03 RADIATOR FAN WONT TURN ON

[JaedonMustang03]

I have a brand new fan, new temperature switch. what could be the reason my car radiator fan doesn’t turn on? could it be the control switch under the passenger wheel well? could it be a fuse from the power distribution box? could it be bad wiring? how do I find out?
thank you!

 

[wmburns]

So what about all of the questions and tests given in your other thread?

What about the power and ground test at the cooling fan plug?

Or did you replace the cooling fan without doing any tests?

03 MUSTANG RADIATOR FAN NOT WORKING

03 MUSTANG RADIATOR FAN NOT WORKING

I have a 03 mustang, just can’t figure out what the issue is on why my radiator fan isn’t working. I have checked the 50A fuse, replaced the coolant temperature sensor and I still haven’t found the solution. when I turn the car ac on it blows warm, but clicks over like it wants to turn the fan...

www.stangnet.com

Everything that is needed to trouble shoot this problem was given in the previous thread. If we now "assume" that the fan is good, then it has to be a power or ground problem of some description. Unless you are willing to do some tests and post the results, we can't really help you.

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If you insist on using the "parts changing" trouble shooting method and you are certain that the fuses are good, then replace the CCRM.

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But be warned that IF there's a ground problem, ECT problem, wiring problem, PCM problem this expensive part may not fix the complaint.

 

[JaedonMustang03]

Thank you , it’s was the radiator fan relay. once again, I connected my fan to the battery with “alligator” jumper cables and it worked which narrowed my options to a 50A fuse , the radiator fan relay or wiring issue. I check the fuses(via manual) they were fine. I didn’t bother with the wiring because if it was that issue , that’d be more than my expenses as well as I could return the fan relay (which would be easier than replacing a ton of wires) so I jumped straight to the radiator fan relay which is located under the passenger side wheel well. bolted down by a 5.5mm bolt(2)

 

[wmburns]

It might help others with a bad CCRM if you were to write up more about your experiences (good and bad) with the job. How long did it take? Is it an easy or hard DIY job? Was the part expensive and where did you get it?

 

[JaedonMustang03]

It might help others with a bad CCRM if you were to write up more about your experiences (good and bad) with the job. How long did it take? Is it an easy or hard DIY job? Was the part expensive and where did you get it?

Took about an hour. easy DIY job. I got the part for $100 brand new from a local auto parts store.

 

[JaedonMustang03]

I got the fan to work when my ac is on but it doesn’t work when I drive even after the engine gets “normal” temperature. I replaced the coolant temp sensor. what could the issue be?

 

[tsemmett]

You really should be "bothering with the wiring" at this point. CCRMs and Temp sensors are pretty simple devices; they don't fail that easily. I personally replaced a CCRM on mine when dealing with an A/C clutch that wouldn't come on, and it turned out to be the clutch connector (a $14 part). I've also had issues with my fan connector that caused the high speed fan to fail to start.

Check the fan plug first; in my case one of the wires had started to back out of the connector (the rubber seal on the back was out just enough to break the circuit). But, it's also a high amperage circuit, so damaged/burned/etc fan plugs aren't that uncommon.

If the connector is good, get a multimeter and start testing the wiring. Even a simple tone test would be helpful. Some information that might help:

Wires at the Fan plug:
Black - Ground
Red/Orange - Low Speed +12V
Orange/Light Blue - High Speed +12V

Wires at the CCRM:
Red/Orange (2 wires, should be pins 1 and 2) - Power out to Low Speed Fan
Orange/Light Blue (also 2 wires, should be pins 6 and 7) - Power out to High Speed Fan
Yellow/Black (again, 2 wires, pins 3 and 4) - Power in from Junction Box (50A fuse under hood) for fans

Check for continuity from the CCRM to the Fan (on the Red/Orange and Orange/Light Blue wires at each end).
Check for power at the CCRM (on the Yellow/Black wires).
With the engine hot and running, check for power at the fan plug (low or high should be on, but not both).

This definitely can be a little time consuming, and annoying, but it's difficult to repair this sort of issue without proper diagnosis, so the time is worth it.

 

[wmburns]

I got the fan to work when my ac is on but it doesn’t work when I drive even after the engine gets “normal” temperature. I replaced the coolant temp sensor. what could the issue be?

First. How fast were you driving? Are you aware that the fan is programmed to turn off when the car's speed is above 45 MPH?

Again. If you truly want to trouble shoot this issue there isn't a easier/faster way to answer all of the questions than using an ODB2 scanner. The information was previously given to you.

What is the system voltage? Remember that a low system voltage will make the ECT read higher. Which is another reason why it's necessary to cross check the ECT with the measured temperature of the T-stat housing.

But if you post the voltage across the ECT sensor it's possible to "look up" what the temperature is. But it will also be necessary to cross check the temperature of the T-stat housing. So let us know what the temperature of the T-stat housing is as well as the voltage across the ECT sensor.

Bottom line. The PCM works very hard NOT to run the fan unless it is needed. Soooooooooooooooooo is the motor actually over heating? If it's not actually overheating AND the fan is running with the AC on at idle IMO it's likely there's nothing wrong.