Air conditioning set to HI, not heating

[Formerly]

Here's a new one - never had issues before but the other morning it was cold out and I had to leave earlier than the usual preset time and the car was fogged up. I put on the heat as I was pulling out and it never got any warmer along my 10 minute trip. Later that day, I drove again and same thing - HI (or any elevated temperature, for that matter) doesn't engage heating. AC seemingly works fine. Vent location changes works (feet/body/dash). I think preheat works too, but I'll retest that to make sure. Seems like a glitch as opposed to a fuse or something. Will report back on the preheat

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[Heliian]

Did you push the max defrost button?

 

[Formerly]

I will try and see if it has any effect and report back!

 

[TaxmanHog]

Curious to know what the results of a departure timed warm up or climate remote start gets you, make sure to set prefered condition WARM if using the departure timer.

This time of year the weather is schizophrenic, ranging from 50's to 90's, I'm only using remote climate start as needed and customizing each session base on the weather conditions of the hour & day

 

[Tfarrell73]

Check your coolant level to be sure fluid is flowing to the heater core

 

[Formerly]

Did you push the max defrost button?

It was not selected, good thought though

 

[husky10101]

Seems strange Ford set it up this way but you have to hit the Heat button on the page where you set which vent you want, defrost, floor, etc. if it is not highlighted. Last winter every once in a while I had to turn on the heat by pushing this button when I didn't have any heat. Give this a try.

 

[RocketGhost]

Check your coolant level to be sure fluid is flowing to the heater core

I don't think the truck has a heater core. The coolant loop goes through the battery and motors to a chiller to exchange heat with refrigerant. I could be wrong but I don't think there's another heat exchanger in the cabin air flow path. Cabin heating in 22-23s is electric resistive.

 

[TaxmanHog]

I don't think the truck has a heater core. The coolant loop goes through the battery and motors to a chiller to exchange heat with refrigerant. I could be wrong but I don't think there's another heat exchanger in the cabin air flow path. Cabin heating in 22-23s is electric resistive.

Not correct, there is a conventional heater core, the electric resistive source is the PTC which superheats the glycol

 

[RocketGhost]

Not correct, there is a conventional heater core, the electric resistive source is the PTC which superheats the glycol

So I guess the PTC is also the means in which the battery is heated? I would think that if it's sole purpose is for cabin heating it would be more efficient to heat the air directly.

 

[Adventureboy]

I don't think the truck has a heater core. The coolant loop goes through the battery and motors to a chiller to exchange heat with refrigerant. I could be wrong but I don't think there's another heat exchanger in the cabin air flow path. Cabin heating in 22-23s is electric resistive.

Low coolant seems to be the number one cause of heater issues. The tank is visible on the driver's side under the frunk trim cover, and it can be inspected without removing the cover. If the tank has yellow coolant in it somewhere around the 1/2 mark, it should be good. If you've had a battery module replaced, it is not uncommon for air pockets to work their way out sometime later and cause the tank to show comple empty. Some, if not most, trucks shipped with air pockets and had to be topped up after only a few weeks (mine and many others).
The truck has a diverter valve system that channels the flow between battery and cabin heat and the cabin heat is on top so it is the first to run out of coolant. This diverter valve system has also been known to cause heater issues.

 

[Formerly]

Hello all, so this morning the truck warmed up great with the scheduled departure feature. The second I start driving, it stopped. I'm thinking software related!

Aside from that observation, the coolant level is fine, checked yesterday.

 

[TaxmanHog]

So I guess the PTC is also the means in which the battery is heated? I would think that if it's sole purpose is for cabin heating it would be more efficient to heat the air directly.

Yes, there is a bypass / diverter which routes the heated fluid to the battery pack in cold conditions.

 

[Formerly]

Check your coolant level to be sure fluid is flowing to the heater core

It's above the min fill line, good thought though!

 

[Adventureboy]

It's above the min fill line, good thought though!

You'll likely need to investigate any codes the truck may be throwing. If you have the OBD2 gear, you can read it, otherwise, it may be a trip to the dealer.

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