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need help with controller

grumpyoldman

🧲 New user
Joined
Apr 10, 2026
Messages
4
Location
Oak Park CA
I need help with a brushless a/c blower motor controller. I am waaaaay out of my area of expertise on this. I need to use a brushless blower motor on the a/c in my car as a brushed motor won't push enough air. With much research I found an assembly that will (with modification) fit into my fan housing. I need a controller to operate the motor. I need one that will control the fan speed and most of all be reliable. Being in So. Cal. in the summer anytime the engine is running the A/C is on by necessity. A Google search reveals controllers of all size and voltage requirements but I feel like a blind man looking for that needle in the haystack.

Any help will be greatly appreciated
Dwight
 
I need help with a brushless a/c blower motor controller. I am waaaaay out of my area of expertise on this. I need to use a brushless blower motor on the a/c in my car as a brushed motor won't push enough air. With much research I found an assembly that will (with modification) fit into my fan housing. I need a controller to operate the motor. I need one that will control the fan speed and most of all be reliable. Being in So. Cal. in the summer anytime the engine is running the A/C is on by necessity. A Google search reveals controllers of all size and voltage requirements but I feel like a blind man looking for that needle in the haystack.

Any help will be greatly appreciated
Dwight
Make sure the controller is rated for sufficient current to meet the motor specs.
If the motor is sensorless, you will need either a sensorless or dual mode controller that support sensorless operation.
If the motor has hall sensors, then either a sensored or dual mode controller is needed.

I understand that being blind creates a greater challenge for providing additional details about your motor, but if you could get someone to help you add links or screenshots, it would support more targeted guidance. They can refer to the article below on how to add links, pics, and info:

 
The bods who build RC models have been using brushless motors for ages and have built up a vast and available knowledgebase and are more the sort of scale of an a/c blower rather than a vehicle drive wheel ;)

Try a few RC hobby forums perhaps posting pics as suggested above, Im sure the technical expertise exists here but the rc bods will certainly have more hands on experience with the sort and size of motor your a/c employs. - and they are generally a friendly and inclusive bunch

edit in fact im pretty sure a 'servo tester' is a thing you can 'plug into a motor and power and run it with a knob control?
shopping
 
I need help with a brushless a/c blower motor controller. I am waaaaay out of my area of expertise on this.
What are the specs on the motor? They should be stamped on it somewhere. Were talking about a speed controller of course and you currently have a variable speed A/C dial? A 3 or 4 level rotating switch? That will have to be dealt with too of course.

BTW, modern cars have a filter before the fan, have you checked that to make sure it isn't clogged? I remember a dust storm crossed my city a decade and a half back and everyone just drove around through it as normal. Later there were massive issues with car climate control and engine performances.
 
What are the specs on the motor? They should be stamped on it somewhere. Were talking about a speed controller of course and you currently have a variable speed A/C dial? A 3 or 4 level rotating switch? That will have to be dealt with too of course.

BTW, modern cars have a filter before the fan, have you checked that to make sure it isn't clogged? I remember a dust storm crossed my city a decade and a half back and everyone just drove around through it as normal. Later there were massive issues with car climate control and engine performances.
It is not a modern car. It is my daily driver, a 1963 Pontiac convertible. As was common for GM cars of the era convertibles generally came without A/C. When I was building the car I adapted a unit off of a 97 Crown vic. I was never able to get the temperature stabalized it was sort of on again off again. I finally repaced the drive train with an engine/ trans out of a 15 Silverado. While I was at it I adapted all the A/C parts from the truck. That stabalized the nozzle temperature but cut down the air flow considerably. I finally determined that the resriction was in the evaporator. The truck evaporator has considerably more restriction than the original Ford unit. The obvious answer would have been to use the truck blower but it turned the wrong way. It took three days of research before I finally figured out, quite by accident, that the information is in the fourseasons website, something that apparently their tech help does not even know. I looked on the motor for information and there is none but I did find a manufacturers sticker. Monday I will contact the manufacturer and see what they can tell me. Story of my life lately. No matter what you do you will find at least 3 or 4 things you never thought about.
 
Ahhh, so it's a totally modded car. Well I'm sure if you've done all that conversion a simple fan controller will be a walk in the park. Post up some pix for us sometime :)
 
Conversion to a fan controller not so simple when you don't know the answer to the always asked questions like "hall effects" and all the others. I have sourced all the hidden places I have found but that information seems to be top secret. Looking through the fan I can see three sets of coils and there is nothing behind them, but I don't know what might be hiding under the motor cover and I have no intensions of finding out. Hopefully tomorrow I can get some information from the motor manufacturer. Electricity I understand completely but this has crossed the line into electronics which I have never taken the time to understand, and at my age I don't need any more trash invading the few brain cells I still have working.
BTW I visited your country and what I saw of it I wouldn't mind moving there. America has become a bit strange but that is a subject for another long conversation.
 
OlderGiantFan, If you are interested in the Pontiac build go to the Forever Pontiac Forum and click on the how to forum and scroll down to L83 and 6L80 in 63 Pontiac. It is pretty detailed about the build.
 
Probably the first thing needed is to see how many wires the fan motor has. If it has three main wires coming out and it appears to be a fairly normal brushless motor, then hook up a VESC--good chance it can run it.
 
Automotive 'brushed' blower motors will typically consume around 15-20 amps on 13Vdc - 200-275W. BLDC motors will likely consume about the same amps or slightly less - depending on the controller and RPMs set at. A DC clamp amp meter can confirm amperage with a quick bench test.
 
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