2000 Ford Mustang Gt 4.6

Misti

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Jun 23, 2019
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Doniphan Mo
I have noticed that my Fan is Not kicking on. I decided to look into the problem and after testing with a multimeter. I have this black box in which contains a 30 v fuse. The fuse is good. The black box with the car on or off does not show it's working. I don't know what all this runs but I know it does link up to the fan! How do i correct the problem but where do I start on this issue.
I have attached 2 pictures of this box.

I would appreciate any help with this.

Thanks Misti May
 

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wmburns

SN Certified Technician
Aug 14, 2009
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The box in question is the circuit breaker (CB) for the LOW speed fan. If the CB were bad, THEN only the low speed fan would not work.

IMO if you are trying to trouble shoot the cooling fan, the first test should be to run the fan directly from battery. For the GT, test to confirm that the fan works on both low speed and high speed. There should be an obvious speed difference between low and high speed fan. There are 3 wires. RD/OG is the low speed. OG/LB is the high speed. BK is black for ground.

What to do next depends upon the results of this first test.

Have you confirmed IF fuse F1.1 is good with always on power coming in and out?

1999-2004 MY fuse panel schedule:

Does the cooling fan run IF the ECT sensor is disconnected at the intake?
 
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Misti

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Jun 23, 2019
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Doniphan Mo
Ok, Today I am going to do the first test. That is check low and high speed to the fan! I'm a little confused on how to do this exactly but I'm gonna get it figured out!
 

wmburns

SN Certified Technician
Aug 14, 2009
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Houston Texas
Does the cooling fan run IF the ECT sensor is disconnected at the intake?
Does the cooling fan run when the AC is on?

Hands down. The best and easiest way to fix this is by using an ODB2 scanner with bi-directional control. This makes it's possible to:
  • find out what the PCM "thinks" the value of the engine cool.ant temperature sensor (ECT).
  • find out what fan speed that the PCM wants.
  • Command the PCM to run the low speed fan
  • Command the PCM to run the high speed fan.
ForScan ODB2 scanner w ELM327 USB

The other options will need a test light and VOM to perform some detailed tests at the CCRM. Are you willing to perform the tests and post the results?

Or replace the CCRM on a guess since we know that the fan actually works on both speeds and fuse F1.1 is good.
 
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Misti

Member
Jun 23, 2019
12
1
13
38
Doniphan Mo
Does the cooling fan run when the AC is on?

Hands down. The best and easiest way to fix this is by using an ODB2 scanner with bi-directional control. This makes it's possible to:
  • find out what the PCM "thinks" the value of the engine cool.ant temperature sensor (ECT).
  • find out what fan speed that the PCM wants.
  • Command the PCM to run the low speed fan
  • Command the PCM to run the high speed fan.
ForScan ODB2 scanner w ELM327 USB

The other options will need a test light and VOM to perform some detailed tests at the CCRM. Are you willing to perform the tests and post the results?

Or replace the CCRM on a guess since we know that the fan actually works on both speeds and fuse F1.1 is good.
I Actually just bought the CCRM and I'm planning on replacing this tonight! I'm Hoping this corrects the problem. But if this does not work then I will perform the test needed!
 

Misti

Member
Jun 23, 2019
12
1
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38
Doniphan Mo
I'm Super Excited! I changed the CCRM & That Fixed the problem! I cant believe it! And on the down side when I was putting my fender back on. I accidentally didnt put the black piece that goes in the fender / Well area in correctly So While driving.... it came down. MY Passanger tire ate and chewed it to pieces. Now I have to find another! I cant believe it!