How To: Install a Starter Kill Relay - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
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post #1 of 4 (permalink) Old 07-09-2012, 01:36 PM Thread Starter
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How To: Install a Starter Kill Relay

This how-to will walk you through installing a starter kill relay in a cobalt.
1 - 5 post relay
1 - on/off switch
2 strips of about 3-4ft of wire, preferably 14g to match stock (wire length depends on where you want to mount your relay)
basic electrical tools (wire strippers, test light, soldering iron, electrical tape, possibly crimps and connectors for the relay if yours isnt prewired)

Step 1:
Locate the starter wire under the hood. Its a light purple/violet color and is 14g so its thicker than the rest. Find it, test it. It will be negative at rest and positive when cranking. Once you know thats the right wire, cut it.

Step 2:
Feed your 2 lengths of wire threw the firewall to the start wire. If the wires are identical, mark one with a marker on each end so they can be identified later. Save these wires for later.

Step 3:
Open drivers right kickpannel (easiest to remove the white mount as well) Locate the large connector under the radio area, find an ignition wire. It is the only yellow wire that I could see on mine, but test it. Its rather skinny, maybe 24g wire. Connect this ignition wire to one of the wires going through the firewall. I labelled mine previously with a (+) since IGN is 12v+.

Step 4:
Wire and mount your switch where you want it. Note that it will be a ground wire trigger so you have a great deal of options of where you want it. Ground one side and run the other side to the 2nd wire going through the firewall.

No Pictures, mines controlled by may alarm, not a switch

Step 5:
Connect your relay to your cut starter wire using pins 87a and 30. I put 30 on the fusebox side and 87a on the engine side.

Step 6:
Wire the relay!
Pin 87 is unused
Pin 87a is youre engine side starter wire
Pin 30 is youre fusebox side starter wire
Pin 86 is youre ignition wire
Pin 85 is youre switch/trigger wire

See google for a pic

Step 7:
Clean everything up and test your new starter kill. Engaging the switch will "cut" youre starter wire making it impossible to start the car. Flip the switch off and you get a connected wire at rest and the car starts.

****NOTE**** You MUST have the relay close to the starter wire or there wont be enough power to turn over the starter. Trust me, I had to redo mine when I had the relay inside the car.

Good luck!

Last edited by acoutu; 07-09-2012 at 03:08 PM.
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post #2 of 4 (permalink) Old 07-09-2012, 01:44 PM
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Nice! My buddy did this and one to his fuel pump. If you dont think he is parinoid he also has a clutch bar and an alarm system that got set off by a near by firework a couple weeks ago! Never been stolen though!

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post #3 of 4 (permalink) Old 07-09-2012, 02:01 PM
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Wish they'd steal mine, I'd get an SS SC sedan like that yellow one that was for sale on here. Why not just bypass the crank fuse or BCM fuse in trunk instead of cutting wires. Why go through the fire wall with wires when you could intercept Run crank voltage @"D3" of connector "C4" right there behind the BCM.(yellow wire) You wouldn't even need a relay unless you put in an alarm. Excuse me if I don't get it, but you know I'm curious.

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Last edited by Coby7; 07-09-2012 at 02:27 PM.
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post #4 of 4 (permalink) Old 07-09-2012, 03:18 PM Thread Starter
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My insurance company pays a good chunk of the deductible (they might not even charge it if I remember right) if they steal the car itself and can bypass an immobilizer and starter kill. And that just how Ive always done starter kills...just cobalts dont have a starter wire at the ignition where i'd usually install it.

Beside, if someones going to go through all the effort to try and steal my car, they might as well get to listen to some music until I realize whats going on and meet them with a baseball bat.

Also, if I do a bypass cutting power to the BCM, I may have some issues with the alarm or have codes thrown. If thats what you meant. This starter kill is triggered every time the alarm goes off, and on a switch, its every time you set it, so probably every time you leave the car. That much rebooting of the BCM couldn't be healthy for it.

Actually a switch or relay that "cuts" that yellow wire I used and you pointed out would do the same thing yes

Last edited by acoutu; 07-09-2012 at 03:20 PM.
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