2008 MKX heating up

[Neff22]

My 2008 MKX is overheating fans are not running at all. I replaced thermostat and then noticed fans are not working! Do I need to replace the fans?

[akirby]

Most likely. Try A/C on high - both fans should come on regardless of temp.

Edited October 7, 2015 by akirby

[Neff22]

Already did and they never came on. What about the fan module? Is that part of the fan assembly? Do I need to replace the whole assembly?

[enigma-2]

There are six elements that involved in the circuit. Wiring, relays, fuses, fan control module, cooling fan motor(s) & cooling fan resistor(s).

Electrically, the fans come off fuse #5 - 60 amp (w/o trailer tow pkg) -or- #5 & #6 - 40 amp ea. (with trailer tow pkg) in the battery junction box. For the tow pkg. both fuses are wired into one wire that leads to the fan module. It's a VT-GY insulation.

From the fuse(s), the circuit runs to the cooling fan module and then to the fans (one conductor that feeds in parallel with no trailer tow, or two separate conductors with trailer tow pkg.). The cooling fan module also takes an input from the power-train control module.

 

In the power-train emissions manual it talks about determining which codes are set (to determine if the fault is coming from the power-train control module or from somewhere else). Without knowing the codes, it gets very detailed as to how to trace the circuits by pulling the connectors and checking for voltage. Gets more complicated in that some vehicles have the relay wiring reversed on power and that would result in the fans running all the time when the engine is off.

 

With neither fan running I would check the fuse first (fuses if you have trailer tow pkg.) If OK, I would suspect the fan module as failing. The fan control module is part of the entire assembly. (One nice thing is that once you disconnect the wiring harness, the fan assemble is only attached with two bolts.

 

From the manual:

1. Remove the Air Cleaner (ACL) assembly. For additional information, refer to Section 303-12 .
2. If equipped, detach the 2 block heater wiring clips from the radiator support.

3. Detach the wiring harness retainers and position the harness aside.
4. Position aside the upper radiator hose from the cooling fan motor and shroud.
5. Disconnect the cooling fan motor electrical connector.
6. If equipped, remove the bolt and position aside the oil cooler bracket.
To install, tighten to 6 Nm (53 lb-in).
7. Remove the 2 bolts and the cooling fan motor and shroud.
To install, tighten to 6 Nm (53 lb-in).
8. To install, reverse the removal procedure.

[Neff22]

Hey thanks for all the help. I replaced my cooling fan assy and now the fans work. However they are constantly running. Even while the car is off. How can I fix this?

[WWWPerfA_ZN0W]

The 2007 FSM points to this as cause:

• A/C pressure switch (ACPSW) or ACP transducer sensor circuits

Part #11 in this illustration:

 

6F9Z19D594AA

 

autom8r has previously mentioned that a bad CHT (cylinder head temperature 9L8Z6G004C) sensor can do this also. Get the codes from the OBD II system to see if they are of any help in this issue.

 

In case there are followon AC issues:

http://www.fordedgeforum.com/topic/12884-08-edge-ac/?do=findComment&comment=100146

Edited October 9, 2015 by WWWPerfA_ZN0W

[Neff22]

How difficult is this to replace? Does not seem too bad!

[enigma-2]

Hey thanks for all the help. I replaced my cooling fan assy and now the fans work. However they are constantly running. Even while the car is off. How can I fix this?

Note what I wrote about some connectors being wired differently causing the fans to run continously, even when off. Need to reverse wires.