Engine crank with button

hi all, i am putting in a button that will start a vehicle (simply crank the engine). The vehicle we are working on is an '02 Corvette. what should be a fairly simple thing is driving me crazy because it is not working. What we want to happen is when the driver puts the key in, turns it to the RUN position, and then simply pushes the momentary push button that is installed. Since the actual key will be inserted and turned to RUN, EVERYTHING should be taken care of except the YELLOW starter wire. We tested to see that the yellow starter wire IS getting 12 volts when the push button is pressed but the engine still does not crank. There is an alarm in the car but it is DISARMED so it should not be affecting anything. And yet if you turn the key past run, the engine will crank right up. As far as i know, the turning of the key past run simply provides 12 volts to the yellow starter wire. so if the button is providing 12 volts to the yellow starter wire while the key is in the run position shouldn't the engine start? HELP! Thanks, John

hello i remember doing one of these cars a while ago and there was something tricky. there is a yellow and black wire it can be used as a starter kill if the wire is cut it will not allow the car to start. aslo test this wire., i believe it shows a ground signal when your cranking the car. so what you would have to do its take that momentary switch and wire two relays once side of switch ground. other side of switch connect two wires take one wire and connect it to relay 1 relay one setup pin 85 wire from switch pin 86 constant 12 volts pin 87 constant 12 volts pin 30 connect to starter wire. relay two pin 85 wire from switch pin 86 constan 12 volts pin 87 ground pin 30 to yellow black wire. this wire is located at the bcm. try that Jon

Installer/Help Technician

---coral springs florida---

mecp certification is not always needed. I have it and it has not helped me out at all. my experience out shines it.

If the key is turned all the way to the run position, then there shouldnt be any issue with any starter kill. The car see's the key and its resistor pellet and thinks everything is okay to start. Since the key is in the run position, the ONLY wire i can think of that needs 12 volts is the yellow starter wire. that is the only thing that happens when you turn the key to the next step (starter position). subsequently, if the key is in run, you should be able to apply 12 volts to that yellow wire (from a relay controlled by a push button) and crank the car. i tested the relay output and it does give the yellow starter wire 12 volts when the button is pushed - but then engine still doesnt crank. whats weird is you let off the button we installed, turn the key slightly to the right and it cranks. whats different about these two scenarios? John

we are tapping the wires right at the ignition switch where the key goes in. with the button being pressed, we are simply emulating the key being turned one more notch to "crank". so instead of the key/cylinder giving the yellow wire 12 volts, we provide 12 volts to the yellow wire from a relay. its a very simple setup and it should work just fine. since the key is in, its not a VATS problem because it sees the resistor pellet and its not a starter kill issue because no alarm is armed. If you sit there with the key in the RUN position and push the button supplying 12 volts to the yellow starter wire, it wont crank. Yet, when you release the button and turn the key one more notch, it cranks. I'm confused why this simple thing wont work.

there is no second starter wire. the auto start alarm in the vehicle uses only one yellow wire (and it works). and for your second idea, the key is never in the crank position when using the button. it is in the run position and we checked that all the accessory wires are getting the voltage they need, and they are. still scratching our heads..... John

I have a quick thing to try. Run a wire from the starter under the hood to the button in the vehicle and see if you can trip it right a t the starter. If you can than just disconeect that wire you quickly ran and properly run it to the starter and then your button is done. I ran into this problem on a toyota before and that was the only solution I could come up with and its still working fine.

I am not running any wire directly to the starter. That wire has some major current flowing in it and that is not the way to do this. There should be no reason that we basically cant emulate the car being auto started except the actual key is in, turned to RUN and you press a button to emulate turning the key once more to crank. Its got to be something rather small because i have checked all the necessary wires and they all read as they should as far getting the 12 volts that they need etc. But why the auto starter can supply 12 volts to the yellow wire and start the car but the button cant is what doesnt make any sense.