Topic: push button start wiring problem

[MT yota]

I put a push button start in my truck and got tit to work as long as I turn the key to on. Im trying to eliminate having to use the key. I can get it to where I turn the poewer to the dash on a switch but still have to use the key to make it run and turn off.  then I put it to e relay on got the switch to allow the truck to run when on then flip it and the tgruck turns off, but I still have to turn the key to on. I put it on 2 switches one for power and one to let it run but still have to use the key. Im terrible with electronics and wiring...please help me, I want to replace turning the key with a switch.

[79coyotefrg]

what year truck/runner is this and is it auto or 5 spd

[GNasty 82]

Not to sound like a smart but the electrical diagram in the back of haynes/chilton book is marvelous thing.  But to get started solving your problem, let me sum up your post, just to make sure I understand what you have.

1) a pushbutton hooked, presumably, to the starter relay
and
2) a single switch to turn everything on/off
So your process is to flip the switch to 'on' and press the button to start.

Is all this correct?


Now, I'll drop some notes about typical old style key switch electrical systems.  There are generally 4 main circuits tied into the key switch system:
1) IGN1 - usually includes the primary things that allow the enigine to run, such as the coil and fuel injector relays/fuel pump, if applicable.
2) IGN2 - usually other things of high importance to driving, but not required to run the engine, such as wipers, turn signals and relays and AC/heater blower
3) ACC - usually stuff such as the radio, cig lighter and such.
4) Start - duh! the momentary switch to engage the starter to start the engine.

So, in order to remove the key switch entirely, you have to rewire anything there that you intend to use, with IGN1 and Start being the 2 most critical ones.  Keep in mind, that the switch your using has to be rated for the amount of current that you will be putting through it.  This is one reason why most competition rigs you see with a push button start have a whole panel of switch.  Well, that and safety.

Something else to consider in removing the key switch, the key switch also controls the steering wheel lock, so, if you don't want to turn the key at all, but want to turn, you'll have to remove that mechanism as well, which will leave your steering wheel permanently unlocked.

Now, all this information is relevant to the older vehicles that don't have a computer control of much.  All bets are off if the vehicle is OBDII.

[MT yota [OP]]

sorry it's an 85 ex cab 22re. thinkin a three switch set up plus the momentary switch.

[dntsdad]

You could all this done with a single switch and some relays rather than having three.

You are going to want to use relays anyway. Don't just run the ignition system through a toggle switch please.

[Rocksurfer]

dntsdad has your answer and yes don't try to use the switch with a high voltage/amperage load that would be bad. Use a single switch as a trigger to as many relays needed to turn the power on then a push button also with a relay to crank the starter. Don't know why you'd want to eliminate the key switch since it does the work of a switch and you could use a push button to start.

[GNasty 82]

Just a correction,  relays for the ignition and any other switches is definitely what you want to do, but a relay is by no means required for the starter.  It already has a relay built into it.  The current that would be flowing through the push button for the starter is only a few milliamps.  The starter's main current draw comes over the 2 gauge wire that connects it with the battery and that's on the order of several hundred amps, usually 400-800 amps.