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fan motor not working


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I am having issues with the fan motor. The AC and heat have worked well since I bought the car. The fan motor was quiet and worked on all 3 speeds. I checked the fuse and it was good and replaced it anyway with no results. I have the wiring diagram but am not sure where to start. Any help would be great.

 

John

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good chance its the ground on the plastic connector that goes behind the switch.

 

right behind the up and down switch face with lever that controls the fan speed is a brown wire harness connector.

 

you can reach behind the center panel of the dash by the accelerator pedal and get to it without taking the dash apart.

 

pop the connector off the switch and look at it, is the top black wire going into the brown plastic connector all melted.

there is enough slack on the wire to pop it out and pull it down by the accelerator pedal. the black wire will also be the thickest wire of the set.

 

that is the main ground for the entire system and it seems to carry a TON of amperage up to 20Amps on the fuse box.

so that wire gets SUPER HOT hence the melted plastic.

 

step #1 push the connector back onto the switch and test the fan. it usually comes back online because that brown connector vibrates loose over time and you have bad contacts.

 

great if it starts working, bad news is it will keep happening and that black wire gets hot enough to start a fire if you don't constantly remember to pop that connector on and of in an effort to self clean the connections.

 

step #2

 

on mine i had to cut the black wire out of the connector. the tab was Heavily corroded and filled with melted brown plastic from the connector.

 

I then Clipped the black wire and shaved the terminal off the brown connector. after 40 years my black connector was all full of carbon and rust and melted plastic and a bad crimp job from ford.

 

I crimped a new tab on the wire then Silver soldered the tab to the black wire everything is so very corroded so silver solder was the only thing that would stick even after i tried acid on the wire.

 

after i finished that i plugged the connector back into the switch on the bottom terminals. not easy but you can feel your way to get the connector back on the switch. then i connected the black wire manually with the tab to the top of the switch.

 

since the ground is now separate of the connector it holds better, it still gets hot but now there is an air gap around it.

 

I once attempted to change the fan motor with a REPOP to see if it would draw less amps. it drew the same amps then caused interference with the radio creating a WUB WUB WUB noise all the time and driving me insane i went back to the 40 year old oem fan.

 

so your issue is most likely that brown connector that plugs into the back of the fan switch behind the dash.

 

try step #1 pull it off and then plug it back in and it should fire up again but make a note you have a problem that could be a fire hazard if the resistance is high enough before the fuse blows.

 

with all the work i did on mine even with soldering the tab to the wire it still gets hot enough to be uncomfortable to touch.

and i did change my switch a couple of times same resistance problem driving the heat level up.

 

 

the easy way even with a floor console is get your hand behind the panel right behind the area of the switch and follow the wires forward to the connector when you feel it, just pull back on the connector and it will pop off the switch. i believe it is a 5 terminal connector, looks like a 'P'

once you pop it off you can pull it back to the foot well about 6" to look at it with a flash light and see how messed up it is. then you can try popping it back on and see if the fan starts working again. pulling it on and off sort of self cleans the tabs on the switch. but it will still be an issue.

 

when you pop it back on get your fingers just a little in front of the connector so you can feel the tabs on the back of the switch and that will help you guide it blindly back onto the switch.

 

you can turn the ignition counter clockwise to acc mode and run try running the fan without energizing the coil.

 

ACC-OFF-RUN-START is on the ignition. ACC is good for diagnostics and just running off the battery for power.

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good chance its the ground on the plastic connector that goes behind the switch.

 

right behind the up and down switch face with lever that controls the fan speed is a brown wire harness connector.

 

you can reach behind the center panel of the dash by the accelerator pedal and get to it without taking the dash apart.

 

pop the connector off the switch and look at it, is the top black wire going into the brown plastic connector all melted.

there is enough slack on the wire to pop it out and pull it down by the accelerator pedal. the black wire will also be the thickest wire of the set.

 

that is the main ground for the entire system and it seems to carry a TON of amperage up to 20Amps on the fuse box.

so that wire gets SUPER HOT hence the melted plastic.

 

step #1 push the connector back onto the switch and test the fan. it usually comes back online because that brown connector vibrates loose over time and you have bad contacts.

 

great if it starts working, bad news is it will keep happening and that black wire gets hot enough to start a fire if you don't constantly remember to pop that connector on and of in an effort to self clean the connections.

 

step #2

 

on mine i had to cut the black wire out of the connector. the tab was Heavily corroded and filled with melted brown plastic from the connector.

 

I then Clipped the black wire and shaved the terminal off the brown connector. after 40 years my black connector was all full of carbon and rust and melted plastic and a bad crimp job from ford.

 

I crimped a new tab on the wire then Silver soldered the tab to the black wire everything is so very corroded so silver solder was the only thing that would stick even after i tried acid on the wire.

 

after i finished that i plugged the connector back into the switch on the bottom terminals. not easy but you can feel your way to get the connector back on the switch. then i connected the black wire manually with the tab to the top of the switch.

 

since the ground is now separate of the connector it holds better, it still gets hot but now there is an air gap around it.

 

I once attempted to change the fan motor with a REPOP to see if it would draw less amps. it drew the same amps then caused interference with the radio creating a WUB WUB WUB noise all the time and driving me insane i went back to the 40 year old oem fan.

 

so your issue is most likely that brown connector that plugs into the back of the fan switch behind the dash.

 

try step #1 pull it off and then plug it back in and it should fire up again but make a note you have a problem that could be a fire hazard if the resistance is high enough before the fuse blows.

 

with all the work i did on mine even with soldering the tab to the wire it still gets hot enough to be uncomfortable to touch.

and i did change my switch a couple of times same resistance problem driving the heat level up.

 

 

the easy way even with a floor console is get your hand behind the panel right behind the area of the switch and follow the wires forward to the connector when you feel it, just pull back on the connector and it will pop off the switch. i believe it is a 5 terminal connector, looks like a 'P'

once you pop it off you can pull it back to the foot well about 6" to look at it with a flash light and see how messed up it is. then you can try popping it back on and see if the fan starts working again. pulling it on and off sort of self cleans the tabs on the switch. but it will still be an issue.

 

when you pop it back on get your fingers just a little in front of the connector so you can feel the tabs on the back of the switch and that will help you guide it blindly back onto the switch.

 

you can turn the ignition counter clockwise to acc mode and run try running the fan without energizing the coil.

 

ACC-OFF-RUN-START is on the ignition. ACC is good for diagnostics and just running off the battery for power.

 

Learn so much just reading the advise you give to others. Think that badge should read super duper tech advisor!!!

28iw51u.png

"I prayed to God he would change Johnny but his plan was to change me"

 

Gene Stallings

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you know how you learn?

 

buy the worst car in existence with everything wrong with it, trial by fire. i had to replace everything that bolts to the body of my car so i remember where everything goes.

Its really funny when a friend comes over that sat in the car 10 years ago and i remind them its actually not the same car, just looks the same.

 

Its like that old adage: you buy an AXE. one day your chopping with it and you break the handle. so you replace the handle. 2 years later you crack the blade and buy a new blade. is it the same axe now?

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Open the drivers door. Put a towel on the ground. Lean on your knees up against the rocker.

Dip your head under the steering wheel and with your left hand start by the accelerator pedal and wrap around the back of the center instrament panel. Aim for the back side of the switch. You will feel the wires going into the switch and then the hard plastic connector. Close your eyes it will help too. The first time it's confusing but you will be able to either grab the connector or you can wiggle it and see if it is loose and push it back on and try the fan.

 

If that still doesn't work you can pop the fuse out of the fuse box, with replace it or pop it back in and see if it was a bad contact there. If that fails there is another connector on the side of the fan box on the red piece of plastic you can pop those 2 connectors on and off and try again.

 

Baring that there is a screw in ground up behind the dash you can get to if you pull the drivers seat out. And after that you have to start backtracking a broken wire with a ohm meter.

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  • 2 weeks later...

Pulled the wire harness and reconnected it. No luck. The wire connector is in great shape no sign of corrosion. I am going to look at the fan connections next. I have the Ford 1973 service highlights manual for heating, ventilating and conditioning system changes. There are some good trouble shooting tips in it. I just need to take the time to read it.

 

Thanks

 

John

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  • 2 months later...

The weather changing and needed some heat in the car. Ran a jumper from the fuse block the fan motor and it works fine. They ran a jumper from fuse block to the switch and it works fine and the fan runs on all 3 speeds. pull the fuse block out and inspected it and found no hot spots or broken wires. fuse is good and there power on both sides of the fuse. The problem is between the fuse block and the switch

 

If anyone has any ideas please let me know. This is on 1973 vert

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If your fan motor is working ... the rest is relatively cheap to fix...

from memory, I even pulled my fan to bit and serviced it to stop any noises...

 

It should be as simple as following the wires now from the fan to the fuse box...

Is it possible that it was joined at one stage with tape!?

 

There is electrical schematic for all our models here somewhere, just take your time and follow the wires...

"Midlife" has them somewhere also...

 

There's no computers in our cars, just simple wires and at worst a relay.

 

A cheap multimeter is your best friend...

Image3.png

Jim

 

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We got it fixed finally. I not excally sure what the porblem was but it working fine now. I work for a school district and I had one of the auto shop teachers help me out. We ended up pulling the fuse block out of the wiring harness so we could inspect it. We cleaned up the fuse clips and pintched them so they would be a little tighter holding the fuse and the fan started working. I had one teacher taking the car apart and the other one on the phone telling me what to look for.

 

It was team work at its best and It did not cost me a dime. Which is very rare for my car.

 

John J

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Yup that happens :( I get it from time to time in my car also you get a little oxidation and things stop working. I have to sand the fuse connections every so often. Like sometimes my horn stops working sand the fuse block and its fine for a couple of months again. For the fan usually its my switch and I have to unplug and replug the connector and it works again.

 

Electricity is fun like that. You can have too pretty clean surfaces touch and they will not conduct, resand the connecton and poof works.

 

 

We got it fixed finally. I not excally sure what the porblem was but it working fine now. I work for a school district and I had one of the auto shop teachers help me out. We ended up pulling the fuse block out of the wiring harness so we could inspect it. We cleaned up the fuse clips and pintched them so they would be a little tighter holding the fuse and the fan started working. I had one teacher taking the car apart and the other one on the phone telling me what to look for.

 

It was team work at its best and It did not cost me a dime. Which is very rare for my car.

 

John J

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Electrical gremlins are enough to send you bonkers ( and my specialty is electronics!)

I had too many crappy joined wires from god knows how many PO's, so I cracked the poos and rewired the whole car!

Sometimes breaking walnuts with a sledge hammer is justified...

 

Enjoy the warm air now that winter is approaching for you guys....

Image3.png

Jim

 

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  • 2 years later...

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