2003 chevy malibu rear defrost
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=135834
Printed Date: May 14, 2025 at 5:14 AM
Topic: 2003 chevy malibu rear defrost
Posted By: jnz1
Subject: 2003 chevy malibu rear defrost
Date Posted: January 14, 2014 at 10:08 PM
Anyone know what wire on a 2003 Chevy Malibu activates rear defrost?
Replies:
Posted By: powerslave
Date Posted: January 14, 2014 at 10:24 PM
You can tap one of your alarm AUX outputs that has a momentary pulse, and splice it into the switch wire. When you press the remote start, there are a lot of options you can use. People use those AUX outputs to turn on their seat heaters too.
Or, if your doors lock on remote start, you can bridge a wire from the lock pulse wire to the button too.
Adjust for correct voltage if needed. The defrost button may not be a 12V trigger, but you can check that with a mufti-meter.
Posted By: jnz1
Date Posted: January 20, 2014 at 1:39 AM
The alarm puts out an -200ma output for the defrost. The hvac has multiple plugs on the back none I can tell just by looking for the defrost button. How can I test for. This?
Posted By: jnz1
Date Posted: January 21, 2014 at 9:19 PM
To answer my own question DMM Test Reading should read
12volts then when you push it and drops to 0v and stays there. This is called a (-) latching defroster.
12volts then when you push it drops to 0v then jumps back to 12volts. This is called a (-) pulsed defroster.
0volts then when you press it jumps to 12volts. This is a + latched defroster and requires a relay to switch polarity and increase your amperes.
Posted By: tedmond
Date Posted: January 23, 2014 at 11:15 AM
white (-) latched @ hvac control.
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Ted
2nd Year Tier 1 Medical School
Still installing as a hobby...pays for groceries
Compustar Expert
Posted By: jnz1
Date Posted: January 24, 2014 at 3:44 PM
Thanks
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