Friday, April 03, 2009

Adventures in hotwiring your car

I had a problem with my Dodge car, the key didn't seem to do anything. Turn it the three clicks, everything comes on, works fine, press it forward to ignition, nothing. Not even a click.

Push start it, and drive it to a local auto shop, where they are equally confounded. Everything looks right and feels right, but it's just not starting.

They pull apart the ignition, and find a broken part, but can't identify it. The part is an assembly that sits between the key lock cylinder (where you put your key in), and the electronic ignition. The part is a combination of rods, metal and plastic, which also has mechanisms for the key lock.

They talk to the local dealerships, and ask for parts diagrams; this part doesn't appear on any diagrams. He calls other local shops and tries to find someone who's heard something about his part. Nothing. Finally, he calls corporate Dodge, and gets someone on the phone who knows what he's talking about. He says the part, while small, never breaks, so it's not offered as a single part. He recommends buying a whole new steering column for $1100.

Car tech calls around, and finds a shop that might have a used column for less expensive. The tech quotes $700 for the part and labor of replacing it.


I talk to a few people, and one of them thinks he can find the part for me, but it'll take a bit. I rent a car (added rental coverage to my insurance), and use it for four days while I wait for nothing in particular.

During those four days, I talk myself up, and figure I can hotwire the thing to get me out of the rental car, and into my happy little car, while I wait on the parts I need to rebuild the ignition properly.

I decide I'm going to pick up the car on Saturday, push start it, drive it to my brother's house (he has lots of tools), and figure out a way to hotwire it.

Saturday rolls around, and my brother and I are picking up the car, they want to charge me to reassemble the ignition/steering column (with the broken parts???). We say no, we'll figure it out. Also, they left the accessory setting on, so the battery is dead. Like, dead dead. Brother has a trickle charger, so that shouldn't be too much of a problem.

We charge the battery for a bit with the cables, and attempt to push start the car. The car refuses. Push starting wasn't a problem when I brought it in, and as we push harder, and longer, eventually culminating in pushing it with the rental car. Nothing. We bypass the ignition by reaching a screwdriver, charged with 12 volts, down to the starter. It turns over a few times, and fails to start. It becomes apparent that something is preventing it from starting.

I dig into the ignition parts, and figure out how the unidentified part fits into the electronic ignition, how the key cylinder fits into the part, and how they all interact. It seems simple enough. The key inserted into the cylinder pushes a plastic rod forward, which protrudes deep into the electronic ignition, which must allow the car to start. Simply turning the ignition, without that rod poking into the electronic ignition, will not allow the car to start. I experiment with jabbing the rod into the ignition, while turning it, with no success. A heretofore unnoticed red light begins blinking, and an odd beeping pattern starts.

It's obvious something's weird. There's some kind of tamper switch or kill switch that's preventing the car from starting. The car knows something's up, and won't start. We tow it to his house, and I start by disassembling the electronic ignition.

The security torx bits my brother has go down to one-size-too-big, and I can't remove the plastic back of the electronic ignition. By now, the point the assembly fits into is getting pretty torn up, I decide to just tear the back off, and buy a new one if I can't get it working.

A knife and some pliers later, I tear off the plastic back, and identify the fragile brush switch which detects the presence of the key as the ignition is turned. I short the switch so the key will always appear to be in the ignition, and try for a start.

The car doesn't start, but it's no longer complaining as it was before. Progress.

The display complains of bad fuses, and I inspect them all, but can't find any burned out. I click the ignition three times, and get the engine codes to look up online. One of the codes is a failure of the chip sensor. I look up some more information, and discover it's not detecting the chip in the key as nearby the ignition. I didn't even know my key had a proximity chip in it...

The deal is, if the car forgot what the code on the key is, it'll be around $150 to get the chip reprogrammed to recognize the key. If the car DIDN'T forget the key, I just need to have it in the proximity of where it usually is.

There is a cylindrical hole where the lock cylinder used to be, so I just jam the key into the hole, where it conveniently fits quite comfortably without falling out (by design?).

With the key crammed into the empty hole, I jam a screwdriver into the electronic ignition, with the key detector shorted out, and try for a start.

The car turns over, and dies.

It works! The battery just needs as proper charge.

I leave it there overnight on the trickle charger, and we test a few things before declaring it successfully hotwired.

Further investigation of the car's key proximity sensor reveals that the key really must be right up in there for it to work. Removal of the key while the car is running results in the engine dying. Pretty robust anti-theft device!

Pictures will follow when parts come in.

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