A/C Blower Motor

Joined
Apr 16, 2017
Messages
330
Location
Georgia, USA
Vehicle is a 1992 Ford Explorer, Eddie 'edward' Bauer 4WD, 4 liter V6

Air conditioner pumps cold air; however, the blower does not seem to have a 'high' speed anymore, even on Max Cool. I have three of four speeds, not counting 'off': low, medium-low, medium-high, and what used to be the 'blow you out the window' high remains on medium high.

Fuses are good. If I understand correctly, a faulty resistor would lock the fan speed on high only. That's not the case. What am I missing?


Thanx in advance.
 
Isn't there a blower motor high speed resister in there? I'm pretty sure if the resister goes out the fan will still blow on the lower speeds.
 
Originally Posted by oldhp
Isn't there a blower motor high speed resister in there? I'm pretty sure if the resister goes out the fan will still blow on the lower speeds.


Thanks, I'll have to check out (as in find) the resistor module. I've been told the fan will only blow on high, or as you stated, on the lower speeds - from two different parts stores (Yeah, I know, consider the sources). If my guess is right, on mine the resistor would be on the side of the housing for the evaporator. ( ?? )
 
Originally Posted by maxdustington
Edward Bauer edition LOL!



For what it cost way back then when new . . . yeah, we called it 'Sir Edward' until it was paid off.
 
My 89 Dodge at one point had 3 of 4 of the lower speeds, but turbo was not available, it would just stop spinning.

This vehicle runs full blower motor current through the speed switch itself.

i found the contacts for 'highest speed' were burnt and occluded with carbon and the wiring insulation leading to the speed switch were burnt near the connectors.

I Still have the same switch, just cleand and polished the contacts, added a bit more spring pressure, and upgraded the wire size leading from fuse block to the switch and from switch to the resistor and blower motor. Now highest speed has even more 'turbo' as significantly higher voltage is now reaching the blower motor. It also used to blow 30 amp fuses regularly before this modification, now the 20 amp fuse never blows.
 
Check the resistor first. Debris can accumulate in the evaporator box and cause issues. Losing some speeds but working on others is typically the resistor, but pull the blower motor too and clean everything out. I found burned leaves in mine. There were grommets to seal around the wiper arms and keep junk out, but not sure if they are still available.
 
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My 89 Dodge at one point had 3 of 4 of the lower speeds, but turbo was not available, it would just stop spinning.

This vehicle runs full blower motor current through the speed switch itself.

i found the contacts for 'highest speed' were burnt and occluded with carbon and the wiring insulation leading to the speed switch were burnt near the connectors.

I Still have the same switch, just cleand and polished the contacts, added a bit more spring pressure, and upgraded the wire size leading from fuse block to the switch and from switch to the resistor and blower motor. Now highest speed has even more 'turbo' as significantly higher voltage is now reaching the blower motor. It also used to blow 30 amp fuses regularly before this modification, now the 20 amp fuse never blows.
lt don't even use a relay?
 
Order up a Motorcraft YH1698 resistor pack
If the motor is getting old, and drawing too much current, it'll keep chewing through resistor packs
In that case, replace the blower motor with a Motorcraft MM751
 
Edward Bauer edition LOL!
That’s sweet that a car that age is still on the road!

I saw an elderly man driving a special edition 1980 Toyota Celica a few years ago. It had a honeycomb grille and I remember as a kid thinking that car was hot

 
While my upgraded circuit and speed switch never had another issue, I decided to try a sub 20$ 21khz 40 amp PWM motor speed controller controlling blower motor.

Loved the infinite speeds between min and max, and never hooked the original circuit back up, and then regretted having going through the effort and expense of rebuilding the original.
 
While my upgraded circuit and speed switch never had another issue, I decided to try a sub 20$ 21khz 40 amp PWM motor speed controller controlling blower motor.

Loved the infinite speeds between min and max, and never hooked the original circuit back up, and then regretted having going through the effort and expense of rebuilding the original.
I've thought about hooking a 12 V PWM board with a ~5K pot for Infinite speeds too!
 
While my upgraded circuit and speed switch never had another issue, I decided to try a sub 20$ 21khz 40 amp PWM motor speed controller controlling blower motor.

Loved the infinite speeds between min and max, and never hooked the original circuit back up, and then regretted having gone through the effort and expense of rebuilding the original.
But Factory didn't even use a relay?
 
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