How Blower Motor Resistors & Fan Speed Controls Work • Cars Simplified

[@judgewindaniel3713]

Thank you!!! This video was very informative!!

[@amypiero]

Hi Sir.. I have an issue with my Toyota Wish 2007.While driving all of a sudden my aircon and its panel went off.Later i check the radiator fan also went off. I went to sent to a mechanic....he change for me a fuse and it went back to normal.Today while driving same thing happened again. Went to another shop , he checked whole day but unable to find the fault. Can you help me and guide me what is the main problem? Thanks

[@bendeko]

Just the info i was looking for .thnx😁

[@CTRadventures]

We are restoring an 09 civic. I just replaced the blower motor, the ac and settings work fine, however, I'm trying to get the fan to flow faster on high. I am not sure if it will even change anything if I got a new resistor as adding a new motor didn't

[@CarsSimplified]

I assume you've checked the cabin air filter? To make sure the blower motor is getting full power, check the battery voltage and then check the voltage drop across the blower motor while on full power. I don't currently have a video on back-probing with a multimeter, but that is probably the easiest way to test it. If the voltage is considerably different between your car's power and what the fan is using, then there is something in the fan circuit that is adding resistance. It could be the resistor unit, a bad ground, or some damaged wire. Depending on the design, the switch could be not switching to the full speed. There are other things it could be, but these seem like the most likely.

[@CTRadventures]

@@CarsSimplified yup I have replaced the battery, blower motor, and cabin filter

[@scottmcnabb5323]

Thank you. Learned a few things. Appreciate the info.

[@germplus]

Hello I installed a webasto parking heater and its capable of turning the car blower fan on to warm the car before I get in. However I’m not sure where to wire up fan to the Webasto unit. Will appreciate your help. Thank you.

[@poolbump1234]

would a bad resistor causes the speed control to be out of sequence?. on my van it seems that the 3rd setting is the lowest, while 1, 2 and 4 would increase the fans speed accordingly.

[@ryanwyrick6947]

Thanks bud do you or anyone in here know if I have a weak blower fan on number 1 and 2 but 3 seems to be strong, could the resister make 1 and 2 weak and 3 not weak? Also note I have a 98 F150 and do not have the cabin air filter mod. They didnt come with cabin filters so you can make a 2 inch wide 10 inch long cut on the air box and slip a filter in. I bring this up because there could be restriction from debris and I feel like the number 3 is a strong fan but maybe the air held back a little from debris. Numbers 1 and 2 on the knob seem to be very quiet and very weak. Number 1 isnt even useful.

[@tonyacook7614]

Thanks for sharing and I hope I can fix my heater/defroster as it is in the negative temperatures here in Alaska

[@TheDarkitox]

Fast, Concise and to the point, you get a like and subscribe.

[@tomcrawshaw6115]

Thanks. Great explanatory video!

[@felachhangte3820]

Sir my car blower works only for sometimes. It blows and stop, when it stopped the speed controller hasnt works. Totally stop working. When i check Resistor i found some rust on it. Can it be the cause of mulfunction of the blower?

[@CarsSimplified]

That could be the problem, but with rust I would make sure there aren't any liquid or moisture problems like a leak that will damage the next blower motor resistor, or that is already causing problems elsewhere.

[@felachhangte3820]

@@CarsSimplified Thank you sir

[@agusado07]

Thanks for the video, what could be if when I set the speed to 3 or 4 the speed of the blower decreases and increases in intervals of 10-30 seconds? sometimes the speed stays constantly when suddenly decreases and once again increases.

[@peteronoka128]

The AC unit on a Toyota Hiace 16-str van has the front & rear vents. The rear AC blows fine cool air; however, the front has air blowing out but not as fast as the rear vents.

[@justsoblessed]

Theirs no power going to the fan control dial, but theirs heat upbeing blown out of the vents. And I can’t turn the heat off. I have a 03 Nissan Maxima, and the heat stays on high no matter what. The knob doesn’t work at all, it’s not letting me turn off the heat. Do you know what that could be ?

[@TOMRYANLUKE]

Thank you for making this video. God bless you.

[@karenjackson6100]

Have a 2006 commodore , 1,2,3 work fine 4 nothing at all, replaced resistor and still the same, any idea, thanks

[@JackalsGOD]

I have the same issue started to look at it today. Replacing the resistor fixed your issue ? thanks

[@edmundabner9956]

Will it be okay if the aircond cleaner foam get to that thing? Will it broke the resistor?

[@pallavikiragi8481]

Hi do you know the approximate speed of airflow or motor speed for each level of the air conditioning dial(1,2 etc)?

[@CarsSimplified]

I unfortunately do not have that information, but I do know this will vary based not only on the car, but which vents are selected, how many selected vents are closed, wear and tear on the blower motor, and even the type of cabin air filter being used. (All of these mostly alter air flow but also slightly affect fan/motor speed, too.) Are you just curious or working on a project of some sort?

[@dee1380]

When I select floor, the blower turns off. Works on other settings. I put another selector in, it did the same. It has a new resistor as well.. Goes from cold to hot.. Any suggestions?

[@SuperRefractorman]

Thanks bro. Exactly what I was looking for.

[@juliusipock2979]

I have a question I have a 03 Chevy avalanche I replaced the blower motor and the blower motor resistor 3 months ago the blower motor completely quit yesterday I put on a new blower motor resistor this morning the blower still wouldn't work so I pulled the blower motor out and bought a new one it wont work either there are 2 wires coming out of the blower motor resistor red and black that plug in to the blower motor the red wire has power at settings 1-4 and the black wire has a little power at setting 5 no power on red at setting 5 What could be my problem I took a wire and clipped it on th post where the black wire would go on the motor Hooked it to a bolt under the hood and took a wire connected it to the positive on the battery and touched the end on the post that the red wire would go on the blower motor and nothing I did it to the old motor and the new motor neither one would spin are both motors bad or is something else wrong

[@mattmgarza]

This is alternate universe TJ Kirk. This is a very informative video. Thank you.

[@diveshsingh5425]

Thank you!

[@minebloxralsei8110]

I have a Honda Cr-v 2002. The AC is not blowing enough cold air. Ac air compressor is new, fans are working and it has enough freon. One friend told me it might be the blower motor resistor...is that a good or bad guess?!. Help!:(

[@Switching-Cars]

my ca and heater is not working on any speedd and i just replaced the blower resistor so what do i need to check next? the fan controller switch ?

[@richardv3327]

Hey what's up nice video my question is that all my settings are working one-two-three-four all that I got a 2014 Nissan so my thing is why why does my speed very depending or doesn't matter what number I have it are number one or full speed the air pressure keeps going up and down why I am literally writing you this in the car with the AC on

[@GeorgeAugustine-j6q]

Is there a way to reduce the fan speed? My low speed is too much.

[@marvinbarnardvillardo3401]

When I open the aircon and put IT ON number 1. IT is not working. But when i put IT ON number 2 or three. IT started to blow air. When I returned the knob to number one IT is now working. I changed the resistor block. It has the same problem. Maybe the selector switch is malfunctioning. Honda Jazz 2012 ni the Philippines has this problem

[@detectorgadget]

Nice video. I learned something.

[@TheRFamily5]

Hi, I have Rover 45 (2004) 1.4ltr club SE petrol. my fan blows on full speed and temperature setting wise all works fine. I just can't stop the fan or reduce it to the lower level.air con settings all works as desired. could it be the time to replace my resistor? as it's very annoying to have the fan on full speed as i turn the ignition on. please advice. Thank you.

[@CarsSimplified]

While that could be a resistor, it sounds like it may have a short or someone wired it up to bypass the resistor and switch entirely. If only you have access to it and it just started doing that, it may be the resistor then. Otherwise, it is most likely a rewire job to quickly avoid another problem.

[@ezequielparra1854]

What would cause my fan to surge and fluctuate speeds from high to only low? Car is too new 22 WRX and 20k miles

[@rydaug79]

My resister did burn up on my chevy silverado. Only fan speed 4 out of 5 was working. I replaced it and 1,2,3 and 4 now work but 5 still does not. Any Ideas why? Also the green stick circuit board looking thing that comes out got really hot when I connected it. I was thinking, since it sticks up into the air vent, that is what cools it. And because it was on but the fan wasn't blowing, that is what made my old one burn up. Is that the case or should it not hot?

[@CarsSimplified]

That is what cools it, but unless you connected it with the fan on (not a good idea unless you are running a quick test) it shouldn't be getting hot. If it is getting hot but your fan is turned off completely, you may have a short that is burning up your components. You may even have a shorted blower fan motor winding. Try testing your connectors with all power to the fan off (but vehicle key on) and see if anything seems to have power. Before doing that, check to see if the blower motor circuit has a fuse, and if so, if it has the correct fuse.

[@ehodzic155]

I suspect my problem might have something to do with the resistor. But its not like you described. Thing is my fan broke down. And after replacing it all 4 setings WORK but they are noticeably slower than before. however sometimes when i put the car in reverse it works just as fast as it did before. Its such a weird problem

[@armanrivera4116]

i replace the ac blower resistor every year.. is it OK to just remove the resistor and just use the AC on max fan speed at all times? i live in a hot place anyway, most of the times, my AC is set to 3.

[@CarsSimplified]

Yes, you can do that for sure. Top speed on a normal fan switch is the same as what you are suggesting.

[@Mrm0nkiii]

Awesome thanks. I learned something. You may have save me some $ and a lot of time. I never fully understood what I was doing just replacing things. Now the concept makes sense.

[@cliffordsaayman9762]

Still need to know how to remove blower on righthand drive 2006 nissan micra?please if anybody knows.

[@chandrapoudyel4904]

ac blowing but only one direction, when I change to different direction it will blow still same...help what I have to do ...1999 toyota camrey

[@asaifpathan3618]

In my car the 3rd position speed is low as compared to 2nd position, suggest that is the problem. Again there secpred blower register for 2 blowers.

[@misheedawn3214]

Thank you. This helps. I hope mine is this easy of a fix

[@kingofkisses2008]

Thanks, short and sweet

[@marioatrucking]

I have a 95 Kenworth with 3 speeds. Can I replace it with a 5 speed resistor to make it go faster? Like a more modern ac system? Thanks in advance

[@CarsSimplified]

If both resistors get their top fan speed by having a selection that just bypasses resistors, both the three and five speed setting resistors will have the same fastest speed. I'm not familiar with what Kenworth uses but if it is the same design as cars use, it will be how I described. If you can find information on the parts, see if they both have a 0 ohm (or very close to 0 ohm) path; this would tell you for sure that both top speed settings are the same.

[@williamnajera8666]

so my subaru heater is constantly blowing full speed once the key is on ACC. temp control works, vent selector works, but the off to full blow selector does nothing. on or off, it's blowing full speed. HELP

[@CarsSimplified]

It sounds like something has shorted past the blower motor resistor and is supplying power to the blower without setting consideration. Were any electrical repairs or modifications performed recently? The dial that actually changes the setting for the fan speed may be internally stuck on full, too.

[@williamnajera8666]

@@CarsSimplified the guy i bought it from said he did something to keep it on, being Alaskan winter. Im really not sure what all he did to it. Im gunna pull the dash off and take a look in there.

[@CarsSimplified]

Ah, interesting. That may have started because of another problem (no need to bypass stuff if you could just leave it on the maximum setting) so it may require more effort than just putting it back to stock. As for what to do, I would start with checking to see if there is an out-of-place wire going to the blower motor. Since it only runs when the car is turned on, the fan or blower motor relay may be tied to something else that is also only on at those times. Best of luck to you! Custom wiring jobs are often a pain.

[@williamnajera8666]

@@CarsSimplified so i took it all apart to look, and found the issue. The wires to the fan speed selector switch are all cut. Ill likely have to just get a new control panel, i havent found any info on if i can just replace the switch itself. Couldnt get the plug out.

[@noelleschmickel6737]

I have a Nissan versa 2009 and no air comes out of vents blower was tested it blows fuses cked all ok what else could it be?

[@CarsSimplified]

If you know the blower works, but the correct type of fuse blows out when you try to run the fan, the most likely culprit is a short. Fuses blow when too many amps pass through them, so there can only be a short or too much load. Are there any burn marks on the plug?

[@CarsSimplified]

Oh, sorry, I misread your comment. Can you hear the fan turn on at all? Sometimes debris can get into the fan and/or cabin filter, stopping air movement.

[@knucklesammich6313]

Ac blower motor goes out or is on very low setting, so i replaced motor thinking it was the motor. It is still randomly going off or is low, i replaced the connector that connects to blower motor and the resistor still happens. Took it to a mechanic and told him what was replaced he checks voltage and relays everything was good. He tells me since i did i replaced those parts and that how the blower motor is very low or stops blowing completely that it was the climate control module. So i ordered it off from ebay cause the dealership do not sell that part. I replaced it and still the problem persist.

[@Youngkaibands1990]

thank u i did learn

[@traceycraig4137]

Neat. Told me what I needed to know.

[@RudyRivera60]

Would it cause all of the settings not to work?

[@CarsSimplified]

It could, but that is much less likely than a bad blower motor or a broken/disconnected wire.

[@RudyRivera60]

Cars Simplified i have a 2005 nissan murano a/c jus stoped blowing i checked blower fuses there good, i checked blower relay its good, i changed the blower still no luck, the last thing i could think of is the resistor but it doesnt work on any settings, do you think that could be the problem ? Thanks for the quick response

[@CarsSimplified]

It could be, but also make sure there is no fuse for the HVAC controls and make sure the wire harness isn't melted. I had a loose wire on my own car cause that same problem and I had to replace the plug.

[@RudyRivera60]

Thanks man will deffinetly check the hvac fuses

[@นายอินขอรับ]

Thank you

[@rigohernandez7096]

kia sportage 2006. I have no air at all .but the ac light turns on..

[@CarsSimplified]

By no air do you mean nothing cold or nothing blowing at all?

[@rigohernandez7096]

No air blowing at all

[@CarsSimplified]

It seems like you came to the video discussing the two right things but it is difficult to tell for sure. Least expensive route for DIY is to pop the blower motor out and see if there is anything preventing it from moving. While it is out, see if the fan spins under car power, then direct power (be careful with that) if it fails that.

[@CarsSimplified]

Fan spins under car power, but only out of its housing: likely a bad wire or something stopping the fan blades. Fan spins on direct power, but not from the car's plug: you will have to chase down an electrical issue. My least favorite. Nothing spins the fan: the fan itself is damaged somehow.

[@ballysautodrivingschool2962]

what if fan motor work sometime sometime does not work is the resistor not working

[@vantime2911]

most likely you have a bad motor, loose connection, or there is a connection that heats up and has started to melt and is causing this intermittent problem. There should be three areas for connections you will want to check. 1st. at the switch on the dash, this will require pulling the switch from the dash and looking behind it to see the connection. 2nd, is at the resistor. This can normally be found somewhere near the motor and attached to a vent tubing that flows the air from the blower. (Resistors heat up this is why they are placed in these areas. It helps to keep them cool). 3rd is at the motor. Normally found under the dash on the passenger side or from inside the engine compartment on the passenger side firewall.

[@toddh6234]

Depending on how the resistor breaks. The A/C and Heat may only blow at certain speed settings or it may not blow any air at all.

[@highfamily8292]

Thank u bro

[@jenniferkimnguyen6140]

thanks

[@lucilleharrell477]

Heater on &off on when light touch gas pedal.idel heat off.

[@mascalientequeelsol7159]

Good

[@kavindugilshan]

why don't they use PWM to control fan speed .. more efficient than resistors ... ?

[@CarsSimplified]

I imagine resistors are less expensive and they aren't too worried about about energy efficiency. However, I wouldn't be surprised if some new high end cars have fan speeds controlled by pulse width modulation.

[@MrRein1988]

You did not explain how heater resistor works, did you? You just said what it is involved in. How it works generally means explanation of inner workings.

[@aqib2000]

Completely agree

[@markvermeulen1372]

A resistor consumes / reduces some of the voltage. The remaining voltage is applied to the motor brush’s. Therefore slower speed.

[@acegunsncars]

I need that shirt

[@rezagrans1296]

All speeds but max have went off. Im hoping an automot scrap yard'l have a good one and not charge 35 to $50 (the car will barely $ell for $900 iF im lucky*); stupid tuf reneging buyers nowadays, scratches from scraping ur windows and body painylt due to bullsh canadian cold winter, and depreciation of a 2000 2.2l l4 o.h.v Sunfire by GM pontiac

[@nicholaslynch7651]

# subbed

[@Goldtuno]

thanks