[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.

[k90]

Anyone have disposable IHKA panel laying around for teardown and photos?
Pin10 signal paths from both connectors is the interesting bit.

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.

Did you end up you testing it or did you Blackout?
Do you have power connected to your PTC? Sounds unlikelly.

[k90]

Still some winter and cold weather left. Found the PTC with cable stubs.

61136925116902 is the positive connector. Has a cylinderical high-amperage spring contact. Positive terminal pole is 6mm diameter. I bet you cannot buy that connector new, but need to get a heater with a stub of a positive lead.

Positive lead is ~11AWG. Pretty thin given the peak power amps around 75A or so.
EDIT: a particular information system says positive lead is 10.0 meaning 10mm2 that makes more sense.
EDIT: AWG gauge in the photo is sus af. It actually goes into scrap now.

837723403 is the 4pin signal connector. Only 3populated contacts.
EDITEDIT: it's the ground that signal connector is lacking as the grounding lead is used as ground for signal too. Pin1(Red): Servo voltage, Pin3(Black): PWM, Pin4(Green? Mine yellow): LIN bus.

I think I could characterize PWM signal from friend's 1-series diesel. Should have the same heater?
EDIT: I can and it does.

[k90]

I use this thread as a notebook of sorts if you don't mind.

Got around to measure friend's 1-series DDE signal to IHKA:

• PWM frequency 170hz
• 12V signal - active low
• 0 Power duty cycle is 96% high (DDE is awake, but engine is not running)
• Full power duty cycle is 94% low (75A confirmed from ground lead)
• State for DDE asleep was not measured at this time which is not good
• State for coolant temp above 75C was not measured at this time

Opened the IHKA panel just for fun:

• Pin10 is directly connected to Pin10 and apparently nothing else that multimeter could pick. Copper path was not traceable in top and bottom layers.
• Assumption is that IHKA does not alter PWM signal in any way.
• IHKA didn't have separate EEPROM chip on board. Does IHKA even have any coding options? Would it even need any coding options? Maybe it's function is static regardless of platform.

Opened the PTC heater:

• PWM pin circuit has filter cap to ground and 16kohm series resistor that branches to MCU input pin and 5.1V zener to ground.
• Doesn't have any separate pull-up or pull-down circuit for PWM, but I assume MCU has weak pull-up active to internal logic voltage level in case of floating signal.
• Assumption is that +12V driver for PWM is unnecessary, but ie. 5volt signal would do just fine. Also PWM pin seems to be strictly an input.

Questions:
Anyone know the factory installation location of positive lead from battery fusebox to PTC? Just tear the car apart and install the cable?
Does anyone have DDEs at hand to see which voltage supply rail pulls up PWM signal to 12V?

[k90]

Ordered a N47 DDE for reversing the PWM circuit to make it 100% kosher including correct 12v terminal for supply. The cheapest one possible from ebay - not expensive at all. Then I can toss it to my friend with N47 for spare / general f'ing around. So that solves that.

Also I need to scrap that suspisious AWG gauge I have. AWG markings are totally off. The cable is actually ~4mm conductor diameter which lands it at 7AWG / 10mm2.

Anyone(audio guys possibly?) know the name for connector system for rear fuse terminals? I think I'll pull the ground lead and after a while disconnect the one going to jump start point / engine electronics I guess. Usually all the connectors have a bmw product number. Not finding it from realoem.com is generally a bad sign.
EDIT: I disconnected it and the 1-width connector for engine electronics in the photo is 6113 6925170-02. Next position that is for electric heater + auxiliary heater is 2-width. But there should be at least 2 free 100A fuses with 1-width too color coded for various stuff that is not present in this car.

For cable routing I guess it needs to run with junction box supply cable inside the car at passenger side. Diesel guys have you seen 2 red leads appearing behind junction box? Gasoline have just one that goes to junction box. Wondering if the cable goes all the way to firewall before making a turn to left.

EDIT: I was about to install a wire for BSD signal from DME for data capture and later to install microcontroller board to. Luckilly I didn't shove down the connector. Socket terminals have flat contacts in DME! That would have ruined my day.

Correct socket terminal types for MSV70 signals:
12527522387 Socket terminal MQS1.2 0,35-0,5MM² SN
12527522388 Socket terminal MQS1.2 0,75-1,5MM² SN

[Andystobbs]

Number 14 is the plug for rear power distribution

[Andystobbs]

From memory the PTC supply goes directly to the PTC.

[k90]

Originally Posted by Andystobbs

Number 14 is the plug for rear power distribution

Connector system is called MAK8 and a lot of google results is a good sign! Also found it from realoem.com now. It was actually on the page I was looking earlier just forgot to scroll down.
Thanks!

Contacts:

61136920092 Flat-type connector MAK8 2,5-4MM²
61136920094 Flat-type connector MAK8 6-10MM²


Housings:

61136925176 Universal socket housing MAK8, uncoded 1 POL
61136925166 Universal socket housing MAK8, uncoded 2 POL

Originally Posted by Andystobbs

From memory the PTC supply goes directly to the PTC.

Yes. Only rear distribution box fuse is between PTC and battery. PTC controller board inside the heater does all the switching and PTC elements are inherently safe.

Do you mean directly as in how the wire is routed? I doubt that there would be diagonal routing across the floors. It's goes above transmission tunnel or at passenger side. Or it goes passenger side half way and then diverts to running above transmission tunnel. Friend's 1-series didn't have center console installed and there was PTC ground lead bolted to ground post and a bundle of twisted pairs above carpet. Didn't see thick red wire above the carpet at least. I might need to tear down my friend's 1-series. He likes it when I arrive to his house and start pulling panels from his car. "I need to remove your interior real quick"

Next I should capture BSD and write a protocol decoder for the logic analyzer software to see if I could make sense of the data communication between DME and alternator.

[k90]

N47 DDE arrived.. a while ago.
I would call opening that tin can semi-destructive process. Definitelly required some flathead screwdriver violence and some sweat.

Winter is over but there are still cold spells left for testing if I pick up the pace.

Supply notes from N47 DDE:

• In this case all 3 supply pins in collumn are actually all interconnected on the board. Even the one that has different color strip on wire. The whole board has only one supply region.
  This is very different from MSV70 DME that has a ton different of supply pins and definitelly separate regions on-board as it has supply via multiple fuses.
  .
• Realized that engine bay is totally cold(apart from starter and alternator) unless 15WUP signal provided to DDE energizes engine electronics relay that supplies power for everything including the DDE itself.
  Again a bit different vs. MSV70 DME which has all but one supply pin switched by the relay. One remaining hot all the time. Why?
  .
• Inrelevant note:15WUP goes to a particular Bosch multi-output switch IC that drives the relay. There is no indication that DDE's microcontroller even knows the state of 15WUP. Basically 15WUP seems to just drive low-side transistor that drives the relay. No latch mechanisms or overdrive from microcontroller visible unless operated via internal mechanisms of switch IC somehow.
  Testing prooves otherwise. Without 15WUP board stays inactive. After activation jumper to 15WUP was cut and board stayed active. Don't know about relay output state if it stayed latched or not after cutting 15WUP jumper.
  .
• Conclusion: PWM generation should be powered from engine electronics relay.

Electric heater PWM notes from N47 DDE:

• PWM signal is connected to another Bosch multi-output low-side switch. Only low-side transistor found with diode mode from ground. High-side transistor not found with diode mode to all of the pins of the switch package or DDE supply. All pins connected to IC seem to be low-side of different electric loads inside engine bay.
  .
• Inrelevant note: There appears to be at least one output to pin connected to that low-side switch that is marked as unused. If you ever need an output and have skills to add your routine to engine controller firmware there is likelly unused output somewhere to find. That's beyond my skillset and the purpose of the project at this phase though.
  .
• No pullup resistor found from DDE. Resistance measurement says circuit is open and also cont. tests against all of the relevant package size resistors on the board.
  .
• This particular DDE has PWM frequency of 160hz for some reason.
  .
• Conclusion 1: Waveform generation should stop and driver should assume high impendance state when engine electronics relay is switched off.
  .
• Conclusion 2: Measurements show that 12v pullup(measured from friend's 1-series) resides elsewhere and for PWM signal generation a simple low-side transistor circuit or low-side switch IC should do. DDE's Low-side switch has what I think is line probing voltage(5V) for short/open detections.

BSD notes from N47 DDE:

• There was at least 3 unused BSD pins if you ever need one there is likelly no need to touch other wires. Usually located next to pairs of used BSD pins and marked as unused.
  Marked as unused doesn't mean unconnected.
  They had bold plans to have way more BSD accesories?
  .
• 1075ohm master pullup to DDE supply(switched by engine electronics relay).
  .
• Connected to bosch custom IC via 10ohm series resistor. Expected dedicated LIN-tranceiver, but they have integrated everything into these in-house custom ICs. Makes sense.
  

Photos:

1. Test setup. 15WUP tied to + and PWM has pullup resistor to +.
2. W/ external pullup(this is how it looks like when measured from IHKA connector)
3. W/O external pullup