Radiator Fan Control Module, but also provides a ground to the Condensor Fan Relay.
The Condensor Fan Relay can be grounded by: Switch A, the Powertrain or Engine Control Module (PCM or ECM), or the A/C Circuit.
The Radiator Fan Relay can also be grounded by: Switch A, the Powertrain or Engine Control Module (PCM or ECM), or the A/C Circuit.
Both fan relays provide voltage directly to their respective fans; condensor and radiator.

So we're all on the same page: the fan on the passenger side (USDM) is the Radiator Fan, the fan on the driver side is the Condensor Fan, the temperature switch behind the distributor is Engine Coolant Temperature Switch A (ECT Switch A), the temperature switch next the to the exhaust header and on top of the thermostat housing is Engine Coolant Temperature Switch B (ECT Switch B), the Engine Coolant Temperature Sensor (ECT Sensor) looks different from the switches; see below.



I circled the ECT Switch B in yellow. I colored the ECT Sensor in red. I colored the ECT Sending Unit blue, this unit controls the temperature needle on your gauge cluster.

Fuses:

First be sure that you have no blown fuses. Numbers 21 and 34 in the under-hood fuse block are the ones you want to check.

Relays:

You need to make sure that there is sufficient continuity from the relays to their respective fans by grounding the circuit and verifying that the fans will come on.

Relay

1. Apply 12 volts across the inductor side of the relay while measuring resistance on the relay’s switch side to verify the relay’s switch side can make a good connection?

2. Measure resistance across the inductor side to be sure none of the windings are damaged. Remember, a weak inductor can result in a weak magnetic field for the switch.

Relay Connection

3. Verify there is no resistance between the relay’s inductor side’s ground connection and the chassis.

4. Verify there is no resistance between the relay’s inductor side’s voltage connection and the Radiator Fan Control Unit.

5. Verify there is no resistance between the relay’s switch side connection to the fan and the Radiator Fan connection.

6. Measure the switch side’s voltage connection to verify there actually 12-13.1 volts available for the Radiator Fan.

I think you get the idea; you want to repeat this sort of check on all connections until you find out where the voltage is getting lost.

An easy check for the wiring between the relay and fan: Jump the voltage and ground connections for the relay to simulate a closed switch and see if the Radiator Fan will come on.

Remember: the relay controls the fan, the Control Unit controls the relay, and the temp switches and temp sensors control the Radiator Fan Control Unit.

Motors:

Jump each motor individually to battery voltage to ensure proper function.

Sensors:

While the engine is cold, i.e. let the car sit over night; check the resistance across the sensor:

- between -4°F and 32°F, you should see between 5 and 20 ohms
- between 32°F and 104°F, you should see between 1 and 5 ohms

Then run the car for about 10 minutes or until you see the temperature needle rise. Check the resistance across the sensor:

- between 104°F and 176°F, you should see less than 1 ohm, but more than a tenth of an ohm
- over 176°F, you should see the ohms drop off to zero or float real close to it

Switches:

Now that the car is warm, check to make sure that both switches are open, i.e. no resistance between their contacts.

Radiator Fan Control Unit:

1. Be sure it's plugged in. Trust me, it happens.

2. If all else checks out. Swap with a known working unit and retest.

Circuit Diagrams:







Sources:
1997 Accord Electrical Troubleshooting Manual, Part Number 61SV405EL
1997 Accord Service Manual, Part Number 61SV405


You can thank me by leaving rep points.

[James Matteu]

Ok I have a guestion? My fans work like they should when the car is on but i've noticed that my friends car his fans will kick on after the car has been turned off? Mine dont do that.

Unless your buddy's car was overheating, it should not be doing that. The Timing Circuit will run the fans for an extended period of time (about 15 min.) after the car has been turned off if Temp Switch B (or Oil Temp Switch for the 5th Gen V6) is "seen" as being on by the Radiator Fan Control Unit.

I put parenthesis around seen 'cause the Radiator Fan Control Unit CANNOT differentiate between a short in the temp switch harness and an actual closed temp switch.

[accord_f22a91]

Unless your buddy's car was overheating, it should not be doing that. The Timing Circuit will run the fans for an extended period of time (about 15 min.) after the car has been turned off if Temp Switch B (or Oil Temp Switch for the 5th Gen V6) is "seen" as being on by the Radiator Fan Control Unit.

I put parenthesis around seen 'cause the Radiator Fan Control Unit CANNOT differentiate between a short in the temp switch harness and an actual closed temp switch.

what is the sensor on the
thermost radiator fan switch job or will that make the cars temperature go up after the car has been running for about ten minutes or can i b the ground to??

[James Matteu]

what is the sensor on the
thermost radiator fan switch job or will that make the cars temperature go up after the car has been running for about ten minutes or can i b the ground to??

Look at the first of my two posts, it literally answers all that you have asked. It has pictures too.

[kellogg_racing_]

is this the same as the one that is located on front of the engine or is the one u are talking about more by the back

It's on the front. The thermostat housing is what the upper radiator hose connects to.

[Drifting in 808]

i unplugged my fan switch near the thermo housing and the green female part of it was black, and the male side had a crack in the plastic. should both be changed? and if so, do they sell them together. Also even if i replace my fan switch, how do i get my condensor fan to come on at all if the a/c is runing. and is running a toggle switch a good option, because i dont got a lot of money to spend and want the best/cheapest way to go.

[James Matteu]

By far, the cheapest way to go is remove the connector from the temp switch and stick a paper clip in to jump one wire to the other. The Timer Circuit will see the engine warm at all times and run the fans accordingly.

If your fans still don't come on, then you have another issue and need to pull out the multimeter.

[Drifting in 808]

so where exactly am i jumping the wire to. or even better can u give a pic? the last ones you did were very helpful.that should be moved as a sticky.

[James Matteu]

i unplugged my fan switch near the thermo housing ...

Unplug the one I have highlighted RED in the photos I posted above, stick the paperclip in side with wires coming out.