M Sport Seat Install - Need some wiring help - PHOTOS

[ANUSTART]

Hello all. So I got a great deal on some M Sport seats. They look absolutely brand new, but, I can't get them working. I've searched and searched but can't seem to find any info on what to do. Any guidance would be appreciated.

I got the old seat removed, the new set in place, disconnected the battery, plugged it in, re-connected the battery and turned the key and got nothing to the seat. This didn't come as any surprise, but I was crossing my fingers. Oddly, there was nothing abnormal happening with the airbag light. It did it's normal on/off and then stayed off.

So my question is, does anyone know how to connect power to the seat? Has anyone done this? I would imagine so. I just can't find any clear info on how to do it or where to connect it into the plug. Is there a retrofit kit for this?

Here are photos of my plugs to illustrate what I have and what I don't.

Thanks everyone!

Current Seat Plug


M Sport Seat Plug


Car Wire Harness

[Hawkeye]

Looks like it'll slide rightin from those pictures... are the plug ends not the same configuration?

[ANUSTART]

My car harness plugged right in, but the seats didn't get any power. I'm guessing the prongs to the left and right of the center cluster give the seat power. Just a guess. Those are missing from the car harness.

As a note I didn't mention the current seats are not power. They have mechanical adjustment.

[Smurfskier]

Are the options the same from onenseat to another? Such as heat, power adjustment? Definitely more pins on the m seat.

[wildag]

Yea, the big pins labeled 16, 14, 25, and 24 are your power lines. Some are for the heaters, some are for the seat movement.

I'm guessing your old seats arn't powered.

We'd need to see a pin view of the car harness to see what's matching up.

[ANUSTART]

No, no power on the old seats. Completely manual and no heat. Not sure if the M seats have heat or not. From looking at the plug it may very well have heat. I'd just be happy with power for now.

[inTgr8r]

Originally Posted by wildag

Yea, the big pins labeled 16, 14, 25, and 24 are your power lines. Some are for the heaters, some are for the seat movement.

^I agree.

[wildag]

Originally Posted by hogzilla

No, no power on the old seats. Completely manual and no heat. Not sure if the M seats have heat or not. From looking at the plug it may very well have heat. I'd just be happy with power for now.

You'll need the connectors/plugs off the car side of a Z4 with the powered seat option. Then run those to the fuse box, and connect them to the 12 volt rail.

You could also do this without the plugs, by cutting the M seat side connector's wires to those power plugs and then making your own car side plug. Radioshack sells all kinds of male/female connectors. The early model Z3 cars used just standard D-sub connectors (white D shaped plugs, found in computer power supplies).

[evoq007]

Since your old seats were not powered, your going to have to run power to the new ones. you can grab a multimeter and try to find some switched 12v under the seat and maybe power the seats that way by splicing those into the m-seats. That would be my suggestion.

[Shipkiller]

From what you said, you did not get an SRS AirBag light. That's good, so that portion of the connector works...

When I get home from work, I will post both pre-2006 and post-2006 electrical diagrams so you can figure out what you need to do.

[ANUSTART]

Shipkiller, thanks so much! BTW, I used your post to properly remove the seat on z4-forum. Thanks!

wildag, that's great advice. Once I gather all needed info I'll probably go that route. My guess is at a minimum I'll need a power line for the motors and one for the driver's side memory function. Not sure what else.

[ANUSTART]

Originally Posted by wildag

We'd need to see a pin view of the car harness to see what's matching up.

I will need to reshoot this one for a better view of the car harness. Can do that tonight. Didn't realize how bad it was till I uploaded it. All the slots are available, but no pins for anything other than what is needed for the SRS sensor. Or so it appears.

[Swanicyouth]

Maybe you already tried this but locate the fuse for power seat and make sure it's present and good.

[ANUSTART]

Originally Posted by Swanicyouth

Maybe you already tried this but locate the fuse for power seat and make sure it's present and good.

I will check and see if anything is labeled for the seat.

Here is a comparison of the plug that is already in the car and the M seat plug. Look I have circled where I will need power to go to potentially. It looks like the center part of the cluster is dedicated to the airbag pad. The outer I'm guessing to be for the electric functions of the seat and heat.

[Shipkiller]

Go to this page on my webserver for some additional help...

http://www.shipkiller.com/Electrial_Diagrams.html

Write up from the electrical manual:

Seat heating
The seat heating system heats the seat cushion area and backrest. The electronics for controlling the selected heating temperature (3 stages) and fault monitoring are integrated in the switching center.

Function
Seat heating can be switched on in three heating stages as from terminal 15 by pressing the button. Three LEDs built into the switching center light to indicate operation. "Terminal 15 active" is signalled to the switching center via the K-bus.

Initially, heating stage 1 is activated when the seat heating is switched on (button pressed once). The seat surface is heated up to approx. 44 °C. All three LEDs light to indicate operation.

By pressing the button once more, the topmost LED goes out and heating stage 2 is activated. The seat is now only heated up to 39 °C.

The seat heating system is switched to heating stage 3 by pressing the button once again. The bottom-most LED lights. The seat is heated up to 35 °C.

The seat heating is switched off by pressing the button once again or switching off the ignition. The seat heating can also be switched off in any heating stage by pressing the push button for longer than 1 second.

The seats are heated by means of carbon fibre heating mats in the main section and steel wires (steel filaments) in the bolster. A carbon fibre heating mat is installed in both the seat cushion section as well as in the backrest. The center sections of the seat and backrest as well as the bolsters of the seat and backrest are always heated. Heating filaments or carbon fibre mats are additionally integrated in the thigh support on sports seats. The seat and backrest bolsters are not heated on the series E39 sports seat with fabric cover.

The temperature is measured by a temperature sensor in the seat upholstery and passed on to switching center.

Monitoring functions
Battery voltage
The electronic seat heating control switches off the power supply to the heating mats if the battery voltage in the vehicle is less than 11.4 V ±0.3 V. The function LEDs however remain on. Power supply to the heating mats is restored when the battery voltage is greater than 12.2 V ±0.3 V for at least 5 seconds.

PC-Board temperature
Due to the fact that the power input of the seat heating system is very high (120 W), the temperature of the pc-board in the switching center is monitored by temperature sensors. Initially, the heating power is reduced as the temperature increases to over 85 °C. The heating is switched off if the pc-board temperature exceeds 95 °C. The function LEDs however remain on. The seat heating cuts in automatically again when the pc-board temperature drops below 85 °C.

Fault monitoring
The electronic seat heating control system monitors the temperature sensor and heating mats for faults. Detected faults are stored in the fault code memory of the switching center.

The following faults can be recognized:

•Short-circuit or line break

•Short-circuit or line break of temperature sensors

•Break in heating mats

If a break or short occurs at the temperature sensor, the seat heating is switched off in order to prevent overheating. The function LEDs are switched off.


Current measurement, seat heating
The current is measured in order to be able to provide a basic statement with regard to a defect in the seat heating system.

Measurement preparation
On vehicles equipped with a switching center in the center console, the current is measured directly at the switching center.

•Switch off seat heating

•Remove center console switching center (A169)

•Measurement is carried out with a 50 A clip-on ammeter

•Unwind insulating tape from wiring harness under seat and attach clip-on ammeter to the wire to be measures.

•Left seat heating: Measurement on HZFA wire (white/yellow, pin 1)
Right seat heating: Measurement on HZBF wire (white/green, pin 13)

•Start engine in order to ensure a system voltage of approx. 13.8 V

System voltage

If the system voltage drops below 11.4 V, the LEDs remain lit but the seat heating is switched off. The seat heating is re-activated as soon as a voltage of at least 12.2 V is permanently applied.

Measurement at DIS tester
•Select "measurement system"

•Measurement function: Current 50 A

•Measurement connection: Clip-on ammeter

•Type of measurement: Direct current =

•Measuring range: +/- 50 A

•Check system voltage with DIS tester

•Switch on seat heater on the side to be measured

Measurement evaluation
Generally applicable for all heating stages: Each heating stage has a certain setpoint temperature. The control unit attempts to reach this temperature as fast as possible. The temperature is the kept constant by means of clocking (= pulsating direct current).

•Generally, the current is approx. 10 A during the heating-up phase (at a system voltage of 13.8 V)

•The heating output is reduced on approaching the setpoint temperature. The clocking function can now be distinctly recognized, i.e. the current pulsates between 0 and approx. 10 A.

•On finally reaching the setpoint temperature, the interval of the 0 A range is extended even longer.

•If the current temperature is higher than the setpoint temperature, e.g. when, after a longer period of operation, the heating is switched back from stage 1 (3 LEDs) to stage 3 (1 LED), no current is applied until the temperature has again dropped to the corresponding setpoint temperature.

Heating-up seat

The duration of the heating-up phase is dependent on the temperature measured at the temperature sensor! The setpoint temperature is reached more quickly at high ambient temperatures (e.g. in summer) or if the seat is preheated. In this case, the clocking cuts in correspondingly earlier.

Measured power

The measured power depends on many different factors. Both the level of the system voltage as well as the type of seat installed and operation of other loads (seat heating on other side, steering wheel heating) play a significant role. The specified value of 10 A is therefore only a reference value.

Setpoint temperatures
The following setpoint temperatures are reached in the three-stage seat heating system:

•Stage 1 operation (3 LEDs lit):
The seat is heated to a setpoint temperature of 35 °C

•Stage 2 operation (2 LEDs lit):
The seat is heated to a setpoint temperature of 39 °C

•Stage 3 operation (1 LED lit):
The seat is heated to a setpoint temperature of 44 °C

Measurement evaluation
•A current of approx. 10 A is applied:
The seat heating is OK

•A current of approx. 5 A is applied:
Defect in heating mat of seat cushion or seat backrest

•No current is applied:
Defect in heating mat of seat cushion and seat backrest

[ANUSTART]

Thanks for posting this info! I will dig through and see what I can come up with.

Chris

[CFoote]

Your current car is missing the power and seat heater wiring. You will need to run positive and negative wires from the battery (make sure to put a fuse in) to the seats. Instead of using the connector, I would cut the positive and negative wires from the connector at the seat, and put your own connector on.

As far as the seat wiring goes for the heated seat, that becomes a little more complex. I would check e46fanatics.com as I believe someone posted the information on the wiring necessary.

Good luck!

[idlook2]

subscribed

I plan on do this soon myself. I have manual heated seats and might be putting in powered heated seats. Didn't expect any power issues thinking everything is pre-wired on bmw's.

As for power, it sounds like the 2 options are to either tap into a nearby wire that has enough voltage or to run wires straight to the battery or fuse box. And probably a fuse in between the added wire to be safe. I'd prefer to tap into wire to make the install cleaner and easier.

[ANUSTART]

Originally Posted by CFoote

Your current car is missing the power and seat heater wiring. You will need to run positive and negative wires from the battery (make sure to put a fuse in) to the seats. Instead of using the connector, I would cut the positive and negative wires from the connector at the seat, and put your own connector on.

As far as the seat wiring goes for the heated seat, that becomes a little more complex. I would check e46fanatics.com as I believe someone posted the information on the wiring necessary.

Good luck!

Chris, a couple questions hopefully you (or someone) can answer. What amp fuse would I need to put inline to adequately protect the circuit? And, how would I find out which of the wires on the seat are for power?

I think I have it isolated to one side or the other. The center appears to be only for the SRS sensor. I just want to make sure when I connect power I don't fry the seat on accident. It's a very comfy seat.

Thanks!

Originally Posted by idlook2

As for power, it sounds like the 2 options are to either tap into a nearby wire that has enough voltage or to run wires straight to the battery or fuse box. And probably a fuse in between the added wire to be safe. I'd prefer to tap into wire to make the install cleaner and easier.

I plan to go to the battery and run wires from there. But we'll see. Fuse box may work fine but want to make sure I have a place for it and don't overload the box. I haven't looked at it yet so not sure. I plan to dig into this over the weekend.

[CFoote]

Originally Posted by hogzilla

Chris, a couple questions hopefully you (or someone) can answer. What amp fuse would I need to put inline to adequately protect the circuit? And, how would I find out which of the wires on the seat are for power?

In your picture, Pins 13 and 14 are your power and ground. To figure out which is which, go online and do a google search for "bmw z4 wiring diagram". You will see a link to the WDS which will show you what is what, along with a listing of color coded wires which is very helpful

Put the fuse (30 amp for each seat) in-line with each positive terminal. You can try wiring these to the fuse panel under the dash, but I will warn you right now that you may damage other wiring in the process. I would leave it alone and just run a nice 10-12 gauge, flexible wire for the +/- terminals.

As I mentioned, that will mean clipping the factory wiring from the connectors. In fact, when you do that, you can take the factory pins right out of the connector for safety reasons.

The smaller pins on the opposite side are for the heated seats. They will also need their own power source. It might not be a bad idea to run a power distribution panel from the battery to behind the seats, and then you could run your wiring from there to the assorted wiring (heated seats, power seats, etc).

Here is a link to a power distribution panel. You would run one large wire (8 gauge should be fine) to the distribution panel, and then you have four outputs -- 2 for seats, 2 for heated function). This distribution panel also has fuses built in which is really nice (just make sure you use 30 for the power seats, and I think its 15 for the heated function? Double check the manual)

http://www.cartoys.com/products/prod...:referralID=NA

To get the memory seat function to work, you will need to run a small K-Bus wire from the seat to the switch panel. Again, using the WDS system I suggested you google above, you will see which wire to tap into to get the memory seat function to work.

That should get you rolling for now.

Chris

[CFoote]

Originally Posted by idlook2

subscribed

I plan on do this soon myself. I have manual heated seats and might be putting in powered heated seats. Didn't expect any power issues thinking everything is pre-wired on bmw's.

As for power, it sounds like the 2 options are to either tap into a nearby wire that has enough voltage or to run wires straight to the battery or fuse box. And probably a fuse in between the added wire to be safe. I'd prefer to tap into wire to make the install cleaner and easier.

For safety reasons I would run seperate wire. When you see the thickness (gauge) of the wiring BMW used on the power seats, you won't find anything nearby that will work, and tapping into existing wiring can cause all sorts of electrical problems (voltage drop mainly being the troublemaker)

Chris

[ANUSTART]

Chris, YOU are my hero today! Thanks so much!

I will take photos and let y'all know how it turns out.