E90 Push-Start/STOP Switch DIY....?? - Page 2 - United Bimmer Community

**Kiterunner** · 02-11-2007, 07:51 AM

Quote:

Originally Posted by QcMarque

yes, you'd need the key in the ignition on the 'run' position. if you wanted to not need the key (which I'd think would be a great security risk) I can look into that as well so that you'd have an on/off switch then the start button.

There are two options in the wiring of the PSS Switch. One, if you wish to shut-off the engine using the ignition/ key. The second, using the PSS switch.

Managed to get hold of some Circuit daigrams of E90 PSS switch from the local Bimmer dealer...the race is on mcQ...!!!!

**QcMarque** · 02-11-2007, 03:31 PM

I have a start button wired up in my car right now... the only thing you have to do for that is wire the button between the green ignition wire and the starter relay under the dash (if you get the Z8 button, there's a safety feature in the button... you have a 3rd wire to tap into the hand brake switch which allows the button to engage the starter only when the hand brake is engaged) I'll snap a few pics to show the more simple of the 2 installs (the E90 PSS button install is a little more involved, but not by much)

**QcMarque** · 02-12-2007, 10:56 PM

Here's the basic start button wiring (based on my car... which lead to the relay is used on your car may be different, but the basics are the same regardless):

Keep in mind that with this setup, you CAN run the starter while the car is running. If you use the Z8 start button there's a 3rd wire that is run to the hand brake wiring to allow you to run the starter only while the hand brake is set.

**Kiterunner** · 02-17-2007, 09:40 AM

Many thanks QcM..

Will start working on it this weekend, and hopefully have pics for the DIY.

**QcMarque** · 03-20-2007, 12:27 AM

Alrighty... no one has updated anything on this, and I'm sure a few are still wondering how to wire up a start button w/o the need of a toggle switch and here it is(well, will be soon anyhow)... it's wired so you have to have the hand brake pulled and the vehicle in park before the button is functionable.

As soon as I'm able to upload again I'll post the schematic.
I don't know why but I can't upload, or delete any of my previously uploaded files. So... to be continued...

**QcMarque** · 03-20-2007, 05:56 AM

Hey Hey Hey... Here ya go - just remember, the wiring schematic here is based off a 1986 E23 L7... your wiring may be different, so get the ETM/WDS or something of the sort for your car so you can be sure it's wired in properly... I'm not responsible if you burn something out or anything.

The diode allows the button only to be used when both in park and the hand brake engaged, w/o it you should be able to start your car while in park and the hand brake dis-engaged, but then after started you have to have it in park and have the hand brake engaged to run the starter (how I have mine done).

The only thing I've noticed is once the car is started and I put it in gear, both the hand brake and "P" lights VERY dimly glow - until it's put into park, at which point it extinguishes completely. I'm not sure as to why it does this, but it does... perhaps the diode would eliminate this phenominom, but I don't want to pull my center console apart again just to install a diode (though I'm sure that after pondering the point long enough I'll need to know and will do it... lol.)

**fastdriver71** · 10-22-2007, 02:18 PM

Hello All.. I'm new to the Forum and this is my first post!

I'm wondering if someone was able to get the E90 (start/stop) switch to work. If so is there a schematic available that explains the pin outs on the back of the switch.

**kasmankk** · 12-07-2008, 10:44 AM

same here, need help to get e90 PSS to work for an E46.
I just bought the botton, by it turned out to be not a simpale push button,
There are 10 pins on the PSS

**Diokaef** · 01-10-2010, 03:04 PM

http://www.zpost.com/forums/showthre...=336838&page=2

**Diokaef** · 01-10-2010, 03:08 PM

e90 button copy

momentary button 4 pins and not 10

http://www.digitalguarddog.com/mm5/m...ry_Code=a20001

**netmgr** · 07-05-2010, 07:10 AM

Heres my website that details how to fit the E90 start button to an E39

www.netmgr.co.uk

**johnsmith10** · 02-17-2011, 05:01 PM

Quote:

Originally Posted by netmgr

Heres my website that details how to fit the E90 start button to an E39

www.netmgr.co.uk

It's amaaAzing!!

the video is great!
As I've seen, you don't move the key at all, right? Please correct me if I'm mistaken. You just insert the key, and puch the button? Does it kill the engine when u press it again?
I've seen some mods on other boards, they used z4 start button, and it was just for startin the engine & they have to move the key to position 2.
I'm very interested in this mod, and I really wish I can have it on my car.
Would you please add some details about how to wire the button.
I'd beg for that!!

Thanks in advance to all of you guys!

**netmgr** · 02-17-2011, 05:32 PM

its not an easy mod im sorry, you cant just use it as a switch - you need a microprocessor circuit to control the ignition circuits.

But yes one press of the button starts the car, another stops it - holding the button in just turns on the ignition but doesnt start it - you dont touch the key at all.

Unless you can understand PIC chips and circuit design its not possible.

**johnsmith10** · 03-05-2011, 03:02 AM

Quote:

Originally Posted by netmgr

its not an easy mod im sorry, you cant just use it as a switch - you need a microprocessor circuit to control the ignition circuits.

But yes one press of the button starts the car, another stops it - holding the button in just turns on the ignition but doesnt start it - you dont touch the key at all.

Unless you can understand PIC chips and circuit design its not possible.

thanks a lot for your reply..
Actually, I've been askin for help.. one of my friends has a good knowledge of electronics( he is an engineer) but no knowledge of cars

.. and he asked me if I can get any brief description of the microprocessor circuit..
I'd really appreciate your help if you can provide me with any more information to tell him what to do, as i'm very interested in this mod.
regards,

**netmgr** · 03-07-2011, 09:37 AM

Quote:

Originally Posted by johnsmith10

thanks a lot for your reply..
Actually, I've been askin for help.. one of my friends has a good knowledge of electronics( he is an engineer) but no knowledge of cars

.. and he asked me if I can get any brief description of the microprocessor circuit..
I'd really appreciate your help if you can provide me with any more information to tell him what to do, as i'm very interested in this mod.
regards,

Sorry you're on your own with that one!
if all you want is the button to fire the starter motor, ie you turn the key, then press the button and use the key to turn off the car then its easy no problem for most people with a little circuit knowledge, but then whats the point of that!

But if you want the button to do as mine does which is it does everything, ie each step of the original key switch is done by holding the button, start the engine and stop it then you need an intelligent switch controlled by a microprocessor running a program, which you need to write in assembly language! mines about 50 lines of code - you also need to detect when the engine has started to run and turn off the starter motor.

I used a 10f200 PIC chip, but as I said its not easy and not worth the effort - you still need the key because theres no way to bypass EWS on the later BMWs which also need the key to be inserted into the ignition to charge the central locking circuit in the key and then theres the steering lock, and the auto gear lever lock etc etc...