Condenser/Radiator Fan Module are not working

Tiny
RONALD DEVOLD
  • MEMBER
  • 2006 MAZDA 3
  • 2.3L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 273,856 MILES
Start engine and turn on A/C, fan not working. The fan has a module. There are three wires going to the module. Red wire (constant power), black wire (constant ground), purple wire (guessing signal). No readings at signal wire. The module has two wires coming out going to the fan motor. Unplugged the harness that is located above the radiator, and I ran power and ground to the two wires (black (-) and white (+). Fan comes on. But when connected I am getting voltage to both the black and white wires going to the fan motor. So, I'm guessing the control module is bad because I don't know what reading I should be getting coming from the purple wire. And, what's the purpose of the green wire? I have attached a pic of the actual module on my car.
Thursday, June 23rd, 2022 AT 7:22 AM

5 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,323 POSTS
It sounds like the control module is bad which is common. Here are the cooling fan wiring diagrams so you can see how the system works. Here is a factory procedure:

Cooling Fan Control System Inspection
1. Verify that the battery voltage is more than 12.4 V.
- If the battery voltage is less than 12.4 V, charge the battery or connect the external power supply.

2. Connect the M-MDS and access ECT PID.
3. Turn A/C switch to off.
4. Verify ECT PID is less than 98 °C 209 °F.
- If ECT PID more than 98 °C 209 °F), inspect ECT sensor and related wiring harnesses.

5. Verify that the cooling fan does not operate with ECT PID is less than 98 °C 209 °F while the ignition switch is ON.
- If the cooling fan operates, inspect for following parts and related wiring harnesses:
- ECT sensor
- A/C switch
- A/C refrigerant pressure switch (High/low pressure)
- A/C refrigerant pressure switch (Medium pressure)
- VSS
- A/C magnetic clutch
- Fan control signal circuit (between fan control module terminal B and PCM terminal 1W)
- If the all items are normal, replace fan control module.

6. Verify the cooling fan operates while the A/C switch to ON with the ignition switch at ON position.
- If the cooling fan does not operate, inspect for following:
- A/C switch
- A/C refrigerant pressure switch (High/low pressure)
- Fan control module power supply circuit
- Fan control module GND circuit- Fan control signal circuit (between fan control module terminal B and PCM terminal 1W)
- If the all items are normal, replace fan control module.

7. Verify that the cooling fan operates with following table.
- If the cooling fan operation is not specified, inspect for following:
- A/C refrigerant pressure switch (Medium pressure)
- If the A/C refrigerant pressure switch (Medium pressure) is normal, replace fan control module.

8. Turn A/C switch to off.
9. Start the engine and idle it.
10. Verify that the cooling fan operating speed increases relative to ECT PID increases.
- If the cooling fan speed does not increase inspect following:
- ECT sensor (characteristic)
(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION[LF L3)
- Fan control signal circuit (between fan control module terminal B and PCM terminal 1W)
- If the all items are normal, replace fan control module.

Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.
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Friday, June 24th, 2022 AT 9:05 AM
Tiny
RONALD DEVOLD
  • MEMBER
  • 107 POSTS
So, I noticed on the diagram that the engine temperature sensor controls the fan. I replaced the sensor and the thermostat, and the fan came on immediately after starting the engine and the temperature gauge never moved. I inspected the harness and repaired the harness, and the fan didn't immediately come on the gauge is working. After that I attempted to. Charge the system but the Freon leaked out. I put pressurized air through the system and noticed air leaking from the evaporator, I'm quite sure it was leaking from the expansion valve because I had the bolts pretty type. Now I'm thinking I have to replace the evaporator core which is attached to the A/C heater assembly under the dash. Is there any other way to do a leak test on the evaporator?
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Saturday, July 2nd, 2022 AT 9:51 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,323 POSTS
Yes, check out this video, it will show you what to do:

https://youtu.be/yrhWKlQEPWw

let me know what you find.
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Saturday, July 2nd, 2022 AT 2:53 PM
Tiny
RONALD DEVOLD
  • MEMBER
  • 107 POSTS
I replaced the temperature sensor and the thermostat. I noticed a wire was broken on the harness. I repaired the wire and installed the new sensor. After a week, the car starts to idle rough, and the temperature gauge will drop and then slowly rise back up. The temperature sensor code came back. I cleared the code, and the car ran fine for a few hours and back to running rough and hard shifting.
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Thursday, July 7th, 2022 AT 3:01 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 48,323 POSTS
It sounds like you may have a blown head gasket, to be sure let's use this guide to confirm the issue:

https://www.2carpros.com/articles/head-gasket-blown-test

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down this guide and report back.
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+1
Saturday, July 9th, 2022 AT 9:42 AM

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