No Blower Fan

Tiny
JNP_MACKLIN
  • MEMBER
  • 1999 MERCURY MYSTIQUE
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 90,000 MILES
OK. This one has me baffled.

Sister in Law asked me to look at her car for no blower motor concern. According to her, the blower stopped working on all slower speeds except full-on earlier this year, but she didnt have the $$ to have it repaired. The current problem has escalated so that the fan no longer works at all.

I have checked the following.

Power Distribution Box Fuses: All good (Checked with multimeter)
Interior Fuse Panel: All Good (Checked with multimeter)
Relay for Heater: Good (swapped positions with another working relay)
Fan Motor: Works when directly connected to 12v source (Removed and used jumper wires to battery)
Fan Switch: Replaced (See Below)

I have confirmed that 12v power is at the wiring harness that plugs into the fan control switch. Upon my initial removal of the fan switch from the wiring, I noticed that it looked like there may have been a considerable amount of electrical arcing causing the plastic plug to melt and become slightly deformed and the contacts to show corrosion. I have shot terminal cleaner in the harness, and cleaned up the plug as best I could. The plug shows no melt-through where the contact points would be touching inside the harness plug. The melting heat was also evident on the switch assembly itself, prompting me to go ahead and replace the fan switch. No difference in symptom.

I have checked with FoMoCo, by VIN, becasue I did locate info about a recall with 1996, and some 1999 Mystique's citing a "faulty resistor" as the cause of the problem I described, including the melting of the harness, resulting in an "open circuit" condition. According to FoMoCo, this vehicle has no recalls on it.

I have exhausted my diagnostic knowledge, and am looking for suggestions. If my Sister in Law decides not to spend the $$ to have a Ford technician examine it, the next step would be to run wires for a seperate switch and relay to turn the fan, on and off manually. I'd hate to butcher up the wiring, if I dont have to.

Thanks for your help!
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Saturday, December 8th, 2007 AT 7:11 PM

22 Replies

Tiny
RASMATAZ
  • MEMBER
Try testing the blower motor relay at under left side of dash on the central junction box and also the blower motor resistor right side of dash, near the blower motor.
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Sunday, December 9th, 2007 AT 5:15 AM
Tiny
JNP_MACKLIN
  • MEMBER
I have tested the blower motor and it works. The resistor, I replaced with OEM from Ford. No difference.

The last switch I havent confirmed operational is the plenum/ducting/AC control in the center of the console that lists heat, panel, floor, def, etc.

I did jump across the 4-wire control harness and was able to confirm the fan turned on, and I also was able to control the fan speed with the switch using the jumper. Upon the test, after about 30 seconds, I blew a 15 amp fuse for the back-up lights and the motor stopped working. (Why the "back up lights" fuse blew when I was testing the climate controls, I'll never know)

Thanks again for your assistance.
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+1
Monday, December 10th, 2007 AT 11:45 AM
Tiny
RASMATAZ
  • MEMBER
Try the blower motor relay see below, also the circuitry.
Here's a guide on testing wiring

https://www.2carpros.com/articles/how-to-check-wiring

Wiring diagrams are attached below
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-1
Monday, December 10th, 2007 AT 12:32 PM
Tiny
BABBITTN2004
  • MEMBER
  • 1999 MERCURY MYSTIQUE
  • 2.0L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 86,000 MILES
I've taken out the blower motor--it was rather simple, and upon turning the fan on, it works on all speeds. Fuses and relays all tested fine. But when the motor is secured in the housing, the fan does not work. I looked at the inside of the blend door actuator and found no broken gears. The actuator when not in place does rotate, but it only moves to one position and stops. I'm out of ideas, and I am not proficient in electrical on cars. Is there something else I need to test electrically to see if something is wrong, or is there a mechanical part that could potentially need to be replaced? Winter is drawing near, and I am going to need defrosters for sure to work.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
JDL
  • EXPERT
Sometimes if you jiggle a blower motor it may run? The vibrations may cause the brushes to make contact, intermittently. With blower motor installed, check for voltage and ground, controls turned on, violet wire is voltage, black wire is ground.

Your directional actuator doors appear to be vacuum controlled. Most vehicles I work on, if vacuum is lost, it defaults to defrost.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
JDL
  • EXPERT
Welcome to the forum, check fuses, fuse 37--30amp, not only check fuse, use a testlite and check fuse circuit, should be hot all the time. Also, check fuse 25--15 amp, fuse circuit goes hot when you turn on the key. These fuses should be in the underhood fuse box. They supply voltage to blower motor relay. I haven't checked the turn circuit, yet. Parts of both circuits are ignition feed. I'm not saying the ignition switch is faulty, I'd have to check the circuit feeds.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
JRFIGHTER
  • MEMBER
[quote:895be4b882="mastiflaw67"]Heater problem
1998 Mercury Mystique 6 cyl Front Wheel Drive Automatic 110000 miles

most likely a fuse its a 30 amp fuse far right bottum row hope it works for u
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
SAMMYCOLORS
  • MEMBER
  • 1998 MERCURY MYSTIQUE
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 86,000 MILES
My battery in my car went dead due to me leaving my lights on. When we jumped it off the battery built back up but now my fan for my heating and air will not work. I don't know if what happened had anything to do with it or not. Can you give me any suggestions, and how do I check for 12 volts that I have read about.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
See below


http://www.2carpros.com/forum/automotive_pictures/12900_blower1_3.jpg




http://www.2carpros.com/forum/automotive_pictures/12900_blower2_3.jpg




http://www.2carpros.com/forum/automotive_pictures/12900_blower3_2.jpg

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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
AMANDARALLEN83
  • MEMBER
  • 1999 MERCURY MYSTIQUE
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 17,600 MILES
How do I take off the blower motor under the dash? I can not find the screws to take it off.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
SATURNTECH9
  • EXPERT


http://www.2carpros.com/forum/automotive_pictures/416332_1999_mercury_mystic_blower_motor_removal_1.jpg


There's the info you need.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
PENQUIN1
  • MEMBER
  • 1996 MERCURY MYSTIQUE
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 146,000 MILES
My blower motor fan quit working on all levels of speeds and when I changed the fuse it blew again in about 30 seconds, this happened twice. So I had new blower motor fan installed and it did the same thing, it blew the fuse again in about 30 seconds or less, why? This is the first time asking question here and I will gladly donate money the next time but I want to see how good these gentlemen are first with my first time question and being a new member. Thank you
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
BLACKOP555
  • EXPERT
Since the motor has been replaced I would suspect a faulty wiring harness, I would be checking the wires for resistance or voltage drop at the from fuse to switch, and from switch to motor.

Put the fan speed on high and turn the key on with new fuse, does it blow the fuse again? If not you may have a bad blower motor resistor block.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
EDRUM
  • MEMBER
  • 1998 MERCURY MYSTIQUE
  • 6 CYL
  • FWD
  • MANUAL
  • 100,000 MILES
One minute my blower fan was working, the next it quit. No airflow at all. Fuse is good so is relay. What is likely the problem
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
At the blower motor connector power the violet and orange wire from the battery positive post and put blower switch to any position-Did the blower motor turn On?
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
EDRUM
  • MEMBER
Yes I found a broken wire going to the battery. Thanks
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
JENIFEREVERS
  • MEMBER
  • 1995 MERCURY MYSTIQUE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 150,000 MILES
The heater/air conditioner stopped working on the highest blower setting about a year ago. Recently, the next highest setting went out, leaving me with the two lowest blower settings in a very cold climate. I have been told it could be the resistor or the switch. Can you send me a manual? If not, can you tell me how to determine which part needs to be replaced? Thanks!
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
BRYANT.ROBBINS
  • MEMBER
The switch you need is about twenty dollars. If your blower motor is still working, I'm betting it is your switch. I had the same problem. Take it out and take it apart. You'll be able to tell if the switch is bad because the metal will be burned.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
COURTRIGHT
  • MEMBER
  • 1995 MERCURY MYSTIQUEMERCURY MYSTIQUE
I have a 2000 Mercury Mystique. The heater works as does the A/C. One day I turned the heater down from high to low and it didn't work. Right now the heater only blows heat when placed on high. The fuses seem to be fine. Not sure what to do. Please let me know what you think. Thanks

TC
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Monday, October 29th, 2018 AT 6:20 PM (Merged)
Tiny
TGULCH
  • MEMBER
Check the resistor. Blower resistor to be exact. It limits the voltage to the blower motor as you cycle through the speeds. If it only works on high them the other speeds might be blown.
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Monday, October 29th, 2018 AT 6:20 PM (Merged)

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