Electric Aux Heater retrofit

Your build sticker is very similar to my one. Your car has the 140A alternator and also 1500W electric aux heater fitted from the factory.
What option code indicates the 1500w heater? Thought 7E4-7E8 indicated additional heater?
 
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Check you have "B"

Believe the wiring from the heater can be seen behind the glovebox...
 
7E4 7E8 is WEBASTO. No actual code for electric, but as long as car has the not hot country code 8Z5 then the electric heater is fitted.
OK I'll start stripping covers off to double check. Do you know if you can access the control unit for it via vcds?
 
I have never checked VCDS for the electric aux heater, I know the Webasto is there. All I suggest is have a good look around the bottom of the heater box to see if any cables come out almost at the bottom and face forward towards the engine.
It looks like the ~"sump" of the heater box is only secured by clips, if you can drop that the heater element should be right there...


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OK I'll start stripping covers off to double check. Do you know if you can access the control unit for it via vcds?

I have never checked VCDS for the electric aux heater, I know the Webasto is there. All I suggest is have a good look around the bottom of the heater box to see if any cables come out almost at the bottom and face forward towards the engine.
It looks like the ~"sump" of the heater box is only secured by clips, if you can drop that the heater element should be right there...


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What option code indicates the 1500w heater? Thought 7E4-7E8 indicated additional heater?
My car with the electric heater doesn't have any 7Ex codes on the build sticker either. I thought I had a file on my computer with the Webasto car build codes assuming this may have one but I can't find it at the moment.
 
Looks like I have got an electric heater. Now the challenge is to find out why it's not working.
Thanks Steve
 

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Looks like I have got an electric heater. Now the challenge is to find out why it's not working.
Thanks Steve
What condition is your battery in? I know mine hasn't been tip top recently so I was wondering if the lack of electric heater was due to load shedding bearing in mind I'll have had rear defrost / mirrors, lights etc., on at the same time.
 
What condition is your battery in? I know mine hasn't been tip top recently so I was wondering if the lack of electric heater was due to load shedding bearing in mind I'll have had rear defrost / mirrors, lights etc., on at the same time.
My bosch battery is approx 3years old. I'm earlies this week, so when cold will try car without anything else turned on on start up and try heater operation
 
However the 5kw also has to heat the block.

The electric heater only does the interior.

Unless someone can tell me how the adjust the webasto start temperature. 5c is too low for me.
the electric heater heat the engine too it lays under the radiator in the cabin and heat it up so it heats the engine too
regards
 
Apologies for dragging up this thread a bit, but I have recently spent a lot of time looking at Aux heat options so I can hopefully clarify some things.
I see the 5 degrees figure mentioned in various places but it's an A2 urban myth :) The Webasto start is 7.5 degrees C. I believe that once the engine is up to either 70 or 80 degrees and the cabin is up to temperature, it will turn off again if the outside temperature is above 5 degrees. Otherwise it stays on.
It may vary somewhat on the car. From a random ECU file I found on the internet for a 1.4 TDI, it is actually 4.6 degrees C for the "on" time, and 6.6 degrees C for the off time. So anything below 4.6 means the Webasto can be on, assuming other conditions are met, and the heater will remain on until the temperature reaches 6.6. The Webasto iteself has no awareness of the cabin temperature (I don't think), although it may indirectly get switched off by the Climate controls (cannot verifiy as I don't have access to the code). For that file, the coolant temperature based cut-off is 79 degrees and the cut-in is degrees.
 
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Have climate control and also vcds when i looked at it found this
group 16 aux heating generator load 34.8% auxillary heating shut off condition 01000000 heating element activation 00
supply voltage terminal 30
Couldn't access the additional heating unit?
If that's from VCDS I think that is Least Significant Bit First (LSB), so Bit 6 of the shut off condition is set. Meaning the heater is off because the climate control is telling it to be off.
 
However the 5kw also has to heat the block.

The electric heater only does the interior.

Unless someone can tell me how the adjust the webasto start temperature. 5c is too low for me.
You can adjust it to an extent. As in my previous post there is information in the form of an ECU map that defines switch on/off conditions for various things. However the "executive" switch is the driver via the climate control. So even if you raise the maximum switch on temperature in the ECU, there will most likely be another temperature limit in the Climate control that will intervene. This cannot be easily changed without reverse engineering the climate control software. (Anecdotally around 10 degrees C but can't confirm). If some has the ability and is comfortable reading and loading flash files I can adjust it higher for you.

As an alternative, the ECU can also be configured to activate the Webasto and PTC regardless of climate control setting, but just when the outside temperature or coolant temperature is low. It can also be configured to activate the the aux heaters with a switch input too if you wanted that.
 
Hi. Thx for the info. I need someone with a lot more time on their hands than me to look at this issue. With everything I have going on, I'm sad to say the A2 has taken 2nd place at mo. It is going to be pampered tho with new cast front arms and hopefully a new 12mth ticket(mot). Before the end of this month.
Steve
 
HI All
I have just purchased a current clamp meter that measures dc current usage.
Now the temperature in south wales is currently Bloody Freezing i will place the clamp meter on the cable to the electric heater and see if it's working.
Need heat with leather seats and cold weather.
Thanks
 
HI All
I have just purchased a current clamp meter that measures dc current usage.
Now the temperature in south wales is currently Foooking Freezing i will place the clamp meter on the cable to the electric heater and see if it's working.
Need heat with leather seats and cold weather.
Thanks
Check Engine Group 016 to see if the engine is happy for it to run.
See here:
Post in thread 'Webasto! Why won’t it work on its own…. VCDS enabled??' https://www.a2oc.net/community/inde...rk-on-its-own…-vcds-enabled.54171/post-546118
Mac.
 
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