Heated/Cooled seats question

[cairnsy]

Sorry to revive an old thread, but I didnt see any more relevant ones on the search function

2020 Bighorn 2500, Installed seats out of a 21 Laramie 2500.

Curious if anyone had issue's coding in the ventilated seats option on the BCM? I enabled ecuconfig Ventilated seats present, Memory ventilated seats present, seats B front ventilated seats level (Tried both 2 and 3 with no success) but could never get the option to show up in uconnect.

I also noticed that the seatbelt pretensioner connections were missing on the passenger side and I imagine the occupant detection leading to the airbag faults on the passenger side

I am also having the same issue as @tommygunz where the driver side seat will recline fully but wont come back up, comparing the switches on the adjustment for the seats on my old ones looks like plenty is missing there. Anyone have some schematics or know the best place to find some?

 

[tommygunz]

Sorry to revive an old thread, but I didnt see any more relevant ones on the search function

2020 Bighorn 2500, Installed seats out of a 21 Laramie 2500.

Curious if anyone had issue's coding in the ventilated seats option on the BCM? I enabled ecuconfig Ventilated seats present, Memory ventilated seats present, seats B front ventilated seats level (Tried both 2 and 3 with no success) but could never get the option to show up in uconnect.

I also noticed that the seatbelt pretensioner connections were missing on the passenger side and I imagine the occupant detection leading to the airbag faults on the passenger side

I am also having the same issue as @tommygunz where the driver side seat will recline fully but wont come back up, comparing the switches on the adjustment for the seats on my old ones looks like plenty is missing there. Anyone have some schematics or know the best place to find some?

Just verifying that you did unhook the battery for a little bit after playing with the bcm. It should populate in uconnect after that. At least that was my experience. I don't remember off the top of my head what all I changed but I just followed what was posted here. As for the seat recline, mine is still the same, but i went through a divorce and haven't had time to mess with it. A friend of mine did tell me there is a socket under the seat that you can connect a ratchet wrench to and can move the seat manually if that helps @cairnsy.

 

[cairnsy]

Just verifying that you did unhook the battery for a little bit after playing with the bcm. It should populate in uconnect after that. At least that was my experience. I don't remember off the top of my head what all I changed but I just followed what was posted here. As for the seat recline, mine is still the same, but i went through a divorce and haven't had time to mess with it. A friend of mine did tell me there is a socket under the seat that you can connect a ratchet wrench to and can move the seat manually if that helps @cairnsy.

After a few hours the softkeys wound up showing up in Uconnect! Not used to that from my experience using software to add features to other vehicles so I was wondering what was up!

Appreciate the info on the potential manual adjustment, gunna dive into the wiring in a week when I’m back from work. Hoping I can find some diagrams so I can figure out which pins on the passenger seat need resistors to clear the airbag faults, and why the front tilt adjustment on the drivers appears to be shorting something causing the flickering lights and millimetre adjustments

 

[tommygunz]

After a few hours the softkeys wound up showing up in Uconnect! Not used to that from my experience using software to add features to other vehicles so I was wondering what was up!

Appreciate the info on the potential manual adjustment, gunna dive into the wiring in a week when I’m back from work. Hoping I can find some diagrams so I can figure out which pins on the passenger seat need resistors to clear the airbag faults, and why the front tilt adjustment on the drivers appears to be shorting something causing the flickering lights and millimetre adjustments

Keep us posted! I still have my old seats and plan on messing around with it when I have time to do so.
Side question.... Does anyone know the part number for the hard switches for ventilated seats? My dealer is being difficult since I added cooled seats (when they were adamant that they wouldnt work) They are telling me I have to buy the whole center stack. I find that hard to believe that is my only option...

 

[tommygunz]

I had my air bag codes read and this is what popped up if that helps at all

 

[cairnsy]

So after looking at schematics from alldata it appears that the power functions on memory seats are very different than those on the basic power seats. 4 wires from the switch go to the memory seat module which then sends it to the seat motors, Versus individual connections to the motors on the basic power seats (Why I saw way more wires on my original switch vs the one on the new seats). I'll check all my connections on the MSM when i'm home but given were both having the same issue I would already wager its deeper than that. Hopefully I can add in the MSM on the BCM with alfaOBD without the door switches and memory mirrors as I have no intention of adding all that as well. That's my first steps there.

As far as the airbag codes looking at the wiring diagram for the SRS system it shows that (on 2500hd's in my diagram) the occupant detection sensor, seat track position sensor and seatbelt buckle switch/tensioner all share a common connection and with the lack of a pretensioner/buckle switch on my replacement seats (from a 3500 I believe) the common open circuit faults only make sense. Seriously hoping these seats do have occupant detection sensors and they are just wired differently on the 3500's (I cant see why a modern vehicle wouldn't but dont want to pay for another alldata sub). Worst case its resistors to the occupant restraint controller module but I dont really love the idea of messing with the way the passenger SRS system might work in an accident.

Certainly more of a job than I originally thought but i'm looking forward to getting more hands on and trying to figure this one out

 

[cairnsy]

@tommygunz

Small update for ya, Haven't got around to the passenger seat circuit yet because i've been tied up with a couple other projects but I will be doing that soon

In regards to the forward recline issue though it looks like another user on the forum found a solution! (search function on these BB's just doesn't work as well for me as it used to lol). @Nodroj34 found that something from the memory pedal circuit was causing the issue, props to him because I don't think I would have ever found that.

I removed pins 1 & 2 (green/white and green/blue wires I believe) for the C1 memory seat module, its the one located on the backside (by itself) of the memory seat module attached to the bottom of the seat. Drivers seat now functions exactly as it should.

 

[Butt3rzSt0ch]

After a few hours the softkeys wound up showing up in Uconnect! Not used to that from my experience using software to add features to other vehicles so I was wondering what was up!

Appreciate the info on the potential manual adjustment, gunna dive into the wiring in a week when I’m back from work. Hoping I can find some diagrams so I can figure out which pins on the passenger seat need resistors to clear the airbag faults, and why the front tilt adjustment on the drivers appears to be shorting something causing the flickering lights and millimetre adjustments

I just did a seat swap. Can you let me know all the options you enabled using Alfa or whatever you used. I got the soft keys but they are not doing anything yet.

 

[cairnsy]

I just did a seat swap. Can you let me know all the options you enabled using Alfa or whatever you used. I got the soft keys but they are not doing anything yet.

Ventilated seats present, Memory ventilated seats present, seats B front ventilated seats level 3 (for high med low), I’ll have a look through Alfa next days off to verify any other settings for you but I think that was all it took. And some time for the BCM to reset. I recently tried to swap to a phoenix audio head unit and upon restart after swapping back I lost a bunch of options on my OEM Uconnect head unit (fully expecting them to restore down the road at this point). Idk if RAM is storing programs in ram memory (pun intended) but it’s super bizarre how they are running the computers on our trucks. Not used to this in other vehicles but I guess patience is key and appreciating the fact we can code in features.

As for the passenger seat I’ve been too tied up with a few other projects to dive into it deep yet (drivers seat was my main concern lol). Worst case Ontario I am putting resistors into the ODS/seat track sensor circuits at the connectors which would probably be a bummer to most but also the easiest option if we truly don’t have the wiring for those. Sorry for the delay but I do promise I will have an answer for ya’ll eventually

 

[Hankenstine]

OK, this threads been going so long. I think we should just keep it going. Did you guys ever figure out your airbag light after the seat swap? I did the seat swap too, but took the airbags out out of my old seats and I’ve not had any problems with the airbag lights, but I can’t get the hard buttons to work and no soft buttons are showing up in my Uconnect, my HVAC hard buttons are not working either or volume or tuning knobs have turned everything on in Alpha reset the battery left it unplugged for about 45 minutes plug the battery back in Without opening the doors or touching the truck and let it sit for an hour. Soft keys showed up for the climate control in the radio, but don’t work. The heat stuck on fan speed two and you can’t change anything. You guys know what’s going on here.

 

[cairnsy]

Finally got some more time to play around with the truck but came up with some disappointing results. Turns out 2500/3500 seats do have a completely different restraint system setup, hence some people being okay and others having the open circuit issues. I have no intention to completely rip my old seats and new ones apart to transplant the missing occupant detection sensor and seat track position sensor so at this point its probably gunna be resistors in the circuit to make the swap work with no errors (but you effectively defeat the intended design of the passenger airbag system) The only other thing I can think of is if the occupant restraint controller module can be changed in alfa to behave like the 3500's but I'd assume from Jimmys previous replies that there was no luck there.

If anyone is planning on doing this swap in the future I would say it is worth confirming that the seats you purchase came out of the same model truck you are planning on putting them in

 

[JBoze]

I have seen this done before. I thought it was on this forum, but maybe it was another forum, or Youtube. They showed taking the seats apart and adding everything. Maybe it was on the Infotainment site. It's somewhere on the web!

 

[cairnsy]

Howdy everyone, This will hopefully be my last post in the echo chamber because I finally got this one completed and code free.

I made a little harness to allow the seat track position sensor and seat buckle switch to be moved over from my old seats. You could always de-pin or cut the old ones if you want but I will probably be swapping the old seats back when its time to get rid of this thing so I wanted to keep it as clean as possible

*Disclaimer: Do this at your own risk, per all research I have done this circuit is only for the seatbelt warning, with that said I find it weird the seat track position sensor is part of it as that is usually used for disabling the airbag if the seat is too far forward. Know that you are actively tampering with the airbag system and any changes may have unintended consequences in the event of an accident. I am not encouraging anyone to do this mod but only speaking as to how I cleared the error codes*

For the seat buckle switch connector you will need (If you have never made a harness/connectors before order way more than you need, you will likely break them and/or need trial and error to figure out how they work)
1x Yazaki 7282644340 connector
2x Yazaki 7114410102 1.5mm male terminals (I ordered ones for 16-20awg, most connectors per OEM are 22awg but many of the terminals were out of stock in 22awg, I used 20awg with no issue)

For the seat track position sensor you will need
1x TE Connectivity 1438426-3 connector
2x TE Connectivity 1326028-1 0.64mm female terminals

To tie everything back into the xy412a seat connection you will need
3x Yazaki 71141170 2.3mm male terminals

As per my previous post you will need to splice the blue/green side of the seatbelt buckle wire to the green side of the seat track position sensor (I used 3 wire wagos for my splices and used 2 wire wagos for connections to xy412a for troubleshooting purposes) You will need to populate pins 9,10 and 20 with the seat position sensor return, seat buckle supply wire, and seat buckle return wire.

Move your old seatbelt buckle and seat position sensor onto the new seats, plug in the connectors, and you should see codes B0052 and B00C5 are no longer in fault state, But you will still have B2734 for the occupant detection sensor. Go into alfaOBD -> Body computer -> Change vehicle configuration -> Search for Safety: ODS Present -> Set to disabled, this will disable the occupant detection sensor.

Clear all faults and with any luck that should be the end of that for the passenger seat. For the drivers seat you will need to do the memory pedal wire delete I mentioned earlier in the thread, and for soft keys enable the vehicle configs I mentioned earlier as well. Sorry I'm sure photos would have been more helpful for most of you but I am over this one and not pulling the seats out again lol.