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Mario
Mario, ASE Certified Technician
Category: Ford
Satisfied Customers: 136
Experience:  Retired Automotive instructor with over 45 years experience as a technician, service manager and teacher.
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Ford fusion: I have a 2010 ford fusion hybrid driving me crazy...a/c

Customer Question

I have a 2010 ford fusion hybrid driving me crazy...a/c blower motor not working
Submitted: 1 year ago.
Category: Ford
Customer: replied 1 year ago.
forgot to mention it has automatic climate control.
Expert:  Mario replied 1 year ago.
Hi, this is Mario and I will be happy to help you today.Assuming you checked the fuses, I would start diagnosing at the relay. You should have power at pins 86 and 30 with the key on. If there is no power at these pins, there is an open between the fuse and the relay.If the voltage is OK, try removing the relay and put a jumper wire between the terminals for pins 30 and 87. If the blower now runs, the problem is in the control side of the circuit, the HVAC control panel or the relay itself.If the blower still doesn't run when you jumper terminals 30 and 87, the problem is either a defective blower motor or blower speed control module. Many times, these modules will burn out if the blower motor itself is drawing too much current.I am attaching a wiring diagram to help you out.I hope my information is helpful. Please let me know if you have any questions.Mario
Customer: replied 1 year ago.
I have checked all that, like I stated I have power to pigtail that plugs into motor..I have replaced motor and blower speed control module. I have 13 volts to motor pigtail, that varies as I change speed setting on display.
Expert:  Mario replied 1 year ago.
If you have hooked a separate ground wire and it still doesn't work, it's probably not a ground issue.You might have a defective NEW motor. Have you tried measuring the current draw of the motor?
Customer: replied 1 year ago.
I thought about that, I have purchased two new motors, neither worked. I hooked them straight to a car battery and they work.....I also bypassed the blower speed relay and hooked motor up to power that comes to blower speed relay,( 13 volts), motor will still not come on....if im thinking correctly, that should have took the Hvac control panel out of the loop.
Customer: replied 1 year ago.
Since I have 13 volts at pigtail that plugs into motor, and it varies when I change speed on control panel, I was thinking everything upstream of motor is good........but still no blower ....if blower works hooked straight to battery it should work hooked to 13 volts at pigtail.....I thought that system may be controlled by ground and hooking it to chassis ground may not exactly be the same as system ground....
Expert:  Mario replied 1 year ago.
The blower module (resistor) supplies both power and ground for the motor. The module is grounded through the Black/Gray wire at pin A. Have you tried jumpering pin A to ground? If it works, then the ground circuit is bad..
Customer: replied 1 year ago.
yes, I jumped pin A to ground, still not working......
Expert:  Mario replied 1 year ago.
Have you tried measuring the voltage drop across the motor when it is plugged in and won't run?
Customer: replied 1 year ago.
have not tried that yet, what numbers should I look for....I don't know normal current and resistance for a good motor.
Expert:  Mario replied 1 year ago.
You should see a 11 to 12 volt drop across the motor with it set to high speed. If it is less, you probably have high resistance in the circuit. This is typically caused by a corroded connection somewhere in the circuit.
Expert:  Mario replied 1 year ago.
I will be away from my computer for awhile. I'll check on you when I return later this afternoon.
Customer: replied 1 year ago.
ok, I wont be able check voltage drop till this evening anyway
Customer: replied 1 year ago.
I measured voltage drop across motor....it went to 0.0.....
Expert:  Mario replied 1 year ago.
That means the voltage is dropping somewhere else. Either on the ground side or the power side. The next thing you should do is a voltage drop of the power side of the circuit and of the ground side. This should tell you which side of the circuit has high resistance.
Customer: replied 1 year ago.
not sure how to do that to entire circuit....suggestions on where to attach meter?
Expert:  Mario replied 1 year ago.
Start by placing the red lead on pin A of the blower motor and the black lead to chassis ground. Try to run the motor and read the voltage. It should be close to zero. If you read voltage, there is resistance in the ground side. If you get a reading, move the red lead to pin A at the resistor and keep the black lead on chassis ground Try the motor again. If you now get zero volts, the problem is a bad resistor module. If you still get a voltage reading, the problem is a bad ground circuit between the module and chassis ground.If everything tests OK, you'll have to run the same tests on th positive side of the circuit. Remember, high voltage drop means you have high resistance in the circuit.
Customer: replied 1 year ago.
Sounds simple enough, daughter driving car today and tonight, wont be able to check till Thursday. Thanks
Customer: replied 1 year ago.
Test indicated bad control module.module is brand new....so I bypassed module... I plugged power going into module straight into motor ....still nothing....no voltage drop across motor but now no voltage drop from motor ground to chasis ground....
Customer: replied 1 year ago.
14 volts across motor pitail before I plug it in...then zero
Expert:  Mario replied 1 year ago.
If the 12 volts across the motor is going to zero, the voltage has to be dropping somewhere. You have tried measuring the voltage drop on the ground side. (Red lead on motor ground wire (gray) and black lead on battery negative). Have you measured it on the positive side? (Red lead on battery positive and black lead on motor positive (Yellow/blue)
Expert:  Mario replied 1 year ago.
Hi, this is Mario
was my information helpful? If it was, I would appreciate a positive rating as this is the only way I am compensated for my time and expertise. Thank you.
Customer: replied 1 year ago.
had problems viewing out converstation, had to go back to one of our first emails to get access. now all reading are good, except across motor is still zero.....motor does still work when hooked to 12 volt car battery....currently ordering another new control module just in case....This things still is not making electrical sense.....
Expert:  Mario replied 1 year ago.
When you say all readings are good, do you mean that you have zero volts dropped across the positive side and zero volts drop across the negative side with the motor connected?
See my answer above. If the 12 volts across the motor is going to zero, the voltage HAS to be dropping somewhere. Try measuring the voltage drop on the ground side. (Red lead on motor ground wire (gray) and black lead on battery negative). Then, measure it on the positive side. (Red lead on battery positive and black lead on motor positive (Yellow/blue). If you are reading zero across the motor, you HAVE to have a voltage drop on either the positive or negative side during this test. Wherever the voltage drop is, that's where the high resistance problem is.
Customer: replied 1 year ago.
I will perform test again, but last time I did them the only reading that showed problem was across motor......
Customer: replied 1 year ago.
All your reading request are less than 1 volt......I still have zero across motor....think I'll just take it to someone...thanks