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Thread: ignition wiring, push-button start

  1. #1

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    Default ignition wiring, push-button start

    So I have a defective lock cylinder and starting my car by touching the BLK/RED wire to the battery got old fast (that's the one coming out of the engine compartment fuse box). At least the ignition worked. Here's how I wired a toggle switch and push-button start for posterity.

    What you need:

    * 3 relays (30-40 Amps) - the kind with 5 terminals, 1/4" wide. (They're easy to find at the junk yard. I used the square ones that say Ford and have the tiny diagram on the side with terminals labeled 85, 86, 87, 87a, 30).
    * Some 12awg wire. I think the primary wires from the battery are 10awg, which will be handy to make those longer.
    * Lots of yellow 10-12awg female quick-disconnect terminals (at least 16)
    * At least 5 really big wire nuts
    * A few self-tapping screws and some 10-12awg ring terminals to fit
    * Electrical tape and shrink tubing to fit your terminals (1/4" I think?)
    * Your choice of toggle switch (I got a nice chrome one with a blue LED from Pep Boys) and push-button switch (I got an all-weather one with a rubber boot, still looking for something sexy) or momentary-toggle switch (the cheap plastic ones from Advance will work.. but you get what you pay for)

    Tools:
    * A steering wheel puller (OEM makes one for $17)
    * A ratchet, short extension, and metric sockets (10mm for the airbag screws, I think, I forget the rest)
    * Some wrenches (my hood latch cable had a 17mm nut and whatever size for your battery terminal ends)
    * Your favorite wire stripper (handles 10awg and smaller)
    * A GOOD CRIMPER is your friend (the heavy one from Harbor Freight that looks like a really big wire cutter with a prong in the middle is actually very good; DON'T use a flimsy version with 3 colored dots that does everything but throw itself away)
    * #2 Phillips screwdriver (you might want a smaller one for the little screws on the clockspring and the ignition switch)
    * A flashlight, better yet a drop light
    * A drill and some bits to drill mounting holes for your switches and start a self-tapping screw

    If things go wrong (more often than not) you'll need:
    * A GOOD voltmeter (not from Home Depot)

    If you've never done electrical work or you make lots of mistakes, find a dry-chemical fire extinguisher. If you smell gas, fix your fuel system BEFORE you do anything electrical. Just sayin'.

    First, disconnect your battery terminal ends. Yes, you'll lose your stereo settings. Do not connect a memory saver.

    Wait 10 minutes. You don't want to play with an airbag.

    Remove the three screws in the bottom of the two halves of steering column trim and remove the trim.

    Remove the airbag. It has two black 10mm bolts in the back side of the wheel. DISCONNECT THE RED PLUG and let it sit in the wheel until you attach your steering wheel puller. Don't let it hang by the wires; lightly pulling is ok, dangling freely is bad.

    Remove the black bolt in the center of the wheel, and attach your puller. Remove the wheel. Hold the wheel and airbag while you unscrew the clockspring (that circular plastic rotating thing); the screws are pretty small and easy to lose. Once the clockspring is off, if you pull the harness out of the white clip beneath the multi-function switches, you can rest the clockspring, wheel and airbag on the driver's seat. I personally couldn't get my airbag disconnected from the clockspring, so that's how I did it. Don't play with the clockspring too much or your horn will get stuck. Very annoying. Also, keep the airbag face down on the seat (not that it will help much). DISCONNECT the clockspring harness.

    Remove the multifunction switches. There's three bigger screws inside the white plastic that attach everything to the lock cylinder assembly. Don't worry about getting the plugs confused; they're all different shapes. Try to remember anyways. Set the multifunction switches aside. Don't lose the screws.

    Now you're looking at the ignition switch. It has a white plastic cover on it that attaches it to the lock cylinder. Remove the little screw. Unplug it from the wire harness beneath the steering column. Clip the little WHT/RED wires for the key-in circuit. Discard with prejudice or bake for 12 mins @ 325. Laugh maniacally.

    At this point you can replace the ignition switch, if you have or obtain a good one. Don't forget to reconnect the WHT/RED wires for the key-in chime (or not). You want to replace the lock cylinder while you're at it, esp. if your key has a hard time going in or won't go in sometimes. To replace the lock cylinder, insert the key, turn it to run, and push in the little brass dot with a probe/pick (it's a locking pin). I've never replaced one on an Escort, so you're on your own.

    At any rate, once you cut the plug off the end of the primary wires, you're at the point of no-return.

    The long dash piece below the steering column just clips in, but there is one small screw on the bottom-right side, facing the floormat. Unscrew that and pull the dash piece out. You'll have to disconnect the plug for the gauge light dimmer too. You should have plenty of room to work on the wiring now.

    The disconnected plug with 4 primary wires and 2 smaller ones has the ignition wiring. The smaller plug with 2 solid black primary wires has power.

    (Don't worry about the colors of the wiring on the ignition switch. You discarded that earlier. Useless trivia: BLK/WHT is ACC, BLK/BLU is START, BLK is BATT, GRN is BATT, BLK/RED is IGN, BLU is IGN)

    Cut the plug off the 2 black primaries and the plug off the ignition wires - that's the one with 4 primary wires and two smaller ones. The smaller ones are the key-in circuit. We're done with them. The 4 big ones are: BLK/RED, BLU, RED/WHT, and BLK/WHT. RED/WHT is your starter wire. BLU, BLK/RED, and BLK/WHT are your ignition wires. They power almost everything that's not high-amps; find some schematics if you're interested.

    There are 5 wire nuts, 2 ignition relays, 1 start relay, 1 toggle switch, and 1 push-button switch.

    Wire colors:
    BLK = black
    BLU = blue
    RED/WHT = red with white stripe
    BLK/RED = black with red stripe
    BLK/WHT = black with white stripe

    Wire Nut 1:
    First BLK primary from harness
    Short length of 10awg to ignition relay 1
    Long length of 12awg to toggle switch pin 1

    Wire Nut 2:
    BLU from harness
    Long length of 12awg to push-button switch pin 1
    Short length of 10awg to ignition relay 1
    Short length of 10awg to start relay

    Wire Nut 3:
    BLK/RED from harness
    BLK/WHT from harness
    Short length of 10awg to ignition relay 2

    Wire Nut 4 (ignition relay power):
    12awg to ignition relay 1
    12awg to ignition relay 2
    Long length of 12awg from toggle switch pin 2

    Wire Nut 5 (relay ground):
    12awg to ignition relay 1
    12awg to ignition relay 2
    12awg to start relay
    12awg to chassis ground (see below)

    Ignition Relay 1:
    Pin 87 - Short length of 10awg from wire nut 1
    Pin 30 - Short length of 10awg from wire nut 2
    Pin 85 - 12awg from wire nut 4 (ignition relay power)
    Pin 86 - 12awg from wire nut 5 (relay ground)

    Ignition Relay 2:
    Pin 87 - Second BLK primary from harness
    Pin 30 - Short length of 10awg from wire nut 3
    Pin 85 - 12awg from wire nut 4 (ignition relay power)
    Pin 86 - 12awg from wire nut 5 (relay ground)

    Start Relay:
    Pin 87 - 10awg from wire nut 2
    Pin 30 - RED/WHT from harness
    Pin 85 - Long length of 12awg from push- button switch pin 2
    Pin 86 - 12awg from wire nut 5 (relay ground)

    For the chassis ground, there's a metal dash support to the right and below where the plug for the gauge light dimmer is. I already had a ground wire attached to it, probably because the last guy had a car alarm or remote starter. Use a self-tapping screw that will fit your ring terminals nicely and drill it in where the dash piece covering it won't interfere.

    I mounted my switches in the little dash trim piece above the steering column, in front of the gauges, that pops out easily. I had to drill 2 holes, one a little bigger than 3/8" for the toggle switch and one bigger than 1/2" for the push-button.

    Before you put everything back together, make sure your airbag and clockspring plugs are disconnected. Also make very sure your parking brake is on or your transmission is in Park! Then, reconnect the positive battery lead. Touch the negative lead to the battery, look, and listen for any sparks or arcing in the cabin. If your toggle switch is on when you hook up the battery, you might hear the seatbelt chime or the blower start and a little arc on the negative battery lead. Bingo. If you don't hear anything, connect your negative lead and go flip that toggle switch, carefully. If nothing happens, give yourself a moment and find some calm and a multimeter. The very first place to check for voltage is Wire Nut 4; you should have power to your relays. If not, check the voltage across the pins of your toggle switch. If, like me, you got a spiffy toggle with an LED and 3 pins, you'll need an extra wire somewhere (it was 2 hours to midnight on New Year's Eve and I didn't have time to do anything but replace my spiffy switch with a normal 2 pin one). If you don't have power at the switch, check for power at Wire Nut 1. If you don't have power there, you might have blown a fuse and you should really recheck all of your connections and fuses, AFTER you disconnect the battery.

    Wrap up all your wire nuts with electrical tape. Use shrink tubing across all your quick-disconnects so they don't short if they ever touch. Wrap all the relays with electrical tape. Leave no connection exposed. Wrap the bottom of the switches with electrical tape. Finally, zip-tie the relays and wiring out of the way (like on the column) and away from the brake pedal. You really don't want to step on this wiring!!

    Put everything back together like you found it. If you mounted switches on the dash piece above the column, you'll have to trim the piece that goes behind the wheel with a cutting wheel, hacksaw, or whatever. Or leave them off until you get around to it. :-)

    What I learned about relays...
    A relay is like a switch that opens when 12V (volts) are applied across pins 85 and 86. To do that, you need 12V on 85 and ground on 86 (or vice-versa, doesn't matter). Pins 87 and 30 are for the higher-amp circuit you want to switch on. Pin 87A is where the switch inside the relay normally rests without voltage across pins 85/86. That's mostly for breaking a normally-on circuit or switching the power from pin 30 between two different circuits (on pins 87 and 87a). These particular relays are versatile. "Why not just use a toggle switch to do this directly?" you ask. Toggle switches are normally rated about 10A (amps) because your finger will be on the device and 10A is enough to stop your heart. If the switch malfunctions and you become ground, your finger may complete the circuit. You don't want 10A or better. Relays are also very reliable. I've suspected many a relay, but replaced only a few very, very old ones (20 years old). Extreme heat, vibration, and time can kill anything, though.

    So, I've driven around this way for a few days now and I haven't had any issues. The MIL is on for my transmission range switch circuit malfunction, but that was on before I did the rewiring. I knew I had a bad ignition switch when I only had 4V on the RED/WHT wire when I turned the key. Gotta replace that range switch before my inspection!

    The only caveat... I still have to use the key to unlock the wheel. So my question is, does anyone know if I can leave the lock cylinder out and not worry about the wheel locking up? At least now I can pull the key out to open the trunk while the car's still running.
    Last edited by rtfm13; 01-03-2011 at 05:23 AM.
    L4FTW

  2. #2

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    Wow... this is a LOT of work for a very simple thing. I did this myself 2 years ago and instead of all that just cut the wires where they plug into the harness (under the wheel) and spliced those. made 1 switch for the ignition (plus a button that I mounted where the "pop-trunk" button was) and another switch controlled all the electronic junk. (Plastic switches with the LED lights - no risk of shock)

    For the wheel lock - on the bottom on the lock cylinder it uses break-away bolts. You just need something like a dremmel to cut slots into them then you can use a flathead screwdriver to take them out. Without the cylinder the wheels wont lock up. BUT do this at your own risk because then you cannot leave your car running with the doors unlocked cause it will just drive away (Yeah I know its self-explanatory but its for the moron who doesn't think of that right off.) When it gets warmer I am going to try again - but I have been off and on trying to figure out how to rewire the alarm so that it will turn on while the car is running, and disable the ignition if it is tripped, but until then I have left my lock cylinder on the wheel.)

    Also - the wire colors can vary from year to year - so you may what to say what the wires do next to their color - i.e. the 2 power(it looks like you are only using 1 power wire? mine are Black and Green), the Radio(Black and White), Starter (Black and Red), Blue (Fuel Pump), & *have it written down as "Clicks" forget what it does atm*(Black and Blue)
    Last edited by KnightJovian; 01-30-2011 at 07:22 PM.
    Quote Originally Posted by dareall View Post
    16 mins is a long time... to wait when Megan Fox says she is horny right now and you're stuck in traffic, 16 minutes is not a long time when it is not your car.

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