73 Fan motor with a/c

[Gardoco]

My heater blower motor is occasionally noisy on speeds 2 & 3.

Is it possible to remove & replace the fan motor (a/c car) without major dismantling of dashboard?.

The fan& mounting plate appears to be held in with 4 screws

The fan motor is visible in the footwell up above to the right of the accelerator pedal and slightly shielded by some hvac ducting.

Does this ducting unclip to allow better access.

Has anyone done this?

All suggestions & advice welcome

 

[72HCODE]

yes removing the fan is very possible it is tight but can be done.

electrically there is one ground connected with a bolt that you can reach with a ratchet extension.

the power is provided with a connector down by the accelerator pedal.

you then have 4 bolts to remove that you have seen and then the fan will come out, a little maneuvering and out it comes to the foot well.

there shouldn't be ducting in the way that i remember, maybe the floor vent the floor vent has one or 2 screws and a pop clip in the center if you loosen it it should move around and give you enough room. To pull out the floor vent is a big pain if you have a floor console that needs to come out and if i remember i needed to loosen the center panel to try and get clearance to pop the clip. the problem is you can break the clip off the floor vent if your not VERY careful.. I think i have a photo somewhere but not sure.

I've taken mine out 2 times but it was years ago now.

I swapped my original for a repop fan duct motor. The problem was the repop fan motor, caused radio interference with the OEM am/fm radio, i then got another OEM Fan and cleaned that up and installed that in place of the reproduction fan motor.

 

[Gardoco]

72HCODE, thanks for the info, it's good to know its possible.

The duct I mentioned fits your description of a floor vent.

I have a re pop motor from NPD, your comment on possible radio interference is a little disconcerting.

I can obviously hook the new motor up to the battery to test it with the radio on but I wonder if that would show up any such interference?

Do you think you maybe just had bad luck with that particular fan motor?

 

[72HCODE]

I think it was the proximity of the fan to the back of the radio.

If you have an aftermarket radio you might be ok.

I never took a chance and bought another reproduction fan motor so no idea if i was just being unlucky. The radio interference was pretty bad to the point I couldn't listen to the radio when the fan was running. Then when I swapped the repro for a second original fan. The noise went away.

I do know there is a trade off because the amp load on the fan switch is much higher with the old fan, causing the ground wire inside the connector that goes on the back of the fan switch to get super hot and melt the plastic. I just had to modify that connector with a new ground tab but the heat is still very high on the electrical connection.

 

[BrandonDindorf]

Did you try using interference blockers or possibly isolating the circuit? I would assume that if one side of the wire is melting the other could be warm as well. Ever think about re soldiering larger power and ground wires and just color match them? That in theory would be easy and that's a pretty big hazard.

 

[72HCODE]

well having to start playing around with installing noise capacitors on a non-serviceable electric motor made in china, verse just swapping it for a better condition OEM unit and having the problem go away was where i basically stopped messing with it. i figured something was up with the replacement motor and i wasn't going to keep spending money in an effort to re-engineer the electrical.

I did clip the wires and i installed gold connector tabs which i silver soldered to the original harness wires. they still get hot at the switch. i wasn't going to start soldering the rivets on the switch so i just made a call it was the best it was going to be at this point. going further started to become a maintenance hassle as well. plus every A/C car i have seen has that connector melted from heat.

but that is nothing want to see how the fan speed actually works?

on the side of the fan box is a 2 bolt red piece of plastic with connector tabs on it. the switch wiring goes to there.

it is an Open air resistor wire that basically gets red hot when in use, but the fan spinning keeps it from going nuclear and melting through the housing and setting fire to the carpet LOL!





awesome right, ford engineering lol

 

[BrandonDindorf]

Is this the same for non AC cars? I am actually doing something different on with my restoration, I had an AC car; I ripped out all the original air assembly got a non air cowl and entire heating assembly if this is the same issue I'm going to completely re wire it. This is unacceptable. I'll figure what the resistance levels and post what they are for a safer alternative.

 

[72HCODE]

yup the heater core only cars use the same wiring, switch and blower fan. the load is suppose to be 5-7 amps at 12.8volts setting to full power. i think the problem really is with the high ohms of the switch itself.

the heat is always highest at the connector. the crimps on the wire harness are always corroded and the wires actually have rust on them.

the connector always tends to vibrate off the switch that makes the resistance go up and the first sign of a problem is the fan turns on and then after a couple of minutes it shuts itself off. if you turn it off for a couple of minutes and then turn it on again it will come on for a few seconds again. this is because the connector has heated up and the resistance shoots to the moon with the extra heat on the connection. usually you pull the connector off the switch and plug it back in. I did this for a while then i got fed up with the ground connection being really hot and dirty with melted plastic. I clipped the tab soldered a new section of wire then soldered a new connector put the whole thing back together and its still pretty hot after a while i'm sure most of it is the motor is 40 years old and i'm sure its worn a bit pulling more amps then it should but the fuse doesn't pop so i keep going with the A/C running its fine since the back of the dash gets cold air from the leaks in the system.

rewiring it would be a nice option if you can but you will find the original switch is where the problem is, i've swapped at least 4 or 5 switches in and they all have the same problem.

 

[Gardoco]

For A/C cars

Well my original heater fan motor was getting noisier so I decided to swap in the repo one I've had for a while.

I removed the radio and face plate allowing access to remove two button/spring clips holding the floor vent in place.

There is one more of these spring clips at the rear of the vent on the drivers side that is easy to remove via the footwell.

With these clips removed the floor vent can be wriggled out via the drivers footwell.

Remove the vac pipe from the canister near the accelarator pedal.

Remove the two nuts holding the acclerator pedal linkage to the firewall and swing out of the way (no need to disconnect cable)

Now remove four 5/16" screws holding fan motor to housing and unplug +ve wire and unscrew 1/4" -ve wire ring connector.

Remove motor and squirrel cage from housing.

Use 1/8" Allen key to remove Cage from motor, note: when replacing cage to new motor allow some tolerance otherwise the cage can rub on the motor shroud.

I used a piece of thin card to 'space' the cage away from the shroud before tightening the allen screw (I used loctite to be sure)

I cut the wires from the original motor along with connectors and spliced them into the new motor wires using solder and shrink-wrap.

The extra length of these wires allowed easier connecting after the new motor was installed.

All seems good and I've not experienced any 'Radio electrical interference' so far.

 

[dzstang71]

For A/C cars

Well my original heater fan motor was getting noisier so I decided to swap in the repo one I've had for a while.

I removed the radio and face plate allowing access to remove two button/spring clips holding the floor vent in place.

There is one more of these spring clips at the rear of the vent on the drivers side that is easy to remove via the footwell.

With these clips removed the floor vent can be wriggled out via the drivers footwell.

Remove the vac pipe from the canister near the accelarator pedal.

Remove the two nuts holding the acclerator pedal linkage to the firewall and swing out of the way (no need to disconnect cable)

Now remove four 5/16" screws holding fan motor to housing and unplug +ve wire and unscrew 1/4" -ve wire ring connector.

Remove motor and squirrel cage from housing.

Use 1/8" Allen key to remove Cage from motor, note: when replacing cage to new motor allow some tolerance otherwise the cage can rub on the motor shroud.

I used a piece of thin card to 'space' the cage away from the shroud before tightening the allen screw (I used loctite to be sure)

I cut the wires from the original motor along with connectors and spliced them into the new motor wires using solder and shrink-wrap.

The extra length of these wires allowed easier connecting after the new motor was installed.

All seems good and I've not experienced any 'Radio electrical interference' so far.

How are the button clips removed? I am afraid of doing it wrong and busting them.

 

[Gardoco]

Dzstang71, the clips are a fairly loose fit and popped out with little pressure, I don't recall if I used a tool or fingertips but it was easy to remove them.