2018 Leaf - no heat, no range indicator

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hutchR

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Joined
Dec 30, 2023
Messages
9
I tried searching for solutions to these issues, but came up empty handed.

My 18 SV sat in the driveway for a week, fully charged before I went out this morning. After driving for about 20mins I had no heat, just cold air. Normally when it's cold out, I can hear the heat pump kick on, but not this time. All I can hear is the fan.
I also noticed the range indicator is no longer showing in the dash cluster.

I'm trying to avoid taking it to the dealer for a diagnosis as I much rather fix it myself.

Any idea as to the problem and potential solution?
 
It's an odd combination. The resistive heater (aka PTC) should have taken over if the heat pump failed. What was the ambient temperature that morning? Because if the PTC failed and it was well below Freezing out, then the heat pump wouldn't do much. I suspect that a low 12 volt battery is possibly, somehow behind this, but I'm not sure of the mechanism...
 
LeftieBiker said:
It's an odd combination. The resistive heater (aka PTC) should have taken over if the heat pump failed. What was the ambient temperature that morning? Because if the PTC failed and it was well below Freezing out, then the heat pump wouldn't do much. I suspect that a low 12 volt battery is possibly, somehow behind this, but I'm not sure of the mechanism...
Click to expand...

It was about -1C this morning.
I did check the battery as I realize its 5yrs old now, but it was still showing 12v.
 
12.what volts? If 12.0 or 12.1 volts, don't rule out a dying accessory battery. You want 12.25 or higher. Also, was the air blowing from the vents chilly but warmer than the cabin air, or as cold as the air outside? That would be the difference between a functioning heat pump and a non-functioning heat pump.
 
LeftieBiker said:
12.what volts? If 12.0 or 12.1 volts, don't rule out a dying accessory battery. You want 12.25 or higher. Also, was the air blowing from the vents chilly but warmer than the cabin air, or as cold as the air outside? That would be the difference between a functioning heat pump and a non-functioning heat pump.
Click to expand...

The air was cold like the outside air.
 
I live in coastal Texas, so 40-50F is a cold morning. But I'm stunned out how quickly the car starts putting out warm air when I get in it.
It's almost immediately, and the Energy Consumption screen doesn't show much of a drain, to be honest.

I guess I don't really understand what a heat pump actually is, but I'm impressed. I'd definitely be looking to get it fixed if it stopped working like it currently does.
 
hutchR said:
I tried searching for solutions to these issues, but came up empty handed.

My 18 SV sat in the driveway for a week, fully charged before I went out this morning. After driving for about 20mins I had no heat, just cold air. Normally when it's cold out, I can hear the heat pump kick on, but not this time. All I can hear is the fan.
I also noticed the range indicator is no longer showing in the dash cluster.

I'm trying to avoid taking it to the dealer for a diagnosis as I much rather fix it myself.

Any idea as to the problem and potential solution?
Click to expand...
You definately need to replace the 12 volt battery. I just replaced mine on a 2018 Leaf and then found the heat and air-con buttons didn't work. However the auto button worked and this had a knock-on effect of making the the heat and air-con buttons work.
 
The leaf doesn't like being ignored. I had my power assisted breaking quit after sitting for two weeks. After letting it idle for a couple hours, I believed it recharged the 12v battery enough to work properly. Yours may be on the way out. Also remember that there's an issue with the fan on high that shuts off the heater. Best to turn down the blower a notch until it warms up.
 
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Do you not get a warning on the dash when the 12V battery is about to die? I do for the key fob batteries - just assumed I would for the 12V.
 
I did check the resting battery voltage this morning and it was 11.7volts, so its time to replace it.

I'll grab a new battery today and see if that fixes the problem.
 
Snakebitten said:
I guess I don't really understand what a heat pump actually is, but I'm impressed. I'd definitely be looking to get it fixed if it stopped working like it currently does.
Click to expand...
A heat pump works just like an air conditioner, but the coils are reversed. An air conditioner absorbs heat on the evaporator coil (one in the passenger compartment) and releases it at the condenser (in the front of the car). A heat pump just switches what the coils are used for, so the one in the car gets hot and the one out front absorbs the heat in the air. Heat pumps most often can be reversed to act as A/C as well.
This is why you don't need the car to "warm up the engine" before you get heat, it starts right away and uses the heat in the outside air to warm up the inside.
They work best above freezing. In high humidity and low temps, the heating drops off.
 
Hmm, your 2018 should have a PTC heater as well as a heat pump. I had this same issue with my 2015 SV and the heat pump just blew cold air when it was below freezing. The PTC heater supplies heat when it's too cold for just the heat pump. Below freezing the heat pump isn't going to give you much more than cold air. However, if the PTC heater isn't working then you may have a bigger issue. I seem to remember this issue being discussed several years ago. From what I remember the PTC heater is powered from its own high voltage feed from inside the battery where (unfortunately) it's also fused. Sometimes when the PTC heater fails it will short or present a low enough resistance to blow the fuse inside the high voltage battery shell. This is what I remember being discussed. Might want to check the voltage at the PTC heater element under the dash. Be careful, it's nominally 400Vdc. If it's not present then it's likely the fuse inside the high voltage battery. There is a thread somewhere on this forum and I think there are discussions about this on YouTube. I think there were even suggested work arounds for those who didn't want to drop and open the HV battery shell.
 
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TronJockey said:
Hmm, your 2018 should have a PTC heater as well as a heat pump. I had this same issue with my 2015 SV and the heat pump just blew cold air when it was below freezing. The PTC heater supplies heat when it's too cold for the just the heat pump. Below freezing the heat pump isn't going to give you much more than cold air. However, if the PTC heater isn't working then you may have a bigger issue. I seem to remember this issue being discussed several years ago. From what I remember the PTC heater is powered from its own high voltage feed from inside the battery where (unfortunately) it's also fused. Sometimes when the PTC heater fails it will short or present a low enough resistance to blow the fuse inside the high voltage battery shell. This is what I remember being discussed. Might want to check the voltage at the PTC heater element under the dash. Be careful, it's nominally 400Vdc. If it's not present then it's likely the fuse inside the high voltage battery. There is a thread somewhere on this forum and I think there are discussions about this on YouTube. I think there were even suggested work arounds for those who didn't want to drop and open the HV battery shell.
Click to expand...

I did a little reading up on this issue with the gen 1 Leafs. I checked the climate control energy usage on the touchscreen and with the heat at max, it showed zero energy usage. I would check the PTC voltage, however, if nothing is working and not drawing any power whatsoever, I feel confident that there is no power to the PTC. This does unfortunately seem like a PTC/fuse failure.
But what I still don't understand is why my range indicator is not showing.
 
Update. Nissan dealer showed a variety of error codes (b2631, b2777, b277b, b27c0, b27c1) that all said 'communication error' with various HVAC parts. They feel that the heat pump control unit is the problem.
 
Google those codes individually, you may have a bad PTC heater. 2777, 277b There are threads here about it, it happened at least to older 2013-2015 Leafs commonly. My 2014 was bad from the start, dealer always blew off my dad telling him that's how the heat 'works', wtf. It was way out of warranty when I took it over, I got one from a salvage car that has been working. It can be taken out via the glovebox area, there's a bracket that can be sacrificially bent out of the way and then bent back. I opened up the original bad one, thought oh maybe it'll work this time, oh no... it blew the pack precharge resistor next time I keyed up. doa! Then I fixed the precharge resistor, and got a new used PTC heater.

Here's a good thread about it.
https://mynissanleaf.com/threads/has-your-leafs-ptc-heater-failed-reply-here.28105/post-596029
 
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