2004 chevrolet aveo 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=132538
Printed Date: May 06, 2025 at 6:14 AM

Topic: 2004 chevrolet aveo rear defrost

Posted By: richardsonke
Subject: 2004 chevrolet aveo rear defrost
Date Posted: October 31, 2012 at 10:31 PM

Does anyone know how the rear defrost is turned on and off on the 2004 Chevrolet Aveo? I think it's a latching relay (no timing mechanism - it stays on until you push it again). Does anyone know if I can tap into the wire and signal the relay with either a 12V pulse or a ground pulse? Thanks.

Replies:

Posted By: shortcircuit161
Date Posted: November 01, 2012 at 6:08 AM

Defrost trigger wires are usually either negative pulse or negative latched signal. I couldn't find the wire color for the 2004 but found one for 2006 (unsure how much they've changed):
Blue - Behind defrost relay, bottom of fuse box

You could test the wire to see if it's a momentary pulse or latching.

You would connect the red lead of your multimeter to 12v constant and the Black lead to the suspected defrost wire. Turn the car on and (while watching the meter) press the defrost button and see if the meter shows 12v for a moment and goes back to 0 (pulsed) or if it goes to 12v and stays there thru the duration of the defrost cycle (latched).

Based on that test, you can connect the relay to that wire and set the remote starter to pulse or latched.

Relay could be wired like this -
Pin 85 - 12v fused constant
Pin 86 - to defrost wire from remote starter
Pin 87 - Chassis Ground
Pin 30 - defrost trigger wire from the Aveo
Pin 87a - not used

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Posted By: smokeman1
Date Posted: November 01, 2012 at 6:24 AM

Omega has this listing for the 2004 Aveo

Rear Defrost

DK BLUE (+)

AT SWITCH- 20 AMP LATCHING CIRCUIT

Rear Defrost

DK BLUE (+)

AT SWITCH- 20 AMP LATCHING CIRCUIT

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Posted By: shortcircuit161
Date Posted: November 01, 2012 at 6:37 AM

Thanks very much smokeman1!!

I checked other wiring sites and forgot to check Omega. posted_image

In that case, the relay would change to

Pin 85 and 87 - 12v constant fused at 20amps
Pin 86 - negative trigger wire from remote starter
Pin 30 - Dk Blue defrost wire on Aveo

I love it when a plan comes together. posted_image

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