Do I have an auxiliary heater ?

[Crasher]

Just wait until these PTC (Positive Temperature Coefficient) heaters used on electric cars start going wrong

[VAG-Abound]

Just wait until these PTC (Positive Temperature Coefficient) heaters used on electric cars start going wrong

Isnt yhat the right way around for safety? On a fridge open circuit on the sensor looks like very cold to an NTC device, so the compressor turns off. On a heating circuit open circuit om PTC looks like very hot, so element is disconnected. Failsafe im both cases.

Or am I misunderstanding the point?

[Crasher]

No, it is the cost...£700 plus labour.

[SR123]

1K0963235 E were the rubbish ones. Not sure what year they went too.

Have you replaced them before?
Mine is throwing up error codes and the hardware id matches the part number you've quoted. I've seen the youtube clip showing the small resistors that go open circuit. Doesn't look too tricky to resolder.
I took out the glove box on my Golf mk5 but couldn't see the aux heater anywhere - where exactly is it please?

[jonathanfenton]

Swapped mine several time for “known working” ones which weren’t tested just taken out of cars and sold on eBay. You have to take your Centre console out to get to it. I’ve been so tempted to cut it as you only need about 6 inches from the end of the console, instead you have to take climate panel out, the two knee rest things, gear stick gayer and rear ash tray out to get to all the bolts. Watch for the console ripping your handbrake leather, I got away with it but seen others make a right mess.

[SR123]

Thanks. I was looking in eBay but the ones I've seen aren't tested. Is there a quick way to check whether an aux heater will work without installing it in your car first? Is it as simple as connecting up 12v and earth to it and see if it heats up?

[jonathanfenton]

Im afraid not. You need to plug it in and meet the correct conditions for it to start, using VCDS to run a test is futile as even when it’s faulty the test will heat it up any elements that still work but will stop it working in normal conditions. You can plug it in and check for codes before screwing it in but you’re only saving a few mins. The hour or so strip down is the only way to go without a bench setup which none of us has.

It will detect a faulty element and then shut the whole unit down. I stripped one down and went to reheat some components on the board but as soon as I touched a resister with my tiny gas iron the resister flew across the garage so I haven’t tried to repair one again. I’ve seen some people claiming to have repaired them. I’m clearly not an electronics expert and I failed miserably. Having run without it for a few winters now it does take longer to heat up but not massively. The only real disadvantage I’ve found is if you naughtily start the car to defrost whilst you make your brew in a morning the cars not even lukewarm after 10 mins.

I’ve decided to just live with it broken as I’ve spent about 8 hours trying to fix it with about 6 used units. It clearly wants to stay broken. The fact the newer units don’t have a pcb glued onto the end of elements proves what a stupid design it was!

[SR123]

Very insightful, thanks. So basically, any eBay 'pre-owned' purchase is going to be pot luck!
I've got a friend who's an electronics whizz kid with a multitude of different types of soldering irons, I'll set him to work on mine and see! I'm thinking I'll try once to get it working before living without it, but having the fault code still there to remind me I failed!

[VAG-Abound]

1K0963235 E were the rubbish ones. Not sure what year they went too.

Were you saying above the heater and controller became separate items, or did that mean single unit but detachable controller?

Looks like 1K0963235F was fitted to various vehicles from Nov 2006 or post a face-lift: A3, TT, Caddy, Golf, Passat, Jetta, Scirroco, Sharan, Tiguan

Then a G suffix from ~2011.

[jonathanfenton]

They stopped using an integral controller altogether, the newer units became “dumb” and just used a relay from the convenience unit. I guess they applied the kiss method on them. Keep it simple stupid.