2004 chevrolet aveo rear defrost

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.

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

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

When all else fails, Read the Instructions

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Thanks very much smokeman1!! I checked other wiring sites and forgot to check Omega. 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.