Short answer: An auxiliary heater (Zuheizer) only runs while the engine is running and helps the engine and cabin warm up faster. A parking heater (Standheizung) also heats with the engine switched off, via timer or remote control. In the VW T5 both are usually a Webasto Thermo Top C – you can tell them apart by the part number: …815071… stands for the auxiliary heater, …819008… for the parking heater.
Many T5 owners assume their van has a parking heater because there is a Webasto unit in the engine bay. Often, however, it is "only" an auxiliary heater. The difference matters for troubleshooting and above all when ordering a replacement: auxiliary and parking heaters look almost identical but are not simply interchangeable.
What is the difference between an auxiliary heater and a parking heater?
Auxiliary heater: Modern diesel engines produce little waste heat. To make sure the engine and cabin still warm up quickly in winter, the auxiliary heater switches on automatically at low temperatures – but only while the engine is running. It cannot be operated manually.
Parking heater: It heats the coolant, and with it the engine and cabin, even when the vehicle is parked. It is started via timer, remote control or app. Many parking heaters also take over the auxiliary heater function while the engine is running.
How to tell what is fitted in your T5
The most reliable indicator is the VW part number on the heater's type plate:
- Auxiliary heater: part numbers following the pattern 7H0 815 071 … or 7E0 815 071 … (e.g. 7H0815071G, 7E0815071A)
- Parking heater: part numbers following the pattern 7H0 819 008 … or 7E0 819 008 … (e.g. 7H0819008T)
Further clues: Is there a remote control, a timer button or a "parking heater" menu in the climate control? Then it is very likely a parking heater. If none of these exist, it is usually an auxiliary heater.
If you are unsure, simply send us a photo of the type plate.
Can an auxiliary heater be swapped for a parking heater?
Not just by plugging it in. Parking heaters need additional controls, matching coding and sometimes different wiring. When ordering a replacement, therefore, always choose the same unit that was fitted before – i.e. with the same part number or an approved successor number. Diesel and petrol versions are not interchangeable either.
Typical signs of a fault
- The heating takes noticeably longer to warm up in winter than usual
- The parking heater starts but switches off again after a short time
- White smoke or a smell of diesel from the heater's exhaust
- Fault entries in the engine or heater control unit, e.g. flame failure, glow plug or combustion air fan
- The heater no longer responds at all
Repair or exchange unit?
Repair of your own unit: You remove the heater and send it to us. We test it, repair it and return your own unit. Repairing a VW Thermo Top C costs a fixed price of €300.
Reconditioned exchange unit: For the T5, reconditioned auxiliary and parking heaters are available on an exchange basis from €399. Select the variant with your part number. With a deposit (€200) you receive the exchange unit in advance and send your old unit back afterwards – the deposit is refunded after inspection.
Both come with a 12-month warranty. Shipping is free within Germany and costs €25 to other EU countries.
Frequently asked questions
My T5 has an auxiliary heater. Can I turn it into a parking heater?
Retrofitting is possible in principle, but it involves more than the heater itself: controls, coding and possibly wiring. This should be planned by a specialist workshop.
Will the unit from a T6 or Multivan fit?
That depends solely on the part number. The same part number means a matching unit – regardless of the model name.
I can't find a part number. What now?
Send us a photo of the heater or call us on +49 5671 7664710. We will help you identify it.
Straight to the right unit: VW T5 Thermo Top C diesel auxiliary heater, exchange · VW T5 Thermo Top C diesel parking heater, exchange · VW Thermo Top C repair
