Help with wiring diagram for heated seats

[koenig d]

Thinking of putting heated seats in to 1991 850i. I'm stealing them from my 1993 ci. There dosn't appear to be any switch wires near the centre console, and I don't know if relays are involved in the seat operation.
the plugs appear to be the same in both cars. but the ci has an extra 2 wire plug on the pasenger side (secure seat warning ? ) gratefull for any help.
HAPPY NEW YEAR

[TxGR8White]

www.wuffer.net and download the ETM for the 91 and the 93. Thee you can see the complete wiring diagram with components.

[Ziminskas]

I know that this thread is pretty old, but I have a question about the heated seats switch and I thought it might be relevant to this in some way. Is it possible to "extend" the wires from the heated seat switch on my '91 (heated seat switch is on seat) to make them go into the center console like some of the newer models? I just figured it would be worth finding an answer now since I have my seats out and am about to replace my console and dash.
Thanks guys.

[Max Lumens]

Piece of cake. Go here for all the electrical info: http://panasonicmadeeasy.com/BMWManu...51120?468b5010

Been years, but IIRC all the green wires are hot, tie them together. IIRC the blue and yellow stripe wires are the leads to the heaters. Doesn't matter where you ground it, and the cigarette lighter circuit has plenty of juice. All the controls are in the switches.

[Ziminskas]

Thanks! I checked out that link....I wish I knew what it meant...

[8eights]

...or you can just extend the wires into the center console and then ad the switches.

[Ziminskas]

...or you can just extend the wires into the center console and then ad the switches.

That's what I was thinking of doing; but I'm not so great with electronics...splicing and such.

[Max Lumens]

That's what I was thinking of doing; but I'm not so great with electronics...splicing and such.

The only wires you need to run from the seat up to the console are the blue and yellow ones. Solder all the green wires together to one bigger wire and connect it to the hot wire on the cigarrette lighter. Connect the brown wire to the ground on the lighter. Done.

If you're not comfortable with electrical work, probably good to have this done by a Sick Puppy.

[M3C]

Anyone familiar with seat heating switch pins-wires, there are 5 wires on the rear (switch has 6 pins), switch part number 8352259 (for E38 and E39)
I think:
brown/black wire is - ground
gray/red - illumination
white/yellow - ?
white/blue - ?
green/black (with yellow dots) - ?

What are these 3 wires for?

Or if you can provide the pin diagram for this switch.

[revtor]

Not sure what this has to do with the E31, but anyway...

[M3C]

revtor,

when no other place has the info I'm after, this is the only source where i can find it, I have an E36 and would like to use this switch from E38/E39 as an light on/off switch (button) with intensity feature (rotating wheel).
That is the one you are showing, this switch has one button (wiyh green led light) and one wheel.
I am trying to test it with 12V power source and ground, all I see is the green button light comes on for about 1-2 seconds and goes off.
Pin #1 is illum. (it works), pin #4 is ground but 2, 3 & 5 are not clear to me.
I see 2 & 5 are output signals and 3 is input from from fuse 39, if I know is the #3 12V or some other kind of signal input?

[revtor]

I have no information on what's inside the E38/E39 seat heating switch, but I'd be very surprised if it was just a simple switch. If it's anything like the switches in the E31 it contains some sort of MOSFET PWM circuit specifically designed for driving a heating element and not suited for your application without heavy modifications to the switch internals...

Anyway, pin 3 is the power supply for the heating element. This is what is being "switched" inside the switch - the hot side of the switch if you will. Pin 5 is the output - the switched side of the switch (most likely a high frequency PWM signal). Pin 2 is a bit unclear for me as well as it should be an input, not output. It's connected to the temperature sensor in the seat heating element and is probably used as overheating protection.

[M3C]

When connecting 12V on pin3, it reads 8V on pin5 and 3V on pin2 and it does not change after rotating the switch wheel on either side.

I guess this is why when pressing the button, green led is turned on for 1-2 seconds only and goes off, it most likely reads as overheating, this has to do with the signal it is receving from pin2 in this case not connected to a heater sensor (NTC signal).

Was hopping to use the wheel as a led dimmer and the button for on/off function.
It could be an easy modification by jumbing some wires inside or very complicated to a level of not being capable of using the switch for this function.

[sjflat]

I managed to get my hands on a pair of sports seats at the weekend. Unfortunately the car I got them out of didn't have the centre console/buttons so I was unable to tell if the seats are heated. Any thoughts on the best way to check this? (seats are currently out of the car).

Steve

EDIT: In the end I found out the old vehicle's reg number from the breaker's yard and called BMW to see if that car was fitted with heated seats. It was.

[Bio Hazzard]

M3C I like your thinking, I'm about to do the heated seat retrofit myself soon! You could by a simple TEMP sensor from your local electronics store then test it again in the same configuration. I'm almost certain of the functionality of every pin, but did you ever find out what pin3 and pin5 are meant for? I'm guessing pin3 takes terminal15 which should be +12v and sneds it out pin5 to the heated seats

[M3C]

M3C I like your thinking, I'm about to do the heated seat retrofit myself soon! You could by a simple TEMP sensor from your local electronics store then test it again in the same configuration. I'm almost certain of the functionality of every pin, but did you ever find out what pin3 and pin5 are meant for? I'm guessing pin3 takes terminal15 which should be +12v and sneds it out pin5 to the heated seats

Yes pin 3 is 12V power and pin 5 is heating signal it has white/yellow wire color.

[e31gixxxer]

Slightly O/T, but may be of use to someone.

I can't comment on heated seats as I don't have them, who needs them anyway, living in the UK:~)

I used a spare AST switch with the label modified, mounted in the centre consol to run some auxiliary equipment.
The AST switch is a momentary switch and I suspect others are also. This means its contacts are normally open and when you press it the contacts close briefly and then return to open.
I required a press for on, press for off setup. This can be done with relays but more than you would think, 5 relays if you don't use diodes, 2 or 3 if you do.

My solution was to use a latching relay, Durite 0-728-02, http://www.ebay.co.uk/itm/0-728-02-D...item1c1f577a33

One switch, one relay, push on, push off.

[Bio Hazzard]

Slightly O/T, but may be of use to someone.

I can't comment on heated seats as I don't have them, who needs them anyway, living in the UK:~)

I used a spare AST switch with the label modified, mounted in the centre consol to run some auxiliary equipment.
The AST switch is a momentary switch and I suspect others are also. This means its contacts are normally open and when you press it the contacts close briefly and then return to open.
I required a press for on, press for off setup. This can be done with relays but more than you would think, 5 relays if you don't use diodes, 2 or 3 if you do.

My solution was to use a latching relay, Durite 0-728-02, http://www.ebay.co.uk/itm/0-728-02-D...item1c1f577a33

One switch, one relay, push on, push off.

I'm using this setup for various auxiliary switches it works great! I've actually downgraded to the pre 2000 switch panel so I have the flexibility to replace individual switches as I like. The ASC button has has five pins in no particular order 1. backlight 2. GND 3. Switch A 4. Switch B 5. GND switch A + B The PDC switch is similar but it has a small led built in it and only 4 pins which are 1. Backlight 2. LED 3. Switch 4. Ground Jusst putting that out there if anyone needed to know.

[e31gixxxer]

Quote:
Originally Posted by e31gixxxer
Slightly O/T, but may be of use to someone.

I can't comment on heated seats as I don't have them, who needs them anyway, living in the UK:~)

I used a spare AST switch with the label modified, mounted in the centre consol to run some auxiliary equipment.
The AST switch is a momentary switch and I suspect others are also. This means its contacts are normally open and when you press it the contacts close briefly and then return to open.
I required a press for on, press for off setup. This can be done with relays but more than you would think, 5 relays if you don't use diodes, 2 or 3 if you do.

My solution was to use a latching relay, Durite 0-728-02, http://www.ebay.co.uk/itm/0-728-02-D...item1c1f577a33

One switch, one relay, push on, push off.

I'm using this setup for various auxiliary switches it works great! I've actually downgraded to the pre 2000 switch panel so I have the flexibility to replace individual switches as I like. The ASC button has has five pins in no particular order 1. backlight 2. GND 3. Switch A 4. Switch B 5. GND switch A + B The PDC switch is similar but it has a small led built in it and only 4 pins which are 1. Backlight 2. LED 3. Switch 4. Ground Jusst putting that out there if anyone needed to know.

__________________

e31 switches are specific to model and I wanted to keep it stock..ish.

[Bio Hazzard]

The same principle would apply with an e31 but the switches would mount next to the shifter instead of in the dash below the aircon. Switch availability though might be somewhat limited and the switch frame would need to be replaced as well to allow for the full amount of switches to be mounted.



1: Gear lever
2: Automatic Stability Control plus Traction
3: Thiefproofing system LED
4: Programmable electronic power control (EML for 850CSi, or EDC for all others)
5: Electric roller sun blind for rear window
6: Driver seat heating
7: Passenger seat heating

Thats were and how the buttons could be installed, it would maintain a really nice OEM look.

[e31gixxxer]

The same principle would apply with an e31 but the switches would mount next to the shifter instead of in the dash below the aircon.

The e31 switches are next to the shifter. The A/C controls are at the bottom of the dash, as your pic. There are oem removable bezels with various numbers of cut outs to allow for equipment options, that clip in next to the shifter.