Where do you set your HVAC controls ??

Still digging

 

My 2017 SR5 6CYL Double Cab 4WD has the PTC relays.

 

I didn't realize that there was 3 relays. I thought there was one.

 

Ok I see 3 there too, and it was in place....the "S-Horn" spot was empty.

Also the fuses are in place for each relay too, 1, 2, and 3.

 

What the hell is a S-Horn?

 

Is that for an alarm system maybe ?? Horn and S-Horn are two separate fuses.

 

I thought the alarm used the regular horn. I dunno.

 

I noticed that as well.. i just thought that's how the notches are made.. So if you have it on a setting between two notches will it do a combination?

 

Well anyway those PTC relays are fused 50A, 30A, and 30A.

 

Yes. Just more blending. I can feel the difference when driving barefoot.

 

Pondering that the two 30 amp fuses and associated relays are for the heated mirrors ?? And the 50 amp is for the PTC on the heater core ??

 

I haven't t had a vehicle in quite a few years without an "auto" setting like my new Taco lacks.

I find that the lowest setting blows too hard and I am left wishing there was an even lower setting a lot of times. I wonder why they could not have made it a twist knob instead of notches that are spaced far apart. Odd!

It is pretty amazing though even if you turn everything totally off and just adjust the heat for hot will still blow hot and unless it's freezing outside, like on a cooler morning that's all the heat I need and it still blows hot without the fan.

 

Typically heater motors use staged resisters to control fan speed. Wayyyy back in the day I had a 1978 Caprice that had about every option avail on it, must have been a salesmans demo car maybe. Most stuff back then had 3 speed blower resisters, that car had 4-5 speeds, and it had a thermostat you can just set for temp....you still had to pick Heat,Defrost, AC, or Bi-Level.

With the high amperage that heater motors pull adding infinite speed control would be quite expensive and maybe failure prone ?? The stepped resister setup just fails "open" usually, and you lose a speed, and still typically have the highest speed avail.

Bill

 

But an "Auto" setting on a higher trim has infinite settings I would assume to constantly adjust (heat or cool) depending on selected temp as needed on any given day. I fully understand that's why you pay more for that feature but most cars (thinking of one of my explorers at work) has like 8+ setting on the fan knob...

 

We have had three cars with ACC. Only one worked well enough that I was generally comfortable to let it alone. The other two took about as much effort in adjustments as a good, manual system like in the Taco. I am completely happy with it other than not having full control over the A/C switch.

Yes. I generally have the fan set to Low (one setting above Off). It spreads enough air / heat around unless I have the windows down. Off will still allow air to move, it is just governed by airflow from outside.

 

IMHO it is just a matter of staging more resisters that can be used in combination. The down side is that if an R fails that is used in several combinations (guessing here) then you would lose more than 1 speed. For smaller motors like a PC fan they use something called PWM to control speed. Most of the industrial speed control stuff I work with is pretty expensive overall.

On the blend side of things to control temperature a lot of that stuff is vacuum controlled ??

I know a friend just got a Tundra and he was getting cold air flow out the dash vents with fan off before engine coolant temp had come up and there was some control feature to shut that off, holding a button down (recirc maybe ?).

Bill

 

Either way I find that the lowest blower setting on the fan blows too hard for me. I've owned many cars and trucks and never really had this issue. I wish there was a lower fan setting and there should be but isn't. Whatever though as I opted to not spend the extra money for the higher trim and will have to live with it as is and just continue to adjust the temp control more.