Push Button Start

#1

I have searched the forums for over an hour and i can’t find it: Can anyone tell me a simple way to bypass the ignition switch and key and install a starter button?

Thanks

#2

Using the wiring diagrams at http://wedophones.com/BMWManualsLead.htm, identify the Hot in Run and Start and the Start wires under the column. You’ll need a switch that can handle the Hot in Run and Start current (~30a) and most any push button switch for the starter. You can pick up Hot at all Times power for the ignition switch under the column or at the power point in the engine bay. Pick up power for the Start switch from the switched side of your ignition switch.

That is the easy way, but it means there is no drive-away protection. What I did was to add a relay that provides Hot in Run and Start power to the mix. Coil power to the relay is from the Accessory function of the ignition switch. The ignition toggle switch turns on the relay. So the key has to be in the ignition and turned to position 1 or 2 for the engine to start or run. Take the key out and everything is dead.

#3

Thank you!

#4

So it looks like i wire the bk/yl through the switch to the red, then the push button between the green wires. Turn the switch “on” and it completes the circuit for “run”, then the push button will activate the starter. Am I on the right track here?

#5

Before going further I need to know exactly what the end goal is. Simply adding push button to control the starter is one thing, eliminating the ignition switch completely is another.

In the latter case, you will need to use 30a relays to power the 2.5mm Violet wires and the Green wire under the column if you turn on the ignition with a toggle switch or you could use a high power switch good for ~50a and connect all three to the cold side of the switch. There is a reason those wires have 2.5mm cores… The Black/Yellow wire is the solenoid control. That pushbutton should get power from the switched side of the Green.

#6

[quote=“jlevie” post=70052]Before going further I need to know exactly what the end goal is. Simply adding push button to control the starter is one thing, eliminating the ignition switch completely is another.

In the latter case, you will need to use 30a relays to power the 2.5mm Violet wires and the Green wire under the column if you turn on the ignition with a toggle switch or you could use a high power switch good for ~50a and connect all three to the cold side of the switch. There is a reason those wires have 2.5mm cores… The Black/Yellow wire is the solenoid control. That pushbutton should get power from the switched side of the Green.[/quote]

I completely removed all the steering column stalk and integrated a push button start and mil-spec ignition switch so it can’t be knocked into the off position by accident. (Not those lame looking aircraft red flap switches) It pulls out and up, lock and vice versa for off.

The key is that you will need to integrate two relays because you do not want to run that current through the switches (you will either get shocked or it will just blow the switch out depending on the quality of switch you use.

I’ll post some pics next week when I get back from traveling.

#7

Would this work? It has a 40amp Switch.

HERE

#8

Probably, however, I would personally use a standard relay so that you can use almost any switch. Plus if something breaks, parts are easily sourced and you’re not stranded.