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Brian
Brian, Ford Shop Foreman
Category: Ford
Satisfied Customers: 1361
Experience:  Ford Senior Master certified Tech, 36 years Ford technician.
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Ford Explorer: 2003 ford explorer , On ac and heat no air

This answer was rated:

2003 ford explorer , On ac and heat no air from the roof vents, checked the blower motor relays in the power distribution even switched 33 and 34 and still no air from the roof vents . I have been told no power going to rear blower motor. I do not have a test light yet to confirm that. Rear blend motor problem? On the 2003 are the rear blend door motors on the passenger or driver side? Best guess why no power to the rear fan. Front AC and heat as well as lower vents at the back of the front console all work great.

Brian :

The most likely cause is the rear air flow actuator. There is one fan in the rear, when the heat is selected, the air is directed to the floor vents because the heat will rise, when the ac is selected, it is directed to the roof so the cold air will drop, so if the heat is working, the fan is working, it sounds like the air flow is not changing. The rear unit is located behind the left rear trim panel.

Brian :

You will need to remove this panel in the left rear to check any of the actuators or the blower motor, you will need to get a test light or a volt meter to diagnose this system, start with the blower motor and see if you have power and ground at the rear blower motor connector with the system turned to full or high speed fan in the rear. If you have power and ground, the blower motor is bad.

Customer:

Brian:

Brian :

Yes, I am here.

Customer:

No mater what the rear controls are set to no air out the top vents, I can only find top vents and the vents coming out the back of the console. I had a part time mechanic check the fan and rear parts and he said now power to those components. I check the power distribution box and are really confused as I can find floor vents for the rear.

Customer:

meant I cant find floor vents in the back...

Customer:

meant no power to the rear parts

Customer:

by actuator do you mean rear blend motor controls?

Customer:

I do have a volt meter and can test that way.

Brian :

The rear duct is part of the left rear interior trim panel. and there are two actuators in the rear, one for the temperature control and one for the air flow control.

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Brian :

#12 is the air flow door and #14 is the temp control door.

Brian :

Test for 12 volts at the rear blower connector the rear blower on high speed setting,

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Customer:

Brian: Left is the driver side where the fan is?

Brian :

Yes, drivers side is the left side.

Customer:

this is my daughters car and I am trying to help her and not really familiar with the car. I found the vent for the heat in the rear and nothing comes out of it on heat either so either the fan is bad or some part of it or its not getting power from the power distribution box. In the manual it has relays/fuse for the fan and aux fan and another relay labeled fan. guess i will have to replace the relay labeled fan if the fan is not bad.

Customer:

I saw an internet posting indicating the fans usually not bad, a resistor on the fan yet on high the resistor is bypassed. Your thoughts?

Brian :

A fan motor is not common but I have seen them go bad, usually when the resistor goes bad, you will have high fan only, usually but not always, it can also fail completely and cause no blower at all, a relay is also not a common fault but they do fail, I would check the voltage at the blower fan connector first, if it has 12volts across the connector, the fan is bad. If it doesn't, see if there is power or ground. Testing across the connector will prove out power and ground to the motor, if you don't have both, see if you have one or the other, the orange/red wire should be ground and the pink/white wire should be power.

Customer:

OK. I have a pretty good idea now, Thank you so much, I will accept it.

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