Testing Blower Motor Amperage and Voltage 

I needed these general specs for an automotive blower motor for a project. This video was a massive help to me making a diy fan speed control. Many MANY thanks!!

Thank yuo Mr Richpin. Crystal Clear as the living water is this video. You give me a wealth of knowledge.

Thanks, only video with this info! My blower is getting a hot postive wire, 15 amps! Now I know it should give about 10 amps.

A very clear and helpful presentation. Well done!

Thanks , great video. Just what I was looking for.

Never ran into a problem were the A/C would blow colder while the vehicle was turning.But it is normal for reduced cooling while standing still because of air flow over the condenser.

I dont know much about electrical testing so am confused about your set up. Looks like you just put those jumpers any old way. does it not matter which jumper goes to ground and which to power on the connector and the motor??

This helped me a lot. Thank you for making the video.

If the motor is on the way out, what type of readings would you be getting? Thanks much for the video.

Hey I got confused can u explain to me what type of wire going to the blower fan I’m assuming one of them is positive and the other in negative or this incorrect?

@widtrak77 These are the correct figures for a normal operating blower motor.

@mattcasdorph If you can get at the metal housing of the motor you can check ground there or at the motor electrical connector.

@mattcasdorph To check that connector your meter needs to be on the V DC 20 scale and the lead from the meter needs to be in the V plug.

@mattcasdorph You said you had voltage at the connector so if the connection is good it is a ground or motor problem.

@richpin06a Ok, I tried the meter set to 20 DCV and it read 12.15V, I switched it back to 10A and changed the red probe end to the Amperage gauge and it still shows no amperage, but apparently it does have voltage! I know the blower is good, could it be a bad connection between the connector and the prongs on the blower motor?

Probe the electrical connector from the motor with a multimeter to see if you have ground voltage.

If your multimeter is only rated to 10amps you shouldn't be testing amperage that blower motor pulls over 20 amps on full speed hence why it has a 30 amp fuse for it installed on the outside of the glove compartment.

@mattcasdorph As long as the motor is ok no amperage reading should mean no voltage at the connector.

In an 89 buick lesabre, why is it during a turn the air condition blows dramatically colder like it should. It blows cold but not as cold as it should while driving. At a stand still it blows cool! It's fully charged, new compressor and dryer, new tensioner, new belt. The dryer is cold & sweating! & it has a new blower motor. The system is not manual, it's touch. Appreciate a solution if u have one?

k. thanx. I'm noticing now that it's not blowing hard on high. Not hard at all. I'm bout to check the amps!

@mattcasdorph If the ground is good at the connector that would leave just the connection between the connector and motor as a possible problem.

@richpin06a I'm not sure, The last time I tried to check it with the multimeter I wasn't getting a reading, but I may not have had a good connection with the multimeter (using the multimeter probes on flat prongs is a pain), I was going to try to test it again today, but my sister had an appointment and borrowed her car, so I have to wait till afterwards. I guess if I don't get a reading at the blowers connector it would either be hot or ground one that's not completing the circuit.

@richpin06a thanks for the help, I'll check it out again in the morning and update you

Were the amperage readings within normal, acceptable values? What would non-acceptable perimeters be? Expected readings on a new motor, installed with blower wheel? How does resistor affect amperage and voltage readings taken in this fashion?

hi mine car ford, that blower fan does work and neither a/c. and on display if I try to change blower direction, nothing icon showing as well on dispaly suggest me what is the cause I checked already relay of car

My heater blower is not working , what’s the point of this testing if it comes on it works right

My blower motor winding measured 0.5ohm..that means on full speed it can pull 28.8A at 14.4V, way to blow a unfused DMM lol maybe we can try with a DC clamp on meter

mine pulls 13.5ish amps all the way up. that does seem to be quite a bit of work to get this reading. I have a fluke amp clamp type

Did u do that with the car running.

Helpful. Thanks.

My blower motor only works on LOW. Any suggestions. I'm kind of a rookie, but I do have a multimeter.

you have two wires on harness. black and purple. is black ground? it appears your connecting meter to the spade coming from fan that would be ground to the purple wire which is hot. is that the case. I don't want to it backwards or does it matter? Please explain

@mattcasdorph Do you have ground and voltage at that the blower connector.

I'm trying to figure out why my moms heater in her Contour is not working, I took the blower motor out completely and tested it off the battery and it works, and I replaced the Blower Motor resistor and it still dont work, I'm guessing there is either a wiring problem or a switch.

@richpin06a Would it matter that it was on 10A setting? I know that's amperage, but if there was no amperage reading, wouldn't that tell me there is no voltage anyway? I didn't get to test it on the 20 DCV

weather that motor taking amps normal or more..if more then may be got problem in switch or in fuse or in blower resistant

@richpin06a I tried a homemade jumper to make sure the connection was good from the connector to the fan prongs, never got it to come on, I also bought a ac/blower switch and replaced that, and today bought a new relay (the old one had a prong that looked like it got hot before so I figured it may have went bad) and it still does not blow. Whats the switch in the center called? The one that controls gates and defrost ect...

@richpin06a Thanks for the reply. The blower motor in my 1977 GP only works on high-new resistor didnt help. On high it seems to put a heavy load on the system-lights dim and slow blinkers particularly at idle. Is it possible there is excessive draw from this and how can I test if no lower speeds and the meter maxes out at 10amps on high? Thanks for the communication! All other components test good.

What should the parameters be for voltage and amperage. You never mention it!

a rich a have question whats themaximum amperage draw and volts for each speed in general for all makes an models

Could you pleaae share the teating diagram..

HI rich, so what was the Co clusion of the test , the motor is good or not,? I think the voltage drop was too high?

Helpful

@richpin06a the meter on 10A DC setting is not showing anything

@richpin06a I know the motors good, how would I check the ground?

My blower show 1.4 amps on full. Does it sound plousible?

@widtrak77 Thanks for the reply. The blower motor in my 1977 GP only works on high-new resistor didnt help. On high it seems to put a heavy load on the system-lights dim and slow blinkers particularly at idle. Is it possible there is excessive draw from this and how can I test if no lower speeds and the meter maxes out at 10amps on high? Thanks for the communication! All other components test good. widtrak77 2 weeks ago

Hello Peter Griffin.

Can you just do amperage test at fuse

what if i get 12v at the motor but its not turning on, must be losing amps somewhere....

thanks

why the voltage changed ???????

@richpin06a Just checked it, doesn't look like it does.

11.31 volts spike 11.43 AMP

@mattcasdorph No voltage

It's mean this is 75 watts motor

@skyzophrenyk Yes you can.

NOTE inline Fuse AT TEST

Testing Blower Motor Amperage and Voltage is define in this video for useful more information.

20 amps

Hello there.....lol

Pm

Um this isn't a jeep

Sala coment ka jbab tera bap dega jantu

*What was the purpose of doing all this you never explain what the problem was. To me this is a waste of time.*

😂dc or higher never heard of that