How to Test a Blower Motor Resistor Pack.

[@guillaumegiroux9425]

Thank you sir, I learned so much. Indeed, I can confirm my resistor is blowned up. Time to replace, although I want to find the culprit. Thank you again!

[@AdamMechanic]

My pleasure. Glad it has helped you out. Thanks!

[@paulclark4668]

Excellent no nonsense explanation and diagnosis.😊

[@AdamMechanic]

Cheers, thanks for the kind words!

[@gursisingh1940]

I see that you ve been replying comments so worth a shot. Good explanation there but I am a little confused on mine. My motor doesn't work on any settings 0, 1, 2, 3, 4, none of them. I pulled the motor out and hooked it straight onto a 12v battery and it spins fine so I guess it was the resistor. I hooked a multimeter to the cables that go to the motor and and setting 0 I read no volts so thats fine, on setting 1 and 2 I read 8.5v and on setting 3 and 4 is its 12.08v. Motor should work on setting 3 and 4 isnt it but it doesn't. Confusing

[@AdamMechanic]

Hi, so you have changed the resistor and now it’s only 3/4 that don’t work? So, some systems have separate relays and fuses for low and high speed settings. One relay could be powering 3/4 setting. I know you are getting supply voltage, but under load/ high current draw it could be failing. I’d probably go there next.

[@gursisingh1940]

@AdamMechanic it was the blower fan, it would start spinning sometimes if given a push by hand. I ended up replacing both blower fan and resistor and only cost me £40 so cant complain at all

[@AdamMechanic]

Ah OK, so the motor shaft just got a little rusty and was causing high resistance. Cant beat a cheap fix, good work!

[@javier2565]

Perfect this kind of videos have to be viral

[@AdamMechanic]

Thank you!

[@frankandtube]

I believe 0.4 ohm is position 3, 1 ohm is position 2 and 2.5 ohm is position 1. position 4 does not involve the resistor pack.

[@AdamMechanic]

Yes, the higher the resistance, the lower the speed setting.

[@georgemcmanus5943]

Great information. Thank you. New sub. 👍

[@AdamMechanic]

Great, glad it was helpful! Thanks very much for the support!

[@tomnaquin8903]

The little green fuse could be blown.

[@AdamMechanic]

Yes, that could also be true.

[@kevinarnott1172]

Hi Adam, are you aware if a 2013 ford galaxy resistor needs calerbrating

[@AdamMechanic]

It shouldn’t do. They are normally just plug in parts, not intelligent or needing programming.

[@kevinarnott1172]

@@AdamMechanic thanks Adam, it's clearly a duff one then.. warranty claim

[@camperp195]

My fan has just stopped working full stop,1,2,3,4 nothing at all,fuse is ok,will it be the resistor gone?

[@AdamMechanic]

Could be, but more likely the relay, blower motor or a wiring connection/ earth.

[@spudkiss1984]

What if resistor n blower got no power relay n fuses are good

[@AdamMechanic]

Hi. I’d probably unplug the blower motor itself next, turn it on in the car and see if voltage is getting to the motor with a multimeter on the connector side. If 11.5- 12v is getting that far than it will be the motor itself that’s gone. Please subscribe if it’s helpful! Cheers.

[@AdamMechanic]

Other things to check are bad connections and earth, then probably switch after that. Cheers

[@andylasers7288]

Hey Adam, How does the full speed connect to the blower, by a relay? I have all the slow speeds work on a 2008 Kangoo but the full doesn't

[@AdamMechanic]

Hi, it would go through the same relay as the other speeds normally. Sounds like you have either high resistance in the motor itself, or the wiring leading to it. One of those is not allowing the motor to use the full 12v

[@andylasers7288]

@@AdamMechanic Yes it looks like that, but I cannot find the route of the cable from the knob to the blower. I tested the blower direct with 12V it is fine of course seeing that it works at the slower speeds. I need to see a diagram really to follow those cables and see if another connection exists somewhere.

[@shanedowley2877]

Getting a reading of •3ohms on one of the pins is this bad

[@AdamMechanic]

That is probably ok. The fact you’re getting a reading tells me the circuit is complete and should be functioning fine. What is the symptom/s you are trying to solve?

[@zalanocsko154]

hi, so these resistors form a voltage divider? and do they regulate the voltage to the motor or the current? I read about current regulation in many places, but according to my knowledge, the speed of dc motors depends on the voltage.

[@AdamMechanic]

Yes, the resistors restrict the amount of current technically (we rate it in voltage just for ease of understanding) allowed to pass through each branch. So 12v/ same current comes in on all branches/ speed setting but only a set amount is allowed through the resistor to the motor. Please subscribe if your finding the videos helpful! Cheers

[@zalanocsko154]

@@AdamMechanic thx. so the voltage technically does not change. but because the resistors are connected in series in front of the motor, so they add to the internal resistance of the motor, which results in a lower current if the resistance is higher?

[@AdamMechanic]

Yes, you’ve got it! Thanks for the sub, much appreciated!

[@Amicheliche33]

Talk too much.. just get to the point here bud..

[@AdamMechanic]

Noted!