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Discussion Starter · #1 · (Edited)
2014 Volt owner here. Car won't produce any heat [Edit: on electric power]. I've been reading up in the forums and it seems that heat issues are a common problem for 2013-2014 models. I can't quite glean what the diagnostic flowchart looks like.

I put the climate on comfort and set it to 75 degrees (it's in the forties) and auto and cold air is blowing out the vents. I wait a while. It shows it's only pulling like 1 kw from the car (should be something like 3-4 kw, right?).

The coolant is a below the fill line so I plan on topping that up, but I'm doubtful it'll fix the issue.

It seems like some people have pulled a fuse and replaced it; following an entertaining guy on YouTube, I pulled #37 under the hood for a minute or two and put it back. It didn't look burned out. Didn't help, still no heat. (It didn't work for YouTube guy ,either).

Can anyone suggest where to get started on diagnosing the issue?
 

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Check the fuse, replace if blown. Don't know where fuses are? Get that hunk of bound paper called an Owner's Manual out of your glovebox and look under Fuses.
 

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Discussion Starter · #3 ·
Check the fuse, replace if blown. Don't know where fuses are? Get that hunk of bound paper called an Owner's Manual out of your glovebox and look under Fuses.
I pulled #37 (Cabin Heater Control Module) and replaced it, but no luck. Still no heat.
 

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You might find something here:
 

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Discussion Starter · #5 ·
You might find something here:
That is super interesting. Also it's more detailed than what I can use, like for an engineer rather than a DIY mechanic. It doesn't have a troubleshooting / diagnostics section.
 

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Use the "Search Community" bar to look for 'No Heat". This has been covered in the past. Please share which coolant tank is low, there are three separate circuits. Observation of only 1kw draw when heat is requested suggests the Heater Control Module not functioning properly, but low coolant, or air in coolant could prevent this heater from firing up.
 

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I had that 3-4 years ago. They replaced the heater core to fix the problem.
 

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Discussion Starter · #9 ·
Use the "Search Community" bar to look for 'No Heat". This has been covered in the past. Please share which coolant tank is low, there are three separate circuits. Observation of only 1kw draw when heat is requested suggests the Heater Control Module not functioning properly, but low coolant, or air in coolant could prevent this heater from firing up.
I was referring to the engine coolant container, which is apparently also the one that's used for cabin heat. I topped it up with some Dex Cool 50:50 premix but the heat is still not working. I did note some gurgling noises in the first minute or so but I don't know if that's anything more than normal. It also looks like the kw draw is elevated briefly during this time as well, so maybe the heater is beginning to fire up but then it turns itself off when it's unable to work properly, not sure.
 

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Discussion Starter · #11 ·
Are you saying that you're not getting any heat even in Hold mode with the ICE running for a few minutes?

No heat in EV mode has been a common problem. see here: No Heat in Electric Mode - Heater Pump Replacement - DIY?

No heat in EV and Hold is less common, but this guy had it: Heater not working in gas or EV mode
The guy with the less common no heat in EV and Hold said he needed a new heater coolant control valve and filter. Another user in this thread mentioned he needed a new heater core. Either way, looks like it'll need some work if I want heat. Drat.
 

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If you see the heat symbol on the climate screen and notice a 3-5 kw draw on the Driver Information Screen for 10+ seconds, the likely fix is the "Aux Heater Pump". This pump lives on the RF cradle directly behind the wheel. The plastic fender well must be removed to access. The pump is about $200, the Heater Module about $800. Labour could be 1-3x parts cost. Very DIYable. Check this forum for UTube videos. Proper coolant MUST be used! Special DexCool premix for GM electrics/hybrids, its electrically isolating.
 

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Discussion Starter · #13 · (Edited)
If you see the heat symbol on the climate screen and notice a 3-5 kw draw on the Driver Information Screen for 10+ seconds, the likely fix is the "Aux Heater Pump". This pump lives on the RF cradle directly behind the wheel. The plastic fender well must be removed to access. The pump is about $200, the Heater Module about $800. Labour could be 1-3x parts cost. Very DIYable. Check this forum for UTube videos. Proper coolant MUST be used! Special DexCool premix for GM electrics/hybrids, its electrically isolating.
What's the heat symbol look like? I don't notice one, but the car's still pretty new to me.
Also, I read the manual and all it says is DexCool coolant 50:50; sure now that I re-read it I see it mentioned deionized water, but they could've stressed that bit since most coolant is diluted with distilled water. Naturally I already topped up with O'Reilly branded Dex Cool premix, so I doubt it's the right one. Crap, I guess I need to get it flushed and refilled now.
 

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No immediate worries, if you only put a cupful in, likely no biggie, just have it changed out a bit sooner than you would otherwise. That Heater Module is in the engine coolant loop and is powered by high voltage from the propulsion pack and could trip an isolation fault, which will eventually shut you down. When the engine runs, this heater is closed off by the 3-way valve and lets the engine water pump supply warm coolant to the heater core. Your doin ok if its just the 'aux heater pump' - a known failure point...the pump spins and makes noise, but its magnetically driven impeller dosen't as its adhesive has failed. So if your handy, you could fix this with 25 cents of waterproof adhesive. (impeller must be mounted perfectly centered on its shaft as it spins at high RPM) As knowledge increases, fear subsides.
 

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Discussion Starter · #15 ·
No immediate worries, if you only put a cupful in, likely no biggie, just have it changed out a bit sooner than you would otherwise. That Heater Module is in the engine coolant loop and is powered by high voltage from the propulsion pack and could trip an isolation fault, which will eventually shut you down. When the engine runs, this heater is closed off by the 3-way valve and lets the engine water pump supply warm coolant to the heater core. Your doin ok if its just the 'aux heater pump' - a known failure point...the pump spins and makes noise, but its magnetically driven impeller dosen't as its adhesive has failed. So if your handy, you could fix this with 25 cents of waterproof adhesive. (impeller must be mounted perfectly centered on its shaft as it spins at high RPM) As knowledge increases, fear subsides.
Where am I supposed to see this indicator that the heat is running for the first 10 seconds? I am not sure what I"m looking for. Even watched this entertaining YouTube video of this guy driving around with his heater on showing the climate screen. His heat was working but I didn't see the heat symbol mentioned.
 

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2014 Volt owner here. Car won't produce any heat. I've been reading up in the forums and it seems that heat issues are a common problem for 2013-2014 models. I can't quite glean what the diagnostic flowchart looks like.

I put the climate on comfort and set it to 75 degrees (it's in the forties) and auto and cold air is blowing out the vents. I wait a while. It shows it's only pulling like 1 kw from the car (should be something like 3-4 kw, right?).

The coolant is a below the fill line so I plan on topping that up, but I'm doubtful it'll fix the issue.

It seems like some people have pulled a fuse and replaced it; following an entertaining guy on YouTube, I pulled #37 under the hood for a minute or two and put it back. It didn't look burned out. Didn't help, still no heat. (It didn't work for YouTube guy ,either).

Can anyone suggest where to get started on diagnosing the issue?
 

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Oof. Do you remember how much that cost you?
I had a service contract (extended warranty) which covered it. As much as I love the Volt, I had enough mostly non Voltetc related issues to more than pay for the warranty. Heater core, display screen, radio unit, windshield washer nozzles, drive motor rotor bearing and a module reprogram to fix “Service High Voltage Charging System” message.

Looking it up, it looks like they also replaced the heater water shutoff valve when they replaced the heater core. They might have tried that first before doing the heater core, I can’t remember.
 

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Where am I supposed to see this indicator that the heat is running for the first 10 seconds? I am not sure what I"m looking for. Even watched this entertaining YouTube video of this guy driving around with his heater on showing the climate screen. His heat was working but I didn't see the heat symbol mentioned.
It‘s on the bottom of the infotainment screen when you have climate controls selected. From the owner’s manual:
Rectangle Font Parallel Screenshot Number
Rectangle Font Parallel Screenshot Number
 

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Discussion Starter · #19 ·
Are you saying that you're not getting any heat even in Hold mode with the ICE running for a few minutes?

No heat in EV mode has been a common problem. see here: No Heat in Electric Mode - Heater Pump Replacement - DIY?

No heat in EV and Hold is less common, but this guy had it: Heater not working in gas or EV mode

OK thanks so much for this. I tried again to get heat in ICE (via Hold) mode. This time waited a while longer and the heat did begin to work! So yeah it's just No Heat in Electric Mode afterall.
 

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Discussion Starter · #20 ·
No immediate worries, if you only put a cupful in, likely no biggie, just have it changed out a bit sooner than you would otherwise. That Heater Module is in the engine coolant loop and is powered by high voltage from the propulsion pack and could trip an isolation fault, which will eventually shut you down. When the engine runs, this heater is closed off by the 3-way valve and lets the engine water pump supply warm coolant to the heater core. Your doin ok if its just the 'aux heater pump' - a known failure point...the pump spins and makes noise, but its magnetically driven impeller dosen't as its adhesive has failed. So if your handy, you could fix this with 25 cents of waterproof adhesive. (impeller must be mounted perfectly centered on its shaft as it spins at high RPM) As knowledge increases, fear subsides.
So I'm not more confident it's the pump. It seems so reasonable to just apply more adhesive to get the existing pump working again. I could not find any instructions or YouTube videos for this; do you know of one? Have you done this yourself? Pretty awesome to keep old parts still working when possible.
 
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