Ignition Fuse Blowing After Alarm Install
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=71241
Printed Date: July 23, 2025 at 8:49 AM
Topic: Ignition Fuse Blowing After Alarm Install
Posted By: baff2004
Subject: Ignition Fuse Blowing After Alarm Install
Date Posted: January 21, 2006 at 8:02 PM
Hey All, A friend and I just installed a Code Alarm CA-135/425 alarm on my 99 Tacoma. Everything seemed to be working fine until we went to start the car. It turns over, but will not start. We check the fuse box to find that the ignition fuse was blown. We put a new fuse in and tried it again, blew the fuse as soon we tried to crank the engine over again. We have tried lots of different things, but can't seem to find out what the problem is. Any help would be greatly appreciated!
Replies:
Posted By: Powermyster
Date Posted: January 21, 2006 at 8:10 PM
double check your connections and check ingition wires where you made them make sure they are not exposed or touching the chassis
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Why oh Why didn't i take the blue pill
Darren Power
Posted By: dualsport
Date Posted: January 21, 2006 at 9:07 PM
Yeah, look carefully at the connections you made to the ignition line and see if you might have something crossed up. You might try using a headlight or something similar during your testing instead of putting a fuse in the block, to avoid repeatedly blowing more fuses. Connect it to the terminals of the fuse block, and see if it goes full bright when you crank; if it does, then your problem is still there.
Probably start with disconnecting the alarm module from the harness and see if that changes anything.
Might have more ideas if you sketch out the connections you currently have attached to the ignition and starter circuits.
Posted By: Powermyster
Date Posted: January 22, 2006 at 5:34 AM
the headlight won't be able to handle the current on an ignition circuit. plus it would light anyway being in series with ant other equipment on the circuit
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Why oh Why didn't i take the blue pill
Darren Power
Posted By: dualsport
Date Posted: January 22, 2006 at 9:21 AM
That's true, but the idea isn't to run the car, just identify if the shorted condition still exists while troubleshooting, without using up a stockpile of fuses.
There's apparently a short that only occurs when he engages the starter, so there should be a visible change in the brightness of the light when trying to crank. If things are back to normal, it should remain the same.
Posted By: baff2004
Date Posted: January 22, 2006 at 3:09 PM
Thanks for the info guys, i'm going out now to see what I can do to fix it. I'll let you know what happenes. Thanks again!
Posted By: Powermyster
Date Posted: January 22, 2006 at 3:37 PM
i think i know what you mean now dual.. you don't want him to turn on the igntion circuit just crank the starter without ignition
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Why oh Why didn't i take the blue pill
Darren Power
Posted By: baff2004
Date Posted: January 23, 2006 at 6:43 PM
Hey guys, I went through and checked all the wires, redoing all of them. I moved the ground, and the alarm seems to be working fine except for one little problem. Now, each time I arm the alarm and then it goes off, the ignition fuse blows. I narrowed the problem down to the parking lights. Whenever the parking lights are activated by the alarm, the ignition fuse blows. I temporarily cut the wire for the parking lights and everything works fine. I check the connections and I don't see any signs of a short, and I know the right wires have been tapped. Any ideas on that would be great! Thanks in advance...
Posted By: OhioMike1101
Date Posted: January 23, 2006 at 7:01 PM
does the alarm have a (-) output for PK and you hooked to the (+) by chance or vice verse.
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South Side Audio
2501 S. High St
Columbus, OH 43207
Posted By: dualsport
Date Posted: January 23, 2006 at 9:00 PM
Out of curiousity, what is the value of the fuses you're using for your alarm power and for the ignition?
Does sound like something's crossed up like OhioMike said-
Posted By: baff2004
Date Posted: January 24, 2006 at 1:57 AM
The alarm does have both + and - for the parking lights, and I'm positive I have them hooked up correctly. If I hook them backwards, they don't work at all (but the alarm still works). As for fuse size, the ignition fuse is 7.5, but I've tried up to a 15 and it blows that right away. The alarm power has a 30 amp fuse on it. Like I said, I checked all the wires and can't seem to find a problem. Maybe there is something else I should be checking? Thanks for all your help guys!
Posted By: dualsport
Date Posted: January 24, 2006 at 5:44 AM
Shouldn't ever bump up fuse values to try to fix the problem; that defeats the purpose of the fuse, risky-
So are you using the (+) output for the parking lights?
You should check each side of the connection separately to isolate the problem-
Put a test light on your alarm's parking light output and make sure it lights up as you expect when you activate the alarm; basically substitute the test light for the car's parking light connection.
Though you're positive you have the right wire, check it again by measuring the voltage at the spot you tapped in for the parking lights, and see if goes high and low when you turn the lights on and off manually. If it looks okay, you could try applying power using a fused wire to the connection and see if the lights come on-
If they work normally that way, see if you can measure the current to see if it's a direct connection to the parking light circuit or maybe relay controlled.
Are you getting the alarm power from a independent line from the battery or are you tapping in at the harness somewhere? If everything works in the tests above, the difference is the amount of load between the test light and the parking lights, and maybe that's a factor-
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