After taping my ducting back together the cooling was working. The heat still isn't though. I may pull the seat apart again and see if I notice anything out of place.

 

I had the heat fail on my driver's side even taping up the ducting wouldn't fix - in the end I replaced the whole module.

My guess was that many repeated attempts to use the heat without sufficient airflow (because it was escaping out of the cracked ducting) burned up the peltier unit inside the seat heater, or maybe the peltier unit just failed anyway. I think it's possible though that if it's run for long enough with air leaks the system will fail.

 

Hey Dave, I've still not addressed by driver's seat other than to ensure the 2 filters are clean and that the duct in seat back is repaired (via duct tape).
Questions for you are:
- do you know if the control unit is interchangeable from driver's to passenger set for troubleshooting purposes?
- where did you source the new control module?
- do you know if the seat bottom also has duct that can crack?
Many thanks in advance for sharing your insights!

 

I suspect driver seat bottom cushion peltier is bad, and have now had opportunity to check passenger side seat for comparison's sake. I know that sounds odd, but passenger works and i wanted to see what it looks like in working order first.. will extract driver's seat soon.

Who has changed the "module" and what did that consist of?

see my pictures of the part - the wires go back to another harness and it looks like might either have to splice in 4 wires or buy an entire assembly with the fan??

anyone have experience with replacing just the peltier device? and a place to buy it?



overall assembly with fan - 1 wire harness

copper element looks clean - this is from operational passenger side seat bottom

4 wire module with part number

 

so the driver's seat is similar, but opposite, layout of the passenger
it has a large control module with a complex looking circuit board.
the copper fin device in both seats looks in great shape and I'm at a loss as to what makes my seat fan turn off after just a few seconds on the driver's side.
the number on the copper fin device seems to be a S/N, rather than a part number (i think)
both fans seem to be in great shape.
there's been theory that a fan isn't moving air enough and a high temperature sensor turns it off - where is this temp sensor?
re: trouble shooting - i have previously repaired the broken duct in driver's seat back. have also selected to turn seat back "OFF" and just run the seat bottom, but similar run cycle happens where it turns off in a matter of seconds
i don't know if it's the entire fan needing replaced in back or bottom or the control module or something incredibly simple
looking for some expert level help.

driver's seat - large module

inside driver seat module cover

driver's seat bottom fan / peltier module

 

The copper fin device is a Peltier module, and the fins are a heatsink. In simple terms, the peltier unit is an electronic heat transfer module, and when you reverse the polarity to the module, it reverses the direction of the heat transfer. This allows it to heat up air as well as cool it down when controlled by the seat climate module. They use these devices in those cheap little mini fridges that take 6x cans of soda (and aren't very good).

I believe the temperature sensor is integral to the peltier unit itself.

From what I understand, when the fans run for a few seconds and then turn off, it's doing an initial self-test where it powers up the peltier module and the fans and checks that the module doesn't get too hot - that's why cracked heat piping (that you mentioned you'd previously repaired) causes these to fail - too much air leaks out between the fan unit and the peltier unit, causing the airflow over the peltier unit to be too low, and a risk of overheating, so the seat climate control module just shuts off any heat to that seat. I suspect turning the seat back OFF doesn't stop it disabling it after a failed self-test where it tests ALL the fans, and that's why you're still seeing a problem.

Based on this, I'd check the repaired "accordion" piping in the seat back. It always seems to be that bit that fails. I tried repairing mine and it worked for a while and then failed even though the repair still seemed good - the only fix I had was to replace the entire module for a new one (from memory, around $150). At a guess, too many tests performed on startup with not enough airflow eventually kills the peltier unit such that even if you repair the piping, it still won't work.

 

Attached is dealer training for seats - heated only and climate.

 

Dave - as always, I'm mesmerized and outclassed by the wealth of knowledge you've attained, accumulated and kindly redistribute to us all sir - thank you!

I'll check out the seat back duct again.

quick question - when you say module for $150, is that the fan module for seat bottom / back or? I've have the fan modules previously quoted for $400 each.

(fun fact, look up parts pricing for the seats - and gasp - headrests are like $900 and such. entire seat purchased part by part is likely $20k.!!)

 

Sorry, I was using the word "module" far too much! It was the fan module for the seat back, and maybe I'm mis-remembering prices I paid here but holy **** they are expensive now.

I wonder if this is like the 6.35mm timing chain components where they have a limited supply and they're running out? I think it's got to the point now where we need to start identifying suppliers for (at the least) the peltier module, as well as an alternative replacement for the duct piping.