No heat in my 2015 Spark EV

[Porsche]

I did a quick search in the forum and couldn't find anything, but I think the cabin heat has stopped working in my 2015. When I turn up the temperature, once I get near the max, I can hear a change in the sound of the incoming air, suggesting that the air is rerouted at some point, but no heat at all. Also, no increase in power drain. Is there a heater fuse or something? Some setting I may be missing? I've tested the heat a few weeks ago and it seemed to be working. I mostly don't change the climate controls at all, usually set manually for minimum temperature, low fan, no AC. I will mention that I did set the controls to full "AUTO" then reset everything manually again, before having this problem. I guess a trip to the dealer may be in order, but I'd appreciate any input if it might be just a fuse or a setting that I've missed. Thanks all for any suggestions.

 

[ElDobro]

Turn on the settings for heat, then pop the hood. Facing the car, the coolant reservoir for the heater is all the way to your right. If the heat is running, you should hear the pump and see the coolant moving in the reservoir. Now, the coolant heater is the black box, with a warning sticker on the top of it, to the left of the brake reservoir. If the heater is working, you can put your hand on it and feel it getting warm. See if both of these are working. If not, then look for a fuse.

 

[Infinion]

In case you wanted to explore the possibility of a blown fuse, this is the connection diagram for the cabin heater.

As you can see, the heating element runs off the high voltage pack and there are two low voltage fuses that you can check under the hood.
I'll include all the relevant info for you.

 

[Porsche]

Wow, thanks. At the risk of missing the obvious, I assume the fuses would be the #4 CHCM Fuse (Coolant Heater Control Module) and the #12 Auxiliary Heater Pump Fuse? They're not explicitly labeled on the schematic.

Also, I'm curious; pumps? coolant? I know the Spark uses a resistive heater, but is there an intermediate heat transfer to a circulating liquid first?

 

[ElDobro]

Yep, the resistance heater heats up the coolant that is then circulated through the heater core by an electric pump. There are three separate coolant circuits, one for the battery, one for the electronics and the third for interior heat.

 

[Infinion]

Wow, thanks. At the risk of missing the obvious, I assume the fuses would be the #4 CHCM Fuse (Coolant Heater Control Module) and the #12 Auxiliary Heater Pump Fuse? They're not explicitly labeled on the schematic.

Also, I'm curious; pumps? coolant? I know the Spark uses a resistive heater, but is there an intermediate heat transfer to a circulating liquid first?

I looked at it and I agree it's not completely explicit. However, you are absolutely correct in your deduction!

I dug a bit further, because I'm not happy with the ambiguity of the previous tables and found some more descriptive ones that should provide absolute clarity:
As you can see below, the following table shows the label, assigned name, and description of each device as well as fuse rating.
If you look at the earlier schematic in the previous post, the Coolant Heater Control Module (K10) and Auxiliary Heater Control Pump (G36) have assigned names "F10UA" and "F5UA" listed respectively in the table along with a short description. This wasn't correlated in the previous tables found in the user manual, but instead, these names are correlated in the following images of the fuse block, in both an abstract label view and a more literal top view. This is unfortunately the only resolution I have, if you're able, try to view the image and zoom in.

I'll include the other tables for completion

Match the label name in the table with the label view of the fuse block, or match the device name (F5UA) with the drawing view's F# (F5)

If you have access to a fuse tester, or if you can visually inspect the fuses for a break and find that it is indeed blown, before replacing the fuse I would investigate why the fuse was blown in the first place. For example, If a pump has seized, it would draw stall current for too long, which could blow its fuse. I don't know if this would become obvious through a noise or some other indication, but you could make certain of the nature of the failure with an OBD II reader.

It's your choice how much caution you wish to execute, but if you do pull a code let me know and I can look it up in the service manual for you. If you do it at a chevy dealer they'll probably charge you $100 or more for it as they are want to do.

 

[Porsche]

OMG, Thanks again. I really must get a service manual. Someone was selling his on the forums, but never replied, probably already sold it. I did test both fuses and they are OK. I'll try a few more things (see if I can find my cheap OBDII scanner), but will probably end up at the dealer anyway.

 

[ElDobro]

If the heater system under the hood is working and the blower motor operates at all speeds, it could be the temperature door actuator under the dash. If the door is in the cold position and doesn't move to the heat position, you won't get any heat, even though everything else is working.

 

[Porsche]

If the heater system under the hood is working and the blower motor operates at all speeds, it could be the temperature door actuator under the dash. If the door is in the cold position and doesn't move to the heat position, you won't get any heat, even though everything else is working.

I didn't really check the heater system under the hood, but the blower motor does operate normally at all speeds. Also, as I increase the temperature setting, I hear a distinct change in the sound of the rushing air. And last, if I set the heat to full maximum, I get no change in power consumption. Before, when the heat worked, I'd get, I don't know, maybe 2kW with full heat while standing still. Now, it's zero. I suspect that #2 and #3 strongly suggest that it's not the door actuator, but the actual heat generation.

 

[ElDobro]

If the heater system under the hood is working and the blower motor operates at all speeds, it could be the temperature door actuator under the dash. If the door is in the cold position and doesn't move to the heat position, you won't get any heat, even though everything else is working.

I didn't really check the heater system under the hood, but the blower motor does operate normally at all speeds. Also, as I increase the temperature setting, I hear a distinct change in the sound of the rushing air. And last, if I set the heat to full maximum, I get no change in power consumption. Before, when the heat worked, I'd get, I don't know, maybe 2kW with full heat while standing still. Now, it's zero. I suspect that #2 and #3 strongly suggest that it's not the door actuator, but the actual heat generation.

It takes about 5 minutes to see if the pump and heater under the hood are working. You can hear the pump and to can touch the heater to see if it's getting hot. If they're not working, then it's time to see the dealer 'cause it may be a sensor or the controls.

 

[Porsche]

First, thanks all, for all the wonderful, detailed information and great suggestions. I did check, and no, the heat was never coming on at all, so, off to the dealer. Now, here's the part where I embarrassingly get to share with all of you what an idiot I am. (ever notice how the first thing listed in the troubleshooting section of a consumer appliance user manual is "make sure it's plugged in"?)

So, in every ICE car, waste heat from the heater core is mixed with cold air. The temperature control simply adjusts the mixture of hot and cold air. Want air conditioning? Just push the button and the AC compressor turns on, along with a nice LED. So, the guy from Chevy calls and tells me the heat works just fine, explaining to me that you just have to push "the little button". I think about it and say, "no, that can't be right. I'm not stupid. I tried that. I know that you should turn off the AC when you want heat. There's no heat at all!" Sure enough, when I get there, the heat is working just fine. I just slipped a mental gear, forgetting that you have to turn the "TEMP" button ON, not OFF, to get BOTH heat and AC. No, unlike my ICE car, the temp button doesn't just turn on the compressor. It turns on the entire temperature control system. The car will turn on heat or AC based on the actual vs desired temperature.

So, all along, I was turning the heat OFF when I thought I was turning just the AC off. Not sure what I was thinking. I have used the heat before and did know this. So, problem solved.

On another note (which I will also add to the relevant post elsewhere), while the car was at the dealer, I had them perform service bulletin PI1382A. There's an ABB DC fast charger near me that just wouldn't charge the Spark. Just gave a communications error. Now, after the service bulletin, it charges reliably there. For those interested, see:

https://static.nhtsa.gov/odi/tsbs/2016/MC-10138002-9999.pdf

 

[ElDobro]

Sometimes, it's just the little things.