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I work for a small run electronics manufacturer so if you don't have manufacturing capabilities available once the design finalized I could get the tooling done for next nothing or no cost at all.
I work for a small run electronics manufacturer so if you don't have manufacturing capabilities available once the design finalized I could get the tooling done for next nothing or no cost at all.
Mike
I can definitely look into it if/when I get done with this little project. It shouldn't be that difficult as you would just have a controller similar to the one I'm looking at designing, but with 3 "switches" that it would emulate the ones that come with the package when it sees the messages from dash buttons. The only "issue" I can foresee is that you'd have to add a module to each seat, but that shouldn't be that bad if t the cost comes in at or below $30 a module. I have a tendency to not see projects through all the way if I get ahead of myself, so I'm going to put that in the back of my mind for now.
As for the tooling, I might take you up on it. We will have to see as this project progresses what the final product will look like and what the required manufacturable it is. My goal is to make it as easy to install as possible while still looking like an of-the-shelf product.
I took a peak under the seats when I got home and noticed that the wiring is not there for heated/cooled seat module, which means that this adapter module will have to go in the dash to prevent each seat from needing a separate module. Apparently Ford uses the same connector for both the heated and heated/cooled seats and combined the pinout (the heated/cooled pinout is left blank on the heated setup and visa versa). One other thing that I'm going to work on is making sure the module wakes on a CAN signal and that it has low power consumption in its low power state so the adapter module doesn't drain your vehicle's battery.
Another update: I plugged the original bezel back into my truck to gather all the information I need design. I also tore the same module down to to see how Ford did their controls. The tentative PCB design is done and I'm going to reverse-engineer the CAN information tomorrow along with double and triple checking my PCB design. If I did everything right, it will take about two weeks to get the proto boards back from fab. I will then populate the components, program the micro, and add pigtail wires. After that, I just have to splice in the 9 wires and test it out. For the "production" solution, I would end up potting the board into an enclosure currently spec'd to 2.5" x 1.5", but I might be able to go smaller seeing as how the board is currently 1.8" x 1.0".
For info on my findings with the old bezel, see the following comments:
Ford uses a transistor (BTS 6143 D) to control the current for each heated seat (see image below)
Each seat pulls between 4 and 5 amps when heating (pulls more current at startup due to colder temps of material).
The controller references the seats' sensor voltages to trigger the on/off states of the transistors. It instantaneously turns on or off when the sensor line crosses the correlating values below.
Low Temp - 2.63v
Medium Temp - 2.33v
High Temp - 2.13v
Last edited by Fiasco17; Nov 12, 2019 at 11:20 AM.
I ended up sniffing the 125kbps bus (MS bus) last night and found everything that I needed to make this work. I've attached the results I found below, and after running a quick search, I realized there is a CAN database library on GitHub with a bunch of proprietary OEM messages already decoded. I used those libraries to confirm what I already found without them and it looks like there are a couple discrepancies. Like some on this forum have already stated, I found that there is the diagnostic connector behind the ODBII port that has both the 500kbps (maybe 250kbps) HS3 bus and the 125kbps MS bus available and unfiltered by the gateway. I ordered a
so I don't have to use puncture probes moving forward. I'm sorry if I'm repeating a few things that are on this forum already. It's just nice to have all the associated information on one thread for anybody interested on the topic.
Heated/Cooled Seat CAN Sniff Results:
Message ID 124h (292d) is the Seat Climate Control Command on the MS bus
First byte of the message is the driver's seat with the values being:
80h (128d) for high heating
40h (64d) for medium heating
20h (32d) for low heating
10h (16d) for high cooling
08h (8d) for medium cooling
04h (4d) for low cooling
Second byte of the message is the passenger's seat with the values the same as the driver's seat
Message ID 355h (853d) is the Climate Control Status on the MS bus. My information on this message did not match the open-source databases on GitHub
Second byte of the message contains the driver's seat status with the first three bits. This is called Overriding_ModeReq in the open database. The values are:
06h (06d) for high heating
05h (05d) for medium heating
04h (04d) for low heating
03h (03d) for high cooling
02h (02d) for medium cooling
01h (01d) for low cooling
Eighth byte of the message contains the driver's seat status with the last three bits. This is called MultipleButtonPressReq in the open database. The values are the same as the driver's seat.
I attempted to command changes from my CAN module without any luck. Sending the 355h message causes the display's status to change briefly but does not stick. My belief now is the commands might be done on the HS bus and the MS bus is just providing the status'. My intention is to understand how the states can be commanded for the potential use on a Katzkin/aftermarket interface (as mentioned by OCMike). I do not intend to do that upgrade myself as my friend's truck has the the factory cooled seats and it doesn't seem to make much difference to me during the Minnesota summers, but I would gladly assist with somebody else's setup. I definitely wouldn't turn down a supplementary set in return for the development of a OEM interface module if the option ever came up.
With all of that information, I will now be doing a couple check-backs on the PCB, possibly cleaning up the organization and trace routing, and will get it sent off for fabrication within the next 2 days. This will probably be the last update before I receive the PCBs and start testing, which is likely to be around 2 weeks. To make up for those 2 weeks, attached are the current PCB designs.
I ordered the boards on Thursday and I expect them around Thanksgiving. I will provide feedback once I populate the components and run basic functional testing off and on vehicle.
For people interested, I'll be starting a separate thread for another module I'm going to be working on for accessory control with a keyfob. I just bought a 1 mile Viper 2-way setup that has 4 auxiliary controls on it and I'm going to be working on a generic CAN module that can be pre-programmed to turn things on/off with input signals (i.e. turn on bed lights, full A/C, full heat, open windows, open sun roof, etc). I probably won't start that until Christmas since I want to get this one done first.
