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Cooling fans not A/C working at idle.

Started by Mrwrench2, September 30, 2018, 11:11:48 PM

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Mrwrench2

Hey guys! First post here.

Just bought a 2010 SHO, and recently ran into an issue.

When you start the car, and turn the air conditioning on, the A/C compressor will run briefly (5-10 seconds) and then disengage. When revving the engine, the A/C will work intermittently.

Also, neither radiator fan comes in when the A/C is switched on. If you turn the climate control on, the fans seem to work every once in awhile but kind of have a mind of their own. 

If you do not press the accelerator, the engine temperature will continue to rise well past the point where the fans should kick on (3/4 on the temp gauge) and at that point, I turn the car off.

I've read about burping the coolant, and will be attempting that in the morning, but this issue is strange and has me somewhat baffled. What's responsible for sending the turn on signal for the fans on our cars?

I also read about an AC pressure switch causing similar issues. Any advice there? Thanks in advance!

SHOdded

Welcome!  How many miles on your SHO?  If neither fan runs at all, and the coolant is burped, then the fans are most likely toast.  At least the pass side fan should run without climate control on when temps are above the set point.

I would check the connectors at the fan module for dirt/rust/corrosion/shorting.  Clean up the terminals, add a dab of dielectric, reconnect.  Also check the fan fuse #28 in the underhood fuse box, tho rarely at fault, may be dislodged, corroded or actually bad.
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

Mrwrench2

Car has 139,000 miles on it. It's strange, because they will both work fine at complete random times, but neither will ever come on when you command the A/C compressor on. Connections are clean and free of corrosion.

SHOdded

Randomness indicates a high probability of an error within the fan control module.  Which means, practically speaking, it is time to replace the fans.  Motorcraft highly preferred, aftermarket can be hit/miss.
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

Mrwrench2

Thanks for your quick reply, I'll see what I can find as far as OEM fans go!

Mrwrench2

Update:

After using the how to on burping the cooling system, fans will always engage as long as the AC isn't turned on (IE climate control off, or climate control on heat with no A/C compressor use)

But when you turn the A/C on, fans will no longer work, compressor short cycles, and they won't come back on again until next restart.

SHODDD, I'm thinking that it's more than likely the control module on the fan itself. Still thinking so?

SHOdded

Do both fans turn on when a/c is off?  Full speed for both?  Then yes, still fans/fan module.

There COULD be an A/C related problem otherwise, such as in the high pressure switch.  I do not recall if the switch has failed on a SHO before or not, but that would be a place to start.  Along with verifying A/C hi/lo pressures.  I do know the compressor has had to be replaced on occasion on the SHO.
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

ZSHO

If both of your Fans are running constantly with A/C OFF you may be able to "Troubleshoot" it with the below Diagram or try swapping out both your relays from
(BJB). 
Diagram @ Bottom of page. Z

https://www.ecoboostperformanceforum.com/index.php/topic,6370.0.html


2013 Performance Package SHO| Livernois Custom Methanol Tune|3-Bar Map|Reische-170-Stat|Full Race Tial-10psi BOV in Black|PPE-Gloss Black Hot Pipes|EPP Dual Intake in Gloss Black|PPE Catted DP|Corsa Sport Cat Back Exhaust|H&R Sport-Springs|CFM Performance Billet Valve Cover Breather In Gloss Black|Llumar 20%Ceramic window Tint|MSD Ignition Coils in Black|Extreme Roof Spoiler|Redline Fluids all around|Gearhead Intercooler|First-SHO With Direct Port Alky-VP-M1-100%-Methanol Injection|LMS-Custom-Dyno-Tuned @ 415whp-465wtq| Best Trap Speed of 115.54 mph|

Mrwrench2

After taking a look at the radiator fan and 3 plug relay mounted on the fans, both are brand new from Ford.

The problem remains, if you dont turn on the A/C, fans work fine when they're supposed to. Turn on the A/C, The fans wont operate and neither will the A/C compressor after a couple cycles. Weirdest issue I have ever faced on a car.

SHOdded

Do a KAM reset by pulling the neg batt cable for 40+ minutes.  This is to see if it is an electrical gremlin in one of the modules.

Verify the CCAs on the battery with a digital tester like the Solar BA7.  Battery may be old and a/c just too much load.

Check the wiring harness that runs atop the radiator for damaged wiring.

Has the car been in any accidents?
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

Mrwrench2

#10
The car was in a front end accident before. Radiator and AC condenser are still original, but the radiator fans were replaced very recently (it's obvious due to condition of plastic).

Battery is 9 months old and has sufficient CCA (verified with tester)

I visually inspected/shook the wiring leading to the fan control module on the back of the fans and all looks ok and no change in how the fans operate. I'm going to reset the KAM and leave the battery terminal off for some time and see if that mitigates the issue.

Mrwrench2

***SOLVED!***

Thanks for all your input!

Turns out that it had an incorrectly charged A/C system and was carrying an excessive amount of oil in it.

Evacuated and recharged the A/C system and the fans are operating as they should. The pressure switch was doing it's job the whole time.

Hope this is helpful for other users in the future!

SHOdded

Kewl!  Back-to-basics wins the day.  Glad it wasn't anything "more" LOL.
2007 Ford Edge SEL, Powerstop F/R Brake Kit, TXT LED 6000K Lo & Hi Beams, W16W LED Reverse Bulbs, 3BSpec 2.5w Map Lights, 5W Cree rear dome lights, 5W Cree cargo light, DTBL LED Taillights

If tuned:  Take note of the strategy code as you return to stock (including 3 bar MAP to 2 bar MAP) -> take car in & get it serviced -> check strategy code when you get car back -> have tuner update your tune if the strategy code has changed -> reload tune -> ENJOY!

Mrwrench2

Yea, with the amount of dye that it had in it, I'm surprised that the A/C was working at all.