AC/Heater fan stopped working

I need some help in this topic, I went off roading recently and somewhere along the way the blower motor went out. Hard to say when, had the windows down for the two days and on the highway back I realized the air wasn’t blowing.
Anyway, I have replaced the Resistor, I have checked every fuse I could think of, I have checked the relay under the hood, and I have replaced the blower motor its self. And I am still getting no power to the motor.
Any help would be appreciated, thank you

 

According to your sig you have a 2018 which would be a 3rd gen, I'd have to pull the diagrams to see what to check.
Also it matters if you have automatic dual zone or manual single zone temp control.

 

I’ve got the single zone manual AC system

 

Ok I'll have to look up diagrams tonight and see, I'm not familiar with the 3rd gen HVAC system.

 

Thank you so much, this issue has been driving me crazy!

 

Looks pretty much the same setup as 2nd gens use.

Power comes from the HTR Fuse (50A) in the underhood fuse box, through the HTR Relay, through IS5 (above right kick panel) Pin 4 (Red), to Pin 2 (Red) of the blower motor.

Ground comes from Ground Point IC (right center of dash) to a splice, one line goes to the Blower Resistor (low) (White/Black) and the other goes to the Blower Switch Pin 6 (White/Black). Depending on the speed selected it goes through the switch and/or resistor to Pin 1 (White) of the Blower Motor.

On Low speed ground goes direct through the Blower Resistor (In on White/Black, out on White).
On M1 speed ground comes from the Blower Switch Pin 7 (Green) into the resistor (Green) and out on White.
On M2 speed ground comes from the Blower Switch Pin 4 (Blue) into the resistor (Blue) and out on White.
On High speed ground comes from the Blower Switch Pin 3 (White) directly to the Blower Motor Pin 1 (White).


If your missing power and your HTR fuse is good I think I'd check the IS5 connector for a burnt pin.

 

Thank you so much, I will give this a shot this afternoon, hopefully I can find whatever the bad connector is and don't have to shell out some cash to a shop.

 

I went through and checked IS5, it is solid. I checked continuity between it and the relay, all good. I bypassed the relay and it works as it should! I checked all the pins on the relay and it looks like one side of the switching circuit is not getting ground from the fuse box.
Any idea on how to solve that?
Thank you so much for your help

 

At the relay:

Pin 1 is Ignition Power from the IG1 No 2 Fuse (10A)
Pin 2 is supplied ground from the Blower Switch Pin 2 (Yellow) through Connector IA2 Pin 4 (Yellow) to turn the relay on.
Pin 3 is power out to the Blower Motor Pin 2 (Red) though Connector IS5 Pin 4 (Red)
Pin 4 is constant ground
Pin 5 is constant power in from the HTR Fuse (50A)


So if your missing ground on Pin 2 you need to check the blower switch and connector IA2.

 

Good troubleshooting bypassing the relay contacts. It does sound like a switch defect at the moment, or since it appears the resistor varies the ground voltage, so could that be a potential cause for no ground? You wouldn't think a Gen 3 resistor could be bad already. But maybe not out of the question.

@Dm93 - should we be able to select, view or download the attached files? I see them but it appears only to be an image. I've saved some before in other threads for reference.

 

The ground to turn on the relay is a separate circuit from the resistor circuit, the blower switch should ground the relay circuit on any speed except off.

Yes the attached files should be able to be downloaded.

 

I did hit a series of very large humps while off roading, that could have something to do with it.
Now that I know the connector is by the driver kick plate it makes more sense, because I have tons of accessory wiring in that area so I may have knocked something loose.

 

After a full day of trouble shooting, and reading wire diagrams, and checking connectors, and trying to figure this whole switching system out. I disassembled my entire dash to check out the blower switch and it was all good. Fed up and confused I decided to try again tomorrow, I put everything back together and lo and behold my blower motor is back to business as usual!
I don't know if it was me messing with the blower switch or all the connectors but thank you for your help I greatly appreciate the community here

 

Well that's great the time it took to disassemble the dash was worthwhile! I've seen photos (I think by Dm93) with the dash off, quite a feat do do and put back. Maybe the actual fix was unplugging and plugging back in a Molex plug/socket.

 

Lol that worked should probably pull it apart though

 

Every 5 or 6 years it needs a good luck slam. Other than that… it’s good

 

Just had an issue where my blower motor would work some days, and some days it refused to turn on. I found a little trick, if you take your air filter out and manually spin the blower motor blades around a few times and then start the truck it works.

not sure how but this works for me.

 

You should really check all of the electrical connectors. If they are all good, then you may need to replace the blower motor.

 

I have been following along with the threads with regards to the blower motor/resistor and I have had pretty much all the same issues over the last few years. I probably have gone through 4 or 5 resistors and the connectors. I took the fan out twice to clean it out, as you all have said black and copper-like stuff came out. Last week it just completely stopped, no losing a speed or two, just stopped. I figured it must be the resistor again as I do slightly remember a hint of burning something in the Truck. That being said, I ordered a new fan and resistor/connector. This morning I got to changing out the parts. Now all I have is high speed. It even stays on high when I disconnect the resistor. Any ideas on what I should try next? It's getting cold up here in Southern Ontario and I am sure going to need my heater to work properly. Thanks everyone.

I have left the resistor unplugged and the fan still works, only on high speed though.

 

High bypasses the resistor so go to the resistor connector with a test light and see what's missing on the other speeds.

https://www.tacomaworld.com/threads/2nd-gen-information-diagnostics.784008/#post-28042158