Heater not working.

[Jonno21]

There are basically two cooling circuits...Motor/Electronics and HVB/Cabin. The HVB/Cabin is a combo Heating or Cooling circuit where the battery and cabin heater have their own isolated loops that can be combined under certain conditions to share heat when available.

However, the Workshop Manual appears to have conflicting information. For instance:

Cabin Heat

The cabin coolant heater circuit provides warm coolant to the heater core to warm the passenger compartment. A PCM controlled cabin coolant heater warms the coolant. The cabin heater diverter valve allows warm coolant from the electric motor circuit, when available, to enter the cabin heater circuit to provide warm coolant for cabin heat. The upper temperature limit for the cabin heater circuit is 80°C (176°F). An ECT sensor in the cabin heater circuit provides the PCM with coolant temperature information

I believe there is an error in the above statement because the Electric Motor Circuit is separate and does not mix with the Cabin Heat/HVB circuit at any time. There isn't even a heat exchanger that I can see anywhere so I don't see how it is physically possible for the heat generated by the motors and electronics to warm the cabin at any time.

Later in the WSM is a more reasonable statement:

Cabin Coolant Heater

The cabin coolant heater has both low voltage and high voltage electrical connections. The low voltage circuits are used for controlling the unit, while the high voltage circuits are used for heating the coolant. The cabin coolant heater uses electricity, or more accurately, the heat for resistance in electrical circuits to quickly raise the temperature of the coolant to normal operating temperature. The SOBDMC sends power to the cabin coolant heater and controls the LIN circuit to the heater.


Cabin Heater Coolant Diverter Valve

The default state of the cabin heater coolant diverter valve is de-energized, placing the system into the isolated loop mode. Coolant flows out of the valve, then back, in the following order:

• cabin heater coolant pump
• cabin coolant heater
• cabin heater coolant temperature sensor
• heater core
• cabin heater coolant diverter valve

When energized by the PCM, the cabin heater coolant diverter valve places the system into the combined loop mode. Coolant flows out of the valve, then back, in the following order:

• cabin heater coolant pump
• cabin coolant heater
• cabin heater coolant temperature sensor
• heater core
• cabin heater coolant diverter valve
• HV battery coolant pump
• HV battery
• Traction battery coolant proportional valve
• cabin heater coolant diverter valve

What I would like to know is what happens when E-Heat is enabled or disabled? What happens REALLY? I originally thought it disables the PTC heater but now I think it might just force the system into isolated loop mode. When I have time I will try and find the PID for the cabin heater diverter valve and the cabin coolant heater and see what happens when I mess with the E-Heat button. I will have to wait until it gets pretty cold though because the PTC heater really needs cold coolant in order for the resistors to allow current to pass through it. I don't think much will happen at moderate temps but I could be mistaken. Will be interesting to see what happens.
Need cooler temps though.....

I think my head just exploded. Can I take it that if I definitely want warm air I just tap the e-heat button even on Auto?

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[macchiaz-o]

I think my head just exploded. Can I take it that if I definitely want warm air I just tap the e-heat button even on Auto?

If you want warm air, touch Auto then set the temperature where you'd like it to be.

 

[Jonno21]

If you want warm air, touch Auto then set the temperature where you'd like it to be.

Just like any other car then. I was beginning to overthink the HVAC operation.

 

[macchiaz-o]

Just like any other car then. I was beginning to overthink the HVAC operation.

Yes, @SnBGC enjoys the mechanical aspects and puzzling through the cryptic workshop manual enciphered clues.

 

[kdryden99]

Ok so funny enough I was going to post about this exact issue. Here in Montreal, I need to start heating already, we're reaching 30degrees Fahrenheit tomorrow. I remember from watching every single webinar, video, interview, that e-heat should only be used in extremely cold weather and to use the seat and steering wheel heat to warm up the car. That E-heat should be off and that the car's heat scavenged from the batteries in combination with the other 2 would be enough. I set the departure times on the car and low and behold yes the car is warm, my ass is basically on fire, but my feet are cold. Turn on the fan turn with ac as any other car but turn off e-heat. After driving 15-20 minutes no warm air WTF. I figured ok I am doing something wrong so I just need to get used to the way this car works. Let me put the seat warmer to auto. The seat got so hot I couldn't sit. Turned it off. Put on the E-Heat and everything was good.
I can confirm 1million percent with over 100 threads in this forum that we all hashed it out numerous times and 1 sandy munro video that there is NO HEAT PUMP.
And after reading this thread, and my personal experience once it gets close to 30-40 degree mark you need start using E-Heat. The scavenged heat is not enough and using just the seat warmer is fine until your feet get cold and you can't feel the pedals anymore. It wasnt my imagination.

 

[kdryden99]

Interesting enough.....the motors and electronics get much warmer than the HVB. Around 158F according to the WSM. But of course the mass is much less so that heat can be more effectively managed I think.

The radiator in front of the car only exchanges heat with the Motor/Electronics coolant loop. It doesn't get involved at all with the HVB/Cabin fluid circuit. The only time the fluid from the motor/electronics loop comes close to the fluid from the HVB/Cabin loop is at this hose assembly. To me it just looks like two hoses side by side with no valve or heat exchanger so the note in the WSM about sharing heat doesn't make sense to me.

The RWD, Base AWD and GTs each have different plumbing up front. This is the base AWD diagram...

From what I remember the E-Heat turns on the PTC heater

 

[kdryden99]

There are basically two cooling circuits...Motor/Electronics and HVB/Cabin. The HVB/Cabin is a combo Heating or Cooling circuit where the battery and cabin heater have their own isolated loops that can be combined under certain conditions to share heat when available.

However, the Workshop Manual appears to have conflicting information. For instance:

Cabin Heat

The cabin coolant heater circuit provides warm coolant to the heater core to warm the passenger compartment. A PCM controlled cabin coolant heater warms the coolant. The cabin heater diverter valve allows warm coolant from the electric motor circuit, when available, to enter the cabin heater circuit to provide warm coolant for cabin heat. The upper temperature limit for the cabin heater circuit is 80°C (176°F). An ECT sensor in the cabin heater circuit provides the PCM with coolant temperature information

I believe there is an error in the above statement because the Electric Motor Circuit is separate and does not mix with the Cabin Heat/HVB circuit at any time. There isn't even a heat exchanger that I can see anywhere so I don't see how it is physically possible for the heat generated by the motors and electronics to warm the cabin at any time.

Later in the WSM is a more reasonable statement:

Cabin Coolant Heater

The cabin coolant heater has both low voltage and high voltage electrical connections. The low voltage circuits are used for controlling the unit, while the high voltage circuits are used for heating the coolant. The cabin coolant heater uses electricity, or more accurately, the heat for resistance in electrical circuits to quickly raise the temperature of the coolant to normal operating temperature. The SOBDMC sends power to the cabin coolant heater and controls the LIN circuit to the heater.


Cabin Heater Coolant Diverter Valve

The default state of the cabin heater coolant diverter valve is de-energized, placing the system into the isolated loop mode. Coolant flows out of the valve, then back, in the following order:

• cabin heater coolant pump
• cabin coolant heater
• cabin heater coolant temperature sensor
• heater core
• cabin heater coolant diverter valve

When energized by the PCM, the cabin heater coolant diverter valve places the system into the combined loop mode. Coolant flows out of the valve, then back, in the following order:

• cabin heater coolant pump
• cabin coolant heater
• cabin heater coolant temperature sensor
• heater core
• cabin heater coolant diverter valve
• HV battery coolant pump
• HV battery
• Traction battery coolant proportional valve
• cabin heater coolant diverter valve

What I would like to know is what happens when E-Heat is enabled or disabled? What happens REALLY? I originally thought it disables the PTC heater but now I think it might just force the system into isolated loop mode. When I have time I will try and find the PID for the cabin heater diverter valve and the cabin coolant heater and see what happens when I mess with the E-Heat button. I will have to wait until it gets pretty cold though because the PTC heater really needs cold coolant in order for the resistors to allow current to pass through it. I don't think much will happen at moderate temps but I could be mistaken. Will be interesting to see what happens.
Need cooler temps though.....

There is a heat exchanger. Sandy shows it in the episode where he discuses the cooling loops.

 

[SnBGC]

I think my head just exploded. Can I take it that if I definitely want warm air I just tap the e-heat button even on Auto?

Yes. E-Heat will need to be illuminated if you definitely want warm air. I would really like to take apart the cabin coolant heater to see if it is PTC or TFE type. Either way, it seems that turning off E-Heat really just affects the passenger compartment. The car might still use that coolant heater if it needs to warm the battery whether or not E-Heat is enabled in SYNC.

If you turn off E-Heat, then you still might get some warm air either because it's warm outside or there is some heat from the HVB circuit that is shared with the cabin heater circuit. In my car, if I turn off E-Heat, it stays off even after repeated key cycles. These past couple of weeks it has been low 60s F ambient when I leave for work and the car is warm inside because I have it set to pre-condition. When I start the car and back out of the driveway, I sometimes notice that my seat heater is on. Sometimes on really cool mornings the steering wheel heater is on also. My climate is on Auto set to 74 degrees and I feel some warm air but not much. Just barely luke warm I suppose. I check E-Heat and it is still turned off. It doesn't turn on even if I have my climate set to Auto and the interior desired temp is about 10 degrees warmer than ambient air outside.

After about 10 miles, the air coming from the registers is much cooler and feels pretty much like ambient air outside. Again, E-Heat is still off. This leads me to believe that the battery isn't really all that helpful in producing waste heat at those temps. I usually just turn off the climate control at that point because I just have an aversion to E-Heat (something I need to come to terms with I guess....). By the time Jan and Feb arrive.....I will certainly be using the E-Heat to supplement the seat and steering wheel heat.

 

[SnBGC]

Just like any other car then. I was beginning to overthink the HVAC operation.

While driving.....my car won't create any meaningful warm air for the passenger compartment unless E-Heat is enabled. Just leaving it in Auto isn't good enough. Keep in mind that we have seen repeated examples of cars behaving differently so it's entirely possible that your car might work just like you expect. If not, then make sure E-Heat is illuminated and you should be good.

 

[kdryden99]

Yes. E-Heat will need to be illuminated if you definitely want warm air. I would really like to take apart the cabin coolant heater to see if it is PTC or TFE type. Either way, it seems that turning off E-Heat really just affects the passenger compartment. The car might still use that coolant heater if it needs to warm the battery whether or not E-Heat is enabled in SYNC.

If you turn off E-Heat, then you still might get some warm air either because it's warm outside or there is some heat from the HVB circuit that is shared with the cabin heater circuit. In my car, if I turn off E-Heat, it stays off even after repeated key cycles. These past couple of weeks it has been low 60s F ambient when I leave for work and the car is warm inside because I have it set to pre-condition. When I start the car and back out of the driveway, I sometimes notice that my seat heater is on. Sometimes on really cool mornings the steering wheel heater is on also. My climate is on Auto set to 74 degrees and I feel some warm air but not much. Just barely luke warm I suppose. I check E-Heat and it is still turned off. It doesn't turn on even if I have my climate set to Auto and the interior desired temp is about 10 degrees warmer than ambient air outside.

After about 10 miles, the air coming from the registers is much cooler and feels pretty much like ambient air outside. Again, E-Heat is still off. This leads me to believe that the battery isn't really all that helpful in producing waste heat at those temps. I usually just turn off the climate control at that point because I just have an aversion to E-Heat (something I need to come to terms with I guess....). By the time Jan and Feb arrive.....I will certainly be using the E-Heat to supplement the seat and steering wheel heat.

I can confirm at 30-40f the e-heat wants to stay on when in auto or whenever you turn on the front defroster/defogger

 

[SnBGC]

There is a heat exchanger. Sandy shows it in the episode where he discuses the cooling loops.

Okay cool. I will try and watch that then. How many heat exchangers did he show? So far I know about:

1. Main Radiator
2. Heater Core
3. Battery coolant chiller
4. Oil cooler rear traction motor
5. Oil cooler front traction motor (GT)

Is there one more that exchanges heat between the Motor/Electronic loops and the HVB/Cabin loop?

 

[SnBGC]

I can confirm at 30-40f the e-heat wants to stay on when in auto or whenever you turn on the front defroster/defogger

Makes sense. There must be some threshold temp where it gets forced on.
I see in the WSM that the AC Compressor won't be allowed to operate at temps 32F and below so there is probably a temp where Auto simply must have E-Heat to have a chance of even achieving the Low setting.

In my Focus Electric, we didn't have any way to disable the PTC heater. If I just wanted cool air from outside without running the heater than I had to turn off Auto and move the temp all the way to the Low setting. That seemed to work fine. There might have been a better or easier way but I didn't figure it out. ?

 

[kdryden99]

Okay cool. I will try and watch that then. How many heat exchangers did he show? So far I know about:

1. Main Radiator
2. Heater Core
3. Battery coolant chiller
4. Oil cooler rear traction motor
5. Oil cooler front traction motor (GT)

Is there one more that exchanges heat between the Motor/Electronic loops and the HVB/Cabin loop?

If I remember correctly he showed the one linked to the heater core but I watched over 2 months ago so I don't remember. And if helps my cabin is always set to 69F ( not being high school boy, it just so happens 20.5C is 69F)

 

[kdryden99]

So I just rewatched, he doesn't mention a heat exchange but he mentions a chiller which I assumed was a heat exchanger. The battery and PTC heater run on the same loop according to Sandy's crew

 

[SnBGC]

If I remember correctly he showed the one linked to the heater core but I watched over 2 months ago so I don't remember. And if helps my cabin is always set to 69F ( not being high school boy, it just so happens 20.5C is 69F)

I watched one of the videos. He shows the chiller and the heater core.
They also show the cabin cooler heater which does NOT appear to be a PTC heater. It looks exactly like a TFE (Thick Film Element) type. This is the same type of coolant heater that is used in many Ford vehicles already (such as diesel powered vehicles). Looks like a dual plate type to me.

Probably a BorgWarner unit.

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