The driver's side seat heater on my 06 MCS comes on with two green lights for about twol to three minutes. Then it turns itself off, maybe sooner.

I turn it back on and it stays on for another minute and back off again.

Then it won't turn on again.

The passenger side works nicely.

I'm guessing either a bad switch or bad relay. My Bentley manual is on order. Can someone tell me where the seat heat relays are?

YD

 

The relays are intergrated into the switch module. I think they're solid state. There are no other relays. I know this because I bought the MINI kit and retrofitted heated seats into an 04 MCS. Go to motoringfile and search for heated seat retrofit and dlwnload the PDF instruction sheet. It'll tell you everything about that circuit.

My guess is that the one of the heating elements is either broken or short circuited.

Rawhyde

 

The seat heater 'switches' are much more than simple switches. Each one is a microprocessor based temperature controller. There is safety features built into the seat heater system. The seat hetaers themselves have the heating element itself, plus an integrated temperature sensor. The seat heater control sends power to the heater then watches the temp via the integrated sensor. Once the temp has risen to the set point (hi or lo), the switch modulates the heater power to maintain the temp. If the temp sensor is bad, or the controlling part of the circuitry has failed, making the temp too hot for example, the system will lock out after a certain period of time.

Aside from the heater itself, everything else that makes up the system is in the control assembly. The control comes complete with both switches and the mirror control switch. A semi-simple means of determining if the cause is in the switch or the seat is to either borrow someone else's switch, or swap the connectors between the two switches (they are identical except for the plastic connector lock that allows each individual terminal to fit the respective side controller). You'd have to do some minor surgery on the switch to remove the connector locking housing from each switch and then swap the switches in the housing. If the problem stays on one side, it's the heater. if it's now on the other side, it's the switch.

 

'06 = warranty = dealer.
my .02

 

Rayhyde, Greatbear and Willum,

Thanks for the information. It still is hard for me to get used to the idea or like the idea that that much resistance current is being handled by a little switch all alone. But I certainly believe you. I will do the switch swap and see what happens. That will narrow it down. If it is a switch, I'll just swap them and be happy... no one ever uses the passenger seat anyway.

Thanks again.

Willum, thanks for your $.02, but to drive 180 miles each way for something like this difficult for me to consider.
Driving that long, using that much gas, consuming all day is hard to justify. Notwithstanding this seat heat thing, there is nothing wrong with my 06 "yet". If something expensive goes wrong, then that is another story. I won't even be going back for my "free" oil change if I can get away with it. But seriously, thanks for responding.

YD

 

If I had to travel that far (mine's only 50mi. each way and it can be a pain), I'd be looking at doing exactly what your doing......diagnose and fix it myself, but keep it in mind for that "real" trip to the dealer. Minimal warranty issues here ('05 delivered in Aug '04) and $22 at "wallymart" for a jug of Mobil 1 Full Synthetic + $8 for the filter + a fumoto drain valve and all 's here.

 

The 'solid state' switches used in some many different applications these days make traditional relays look quaint and old-school by comparison. The switching MOSFET transistor/driver used just in the seat heater switch can handle over 30 amps without breaking a sweat, and it's about the size of a tic-tac. In fact, there are two, one used to turn on the circuit, the other to do the modulating. This is also a failsafe, if one were to fail in the 'on' state, the other is there to break the circuit. Almost all the exterior and all the interior lighting is controlled via solid state switching. The electric power steering pump is also controlled and modulated through a solid state controller in the motor, and it's capable of handling over 100 amps. It's also been known to fail in the 'on' state too, draining the battery.

 

I just completed my first preliminary diagnostic round.

Pulled the MINI out in the driveway to wash it. Turned on both heated seats. The driver's seat immediately went off. I turned it back on and left the key on and proceeded to wash the car. Twenty minutes later both are still on. So after drying it I just got in and sat. Two minutes later the driver's seat went off.

This appears to be a t-stat deciding it is hot enough and turning off. Not sure. A couple of time it would come back on, a couple of time not.

Tonight I will switch the switches from left to right and see what happens. Thanks for your help.

Those wires to the switches still don't appear to me to be large enough (30A should be 10ga, right) unless this is a pulsing wave output... hummmm. Is there a SCR in that switch????

YD

 

I pulled the switches out and removed the connectors and now see what Greatbear was talking about. There is a little tab on the electric plugs that are different. Left only fits left and so on. It would be easy to take an exacto knife and trim that piece so I can swap them, but I noticed another clue. When I moved around in the seat, the heater would go off. Wiggle off, wiggle off. Hummmm

The passenger side will stay on till the cows come home.

I raised the seat up and found about six separate electrical harness connectors under there. All were tight, but I separated each of them and reconnected them and then sat and wiggled... heater stayed on.... maybeeeeeeee????

I'll just have to drive and watch. I'll keep you posted.

YD

 

Well, it appears I fixed the seat heater... it heats continusouly as long as the button is pushed...

Butttt, in disconnecting and reconnecting all the connectors under the drivers seat.... I now have actived the airbag light.

I've read the FM and all it says is to take it to the dealer.

Anyone have opinions as to how to reset the airbag light?

If it stays on for several days, I'll just pull the battery cable and see if that resets it.

YD

 

I hate to be the bearer of bad news, but once it's on, it's on. The only way to turn it off is the dealer, or one of the hyper-advanced scan tools that runs on a laptop and costs ~$500. When I installed heated seats in that 04 MCS, I triggered the blessed thing on that car and it had to go to the stealership for a reset....

Rawhyde

PS If it's a yellow connector, don't mess with it....

 

Thanks but too late for me.

Looks like I'll get to figure out how to remove that bulb.

thanks

YD

 

you said that the seat heater stayed on until you got in and sat down? if so that points right at the seat heater mat. i've heared of this happening before it will work fine until someone sits in it. nad it turns out to be a small short in the heater mat,and that will be covered under warranty. and yes if you unplugged the yellow connector or the blue connector under your seat with the ingintion on the air bag light will be on untill you take it to the dealership for them to turn it off. the only time an airbag light will come on and then go back off on a mini is if it sences a fault for the actual buckle switch in the front seat belt buckles. all other faults stay on until they are corrected

 

My seat heater problem appears to be from one of the connectors. I unplugged them all and then reconnected them and the heater works fine now... it stays on continuously until you turn off the ignition switch or the heater switch...

Unfortunately, I also unplugged the airbag wires too and now I have the light on the dash.

So disconnecting the battery won't reset the airbag light?

What will the disconnection of the battery erase other than radio presets?

YD

 

actually if you dissconnect the batt it own't erase radio present, assumeing you have a stock radio. it will however erase the time on the clock. and maybe some of the on board computer readings but that is about it. as far as airbag lights it'll still be on.

 

it's like we are sharing a brain ...that was my thought

 

Y

 

My 06 MCS is having problems with the passenger seat heater button.
When I push the button it flashes and doesn't stay on... but this does not happen all the time... sometimes it works and sometimes it doesn't... no rhyme or reason.

Thankfully I am taking it in to the dealer on Monday for it's first service so this is another thing I am adding to the list...