[blix1988]

Hello is it possible to code in electric / PTC heater from diesel E90 to petrol E90? I have e91 N52.

In the past I added PTC to my V50 1.8i and it was awesome, but I had to pay a guy to docode and change the setting of Climate control.

[Andystobbs]

Doubt it has been done but might be possible. Provided the DME can transmit the signal of available alternator power onto the canbus.

[k90]

I just registered just to start this exact thread!


Not having PTC is just BS once you get used to having instant heat.
Diesel is rather cold for 20mins but at least PTC heating softens the frost on windscreen and blows instantly a hole to frost right above vent that assists scraping a great deal by providing a weak point.

Originally Posted by Andystobbs

Doubt it has been done but might be possible. Provided the DME can transmit the signal of available alternator power onto the canbus.

Same data is used by heated seats and rear window heating + mirrors?

How about the physical implementation?

There is red wire plugged into prod terminal of the PTC element.
Where is the other end and is it different to diesel model? Some fuse board or +12v busbar?

Also there is signaling connector connected to PTC. Bet that part of wiring harness is not just hanging there in gasoline model?

I assume relevant controllers are the same as difference is only signaling and power is clearly done in PTC itself.

[Runnin'Rich]

Wow that's cool, a while ago I was looking into a webasto heater that uses the fuel from the tank. But this is way simpler

[k90]

Originally Posted by Runnin'Rich

Wow that's cool, a while ago I was looking into a webasto heater that uses the fuel from the tank. But this is way simpler

By no means 12V PTC 180wattsorsomething is replacement for Webasto/Eber/Russian variations/Chinese variations that run in kilowatts of heating capacity. Or Defa/Kalix engine heater running from mains accompanied with interior 500-1400Watt PTC blower running from mains. It's just convenient 180W of heating directed right to the windscreen on-demand. It's basically just a slight breeze of warm air. But it's there - every time.

Those auxiliary heaters gradually build temperatures until it's toasty inside assuming the blower etc. is overriden by auxiliary heater. But heating up the block takes time. And interior wont heat up until block is warm. You can set timers etc. and some you can even press from remote controller, call from your cell or click from app to start heating. 15mins gives you a headstart getting to the operating temperatures, but wont blow ice off the windows. 45-60mins usually does the trick.

[k90]

While taking a look under the dash to prepaire for LDM installation I took a picture of the left side of HVAC box.

Has anyone removed and installed PTC with dash in place? I heard that heater cell can be lured out and new one in without removing dash but PTC is one step further back. By quick glance I would say it's blocked in there by what seems like an air duct or something. Not sure if visible in picture but plastic thing at right might be it / part of it.

Edit. the duct seems to have removable section. Not sure if it can be splitted in place. One end of it needs to give a bit in order to remove the duct section.

[k90]

^ reply to myself. It's LIN not CAN.

Originally Posted by Andystobbs

Doubt it has been done but might be possible. Provided the DME can transmit the signal of available alternator power onto the canbus.

Okay it's worse than this potentially.
IHKA needs a dedicated alternator signal from DME(it might pass through junction box or be directly connected from DME). I have yet to find documentation for the signal.
Not sure if the signal is connected in petrol models until I look at connector to IHKA if it has populated contact at position no. 10 in connector X608.
I could also maybe see if IHKA has continuity from input to output of this dedicated signal. If IHKA is just a pass-through for this signal in aspect of PTC function.

**Add
Power supply for the PTC needs to be routed from 100A fuse holder of rear fuse carrier sitting on the battery.

Signals from IHKA to PTC unit:

• Ground, Stepper motors
• Supply, Stepper motors
• Signal, electric auxiliary heater
• Signal, LIN bus, Stepper motors (connected paraller to first of the chain of stepper motors in LIN bus)

Question:
Is IHKA in/part of/right under the HVAC control panel / is IHKA the control panel?

[Andystobbs]

IHKA is the whole system, including the panel which does all of the management, the heater box including motors, sensors etc and any satellites like webasto, rear air distribution etc.

There are only 3 lines that go to the ptc from the IHKA panel. You are right about the available power signal, it isn't on the CANBUS. It is a single wire from DME to IHKA, passing through Junction box

[k90]

I need to correct earlier myself. PTC is 1250W max.

Forced IHKA control panel off and the wire from junction box to IHKA is populated even in petrol models, but it's likelly open ended. It's pin no.10. No voltage visible in multimeter or any modulation visible through noise in scope. Multimeter resistance measurement gives solid O.L. Most likelly ends at junction box. And it's not a suprise. MSV70 pinout doesn't have any pin that would suit.

Technical information gives a hint that the signal from diesel controller is pulse width modulated.
But doesn't give pinout or connector type

I don't think engine management needs to be involved in order to use
PTC in petrol car, but a microcontroller board living somewhere around junction box eavesdropping BSD bus wire. It's rather simple if alternator returns field%. Another option is more complex microcontroller board that retrives this information via canbus.

Some measurements from diesel could be useful such as PWM frequency, polarity, typical duty% @ idle, signal state ignition off, signal state ignition off - ihka rest, signal state ignition on - engine not running.

I should maybe check some diagrams for diesel controllers if there is symbols for output driver type but it seems the whole signal is missing from all diagrams so.. unlikelly to find anything.

[Andystobbs]

Here it is on 2010 e91 diesel

[k90]

Originally Posted by Andystobbs

Here it is on 2010 e91 diesel

Thanks!
I forgot to measure that IHKA pin10 to pin10. It clearly isn't just a pass through by this diagram, but a common collector output. Likelly it's just for having all PTC signals being powered from IHKA panel supply. Or to split circuit faults into 2 (DDE output and IHKA output) for easier diagnosis.

I assume at least the IHKA -> PTC is PWM.

Any Diesel Friends here with oscope, aptitude and eagerness to fiddle with wires to characterize the signal from DDE to IHKA?

[Andystobbs]

It is pwm. I have a picoscope but finding the time is another matter

Edit: the first picture below should be below the second one to make it read as per bmw intended.

[blackout_ssri]

I'm also very interested in this as I already have the hardware on my car. It's a 2008 330i with the whole AC/heating box thingy from a diesel.

I'll try this week maybe to send some PWM signal on that wire and see if it heats up or something.

The car is undergoing an engine swap but I should be able to test this some time this week.

[k90]

Originally Posted by blackout_ssri

I'm also very interested in this as I already have the hardware on my car. It's a 2008 330i with the whole AC/heating box thingy from a diesel.

I'll try this week maybe to send some PWM signal on that wire and see if it heats up or something.

The car is undergoing an engine swap but I should be able to test this some time this week.

Dope.
I have yet to get a response from 20-30 junkyards I sent a message to asking for intact 100A PTC supply cable from battery fuse box to PTC. And the PTC too.