He there, I started my car this morning (outside temp was around -15℃). I got strong burning smell after setting a/c to max. Later this day i have checked it with mechanic. You can see what happened from the attached pictures. This is 2018 Octavia, this shouldn't have place.

Edited 13 January, 20242 yr by Dean

I suspect a loose connection on the supply tag has caused that overheating and failure. Looks to be a high current supply.  

Do you have the auxiliary heater?

12 hours ago, T07 said:

Do you have the auxiliary heater?

No I don't.

Fair enough. Thought it was maybe the aux heater. Not sure what else is drawing current down there 

 

https://forums.tdiclub.com/index.php?threads/burning-smell-from-heat.513304/

9 minutes ago, T07 said:

Fair enough. Thought it was maybe the aux heater. Not sure what else is drawing current down there 

 

https://forums.tdiclub.com/index.php?threads/burning-smell-from-heat.513304/

Sorry i'm not a mechanic. The part looks like this

16 minutes ago, T07 said:

Fair enough. Thought it was maybe the aux heater. Not sure what else is drawing current down there 

 

https://forums.tdiclub.com/index.php?threads/burning-smell-from-heat.513304/

It is a supplementary heat booster which uses a large resistor to create cabin heat. 

 

The auxiliary heater is a webasto coolant heater located in the engine bay to pre heat the engine and cabin.

 

 

 

Regarding your fault, id be checking the condition of whats left of the terminal for a loose connection, and also check the heater resistor for a short circuit which would also cause this. 

Edited 13 January, 20242 yr by ApertureS

13 hours ago, T07 said:

Do you have the auxiliary heater?

Good question. You were right.

On 12/01/2024 at 20:29, jac3kfire said:

He there, I started my car this morning (outside temp was around -15℃). I got strong burning smell after setting a/c to max. Later this day i have checked it with mechanic. You can see what happened from the attached pictures. This is 2018 Octavia, this shouldn't have place.

I have same problem now,what you did with that burned cable?or you just changed that heater and thats it?

I left it disconnected and took out the fuse.

1 hour ago, jac3kfire said:

I left it disconnected and took out the fuse.

So you not fixed ?

 

33 minutes ago, Robertinskis said:

So you not fixed ?

 

Yes. Its still broken. Not only the heater but cable has to be replaced.

2 hours ago, jac3kfire said:

I left it disconnected and took out the fuse.

I have to wonder what sort of fuse allows the cable to melt like that without opening the circuit itself. 😲

Check the fuse for the correct rating.

I don't think I'd trust that fuse again. One for the bin, IMO.

Any high current circuit will overheat like that if a connection is not tight without blowing a fuse, the current drawn is actually less due to the extra resistance of the loose connection.

 

Loose connections are the cause of most electrical fires, short circuits are relatively safe events if the circuit is fuse protected.

 

The cable hasn't melted through carrying too much current, were that the case it would have melted throughout its whole length, it is conducted heat from the resistance (and arcing at higher voltages) at the loose connection

Edited 13 December, 20241 yr by J.R.

1 minute ago, J.R. said:

Any high current circuit will overheat like that if a connection is not tight without blowing a fuse, the current drawn is actually less due to the extra resistance of the loose connection.

 

Loose connections are the cause of most electrical fires, short circuits are relatively safe events if the circuit is fuse protected.

Where can i find that fuse octavia. 2018

18 hours ago, Robertinskis said:

Where can i find that fuse octavia. 2018

 

On 13/12/2024 at 17:51, jac3kfire said:

I left it disconnected and took out the fuse.

Hi jac3kfire,

I think I've got the same issue which started last week when the temperature significantly dropped. The nearby garage coudn't find it the problem.

Where abouts this heat booster is located please? I think I need to get my tools and start digging :D