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Ask Chad Farhat Your Own Question
Chad Farhat
Chad Farhat, ASE Certified Technician A6 - Electrical / Electronic systems A7 Heating / Air conditioning systems
Category: Ford
Satisfied Customers: 1573
Experience:  Owner at Carolina Auto Service & Sales , 20 years experience in Foreign & Domestic Vehicles
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We have a 2008 Expedition EL with a 5.4 liter V-8 engine,

Customer Question

We have a 2008 Expedition EL with a 5.4 liter V-8 engine, lately when we turn on the climate control unit the units fan motor speed control will not work, it blows at higher speed than the display shows it should be. When we turn the control off of auto the blower speed increases. The only solution so far we have found is to stop the car and turn the car off when we restart it the climate control is off and nothing is happening. What is the issue
JA: How many miles are on the car? Is it an automatic or a manual transmission?
Customer: Around 185000 miles and it is automatic with 4x4
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: If i can I would like to. I have not tried anything yet I am trying to educate myself before I make this a bigger problem
JA: Anything else you think the mechanic should know?
Customer: No other issues with the climate control until now
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Ford Mechanic about your situation and then connect you two.
Submitted: 6 months ago.
Category: Ford
Expert:  Chad Farhat replied 6 months ago.

Hi , my name is ***** ***** I will be assisting you today

Customer: replied 6 months ago.
ok so what is the fix to my issue
Expert:  Chad Farhat replied 6 months ago.

The A/C compressor clutch will only be engaged by the PCM if all of the following conditions are met: - The HVAC module is set to a mode which provides an A/C request to the PCM. - The evaporator discharge air temperature sensor is reading a temperature above 3°C (37°F). - The A/C pressure transducer is not reading an excessively high or excessively low pressure in the refrigerant system. - The A/C compressor relay is switched to the CLOSED position by the PCM. - The engine coolant temperature is not excessively high. - The PCM has not detected a wide open throttle (WOT) condition.

we need to check on few things first

, but the most common causes will be blower resistor or the a/c control head unit in dash

i sent you a location of the blower resistor

Expert:  Chad Farhat replied 6 months ago.

does yours have a dual climate control , like you can set tempos for either side , driver & passenger ?

Expert:  Chad Farhat replied 6 months ago.

this is the a/c control unit

Expert:  Chad Farhat replied 6 months ago.

This unit is more likely the problem since when you turning the igntion off and back on it is resetting

with the mileage on it you have and from what you describing the head control unit, controls all the a/c operation and ventilation control , defrost, floor ,etc ..

of course testing is needed , I m not sure you trying fix yourself or you want to take it to somebody to repair ?

Expert:  Chad Farhat replied 6 months ago.

I usually pull the control unit out of the dash and double check before replacing part that the issue is not the connector going into it , in case it got hot and ,melted and it is shorting out intermittently .

A positive rating is much apreciated

This post will stay open for you to come back and ask me any follow up questions you may have .

I have all the wiring diagrams,component location , part # ***** ... for this vehicle in case you decided to troubleshoot yourself

Thank You ***** ( aka -Customer)

ASE Certified Tech

Expert:  Chad Farhat replied 6 months ago.

I sent you the part # ***** these units

Vehicle » Heating and Air Conditioning » Control Assembly » Parts and Labor

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2008 Ford Truck Expedition 4WD V8-5.4L

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Parts InformationOEM Part #Price

Control Assembly

Main Controls

Dash Control Unit

Without ATC

With Auxiliary AC

From 12/6/06

Without Floor Console

AL1Z19980H$183.07

With Floor Console

AL1Z19980F$377.73

With ATC

Without Temp Control Seats

To 8/30/11

AL1Z19980E $426.77

With Temp Control Seats

To 8/2/11

AL1Z19980G $544.27

Auxiliary Controls

Heater & AC Control

8L1Z19980D $429.58

just an idea for you , if you dont want to mess with wiring and testing and the control unit is fairly easy to change ,just couple screws , you can order one replace it and see if it worked if not return part and take it to dealer and let them run a scan of the a/c system .