Cooling Fan Not Working
#1
Cooling Fan Not Working
I have a 2006 V6. It recently has been overheating. The cooling fan doesn't appear to be turning on. I've tried turning the AC on max but the fan still doesn't turn on. I don't think it's a burnt wire issue.
I've inspected the fan plug and resistor and there are no signs of burning. I've also looked under the fuse box and see no signs of burning either at the pin receptacle or the wire underneath.
There is power to the high speed relay from both fuses (pins 87 (40A) and 86 (15A fuse)); and the output wire (pin 30) shows no resistance (no OL) between the pin and the plug. BUT when the AC is on high and the PCM should be establishing a ground at pin 85, no ground seems to exist, as evidenced by a test light giving NO light between the positive battery post and pin 85 AND when I test between pins 85 and 86 (which I believe is necessary to trigger the relay). I do however get a light between pins 87 and 30. I'm guessing if I hard-wired 87 and 30 the fan would run? So, my assumption is that the relay isn't being activated. The wiring, at least in the pictures, seems OK. What else could it be? Am I mistaken on how this should work? Am I missing something? Thanks for any advice.
I've inspected the fan plug and resistor and there are no signs of burning. I've also looked under the fuse box and see no signs of burning either at the pin receptacle or the wire underneath.
There is power to the high speed relay from both fuses (pins 87 (40A) and 86 (15A fuse)); and the output wire (pin 30) shows no resistance (no OL) between the pin and the plug. BUT when the AC is on high and the PCM should be establishing a ground at pin 85, no ground seems to exist, as evidenced by a test light giving NO light between the positive battery post and pin 85 AND when I test between pins 85 and 86 (which I believe is necessary to trigger the relay). I do however get a light between pins 87 and 30. I'm guessing if I hard-wired 87 and 30 the fan would run? So, my assumption is that the relay isn't being activated. The wiring, at least in the pictures, seems OK. What else could it be? Am I mistaken on how this should work? Am I missing something? Thanks for any advice.
#2
The Analog Admin!
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Welcome!
Have You Checked For Any DTC Codes?? Might Want To Check SJb as Well for Any Water Intrusion!
See This Link For Codes.
https://themustangsource.com/forums/...e-info-550470/
Related Thread!
https://themustangsource.com/forums/...g-help-541593/
Here is The Shop Manual Pdf. For The Cooling System And Wiring Diagram!
KC
Have You Checked For Any DTC Codes?? Might Want To Check SJb as Well for Any Water Intrusion!
See This Link For Codes.
https://themustangsource.com/forums/...e-info-550470/
Related Thread!
https://themustangsource.com/forums/...g-help-541593/
Here is The Shop Manual Pdf. For The Cooling System And Wiring Diagram!
KC
#3
Legacy TMS Member
Join Date: January 25, 2010
Location: Massachusetts
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welcome to the forum
I don't know all the specific details around this, but I believe there are some existing threads on here that might help ..... this is a common/familiar issue and I believe there are several fuses and relays involved ..... if the links that KC posted above don't get you there, try the "search" feature to see if you can find the existing threads
I don't know all the specific details around this, but I believe there are some existing threads on here that might help ..... this is a common/familiar issue and I believe there are several fuses and relays involved ..... if the links that KC posted above don't get you there, try the "search" feature to see if you can find the existing threads
#4
Welcome!
Have You Checked For Any DTC Codes?? Might Want To Check SJb as Well for Any Water Intrusion!
See This Link For Codes.
https://themustangsource.com/forums/...e-info-550470/
Related Thread!
https://themustangsource.com/forums/...g-help-541593/
Here is The Shop Manual Pdf. For The Cooling System And Wiring Diagram!
KC
Have You Checked For Any DTC Codes?? Might Want To Check SJb as Well for Any Water Intrusion!
See This Link For Codes.
https://themustangsource.com/forums/...e-info-550470/
Related Thread!
https://themustangsource.com/forums/...g-help-541593/
Here is The Shop Manual Pdf. For The Cooling System And Wiring Diagram!
KC
The service manual links you gave refers to the Powertrain Control/Emissions Diagnosis (PC/ED) manual. Do you have a link for that by chance?
Also, do you know if I could direct wire between pin 87 and 30 to test if everything from the fuse box to the fan is operable? I guess essentially bypassing the relay? Could I try for both high and low speed? Will doing so cause damage to the electrical system? Thanks for any input.
#5
The Analog Admin!
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The Dtc Codes Link is The Pc Section. A Code Reader That Also Pulls Body Codes Might Be Helpful! Sometimes Just Dtc Codes are Not The Whole Story!
https://themustangsource.com/forums/...e-info-550470/
KC
https://themustangsource.com/forums/...e-info-550470/
KC
#6
05stangkc - i can't figure out how to navigate the manual you attached. i've looked over the wiring diagram for the cooling fan and think i understand it.
so what i did was hardwire pins 87 and 30 for both the high and low speed fans. they both worked fine. so...i'm assuming that everything from the fuse box to the fan works as it should. that means there's no melted wires, burnt pins or bad plug.
there is a relay for the PCM itself but that must be working bc there is power at both the high and low speed relays via fuse F40.
my thought is that the problem can be only 1 of 2 things: the wires from the relays to the PCM are bad (LG-VT for high and DB for low) OR there's something wrong with the PCM itself bc it's failing to create a ground to activate the cooling fan relays.
how do i locate those wires and how can i test them? and how can i test the PCM? what else does it do so maybe i can check those functions? thanks
so what i did was hardwire pins 87 and 30 for both the high and low speed fans. they both worked fine. so...i'm assuming that everything from the fuse box to the fan works as it should. that means there's no melted wires, burnt pins or bad plug.
there is a relay for the PCM itself but that must be working bc there is power at both the high and low speed relays via fuse F40.
my thought is that the problem can be only 1 of 2 things: the wires from the relays to the PCM are bad (LG-VT for high and DB for low) OR there's something wrong with the PCM itself bc it's failing to create a ground to activate the cooling fan relays.
how do i locate those wires and how can i test them? and how can i test the PCM? what else does it do so maybe i can check those functions? thanks
Last edited by brian m1; 6/23/24 at 03:57 PM.
#7
The Analog Admin!
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If You Can Get Some Dtc or Body Codes The Shop Manual Takes You Through Diagnostics Though Sometimes You Need Additional Equipment At That Point. It Would At Least Point You In The Right Direction If Some Codes Popped Up. If You Don't Have a Code Reader Many Parts Houses Will Scan For Free. If You Can Hotwire Fans While Leaving Wiring intact That Could get You Down There.
KC
Here are Some Pdf's Which May Help in The Meantime!
The SJb Related Conector as Shown In The Cooling Wiring and The Pcm Connector Which Has The Fan Wiring.
KC
Here are Some Pdf's Which May Help in The Meantime!
The SJb Related Conector as Shown In The Cooling Wiring and The Pcm Connector Which Has The Fan Wiring.
#8
The Analog Admin!
Join Date: November 27, 2004
Location: Visalia Ca.
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#9
SUPERCHARGED RED ROCKET ------------------Master-Moderator
welcome to the forum
I don't know all the specific details around this, but I believe there are some existing threads on here that might help ..... this is a common/familiar issue and I believe there are several fuses and relays involved ..... if the links that KC posted above don't get you there, try the "search" feature to see if you can find the existing threads
I don't know all the specific details around this, but I believe there are some existing threads on here that might help ..... this is a common/familiar issue and I believe there are several fuses and relays involved ..... if the links that KC posted above don't get you there, try the "search" feature to see if you can find the existing threads
Go through each thread until you're able to locate exactly which threads address your particular issues...
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