Connecting Aux to Climate Control Buttons Pictorial
Printed From: the12volt.comForum Name: Car Security and Convenience - Alarm/Remote Start Pictorials
Forum Discription: Installer submitted Alarm, Keyless Entry, and Remote Start Pictorials from our Car Security and Convenience forum.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=138044
Printed Date: May 01, 2025 at 7:18 PM
Topic: Connecting Aux to Climate Control Buttons Pictorial
Posted By: yellow_cake
Subject: Connecting Aux to Climate Control Buttons Pictorial
Date Posted: December 23, 2014 at 10:44 PM
Sometimes you can get lucky if your car has a (-) trigger wire for the rear defogger, heated seats, etc. But what about other features which don't have a trigger wire?
I'll show you how to tie into the momentary switch of your climate control...
I will be controlling the front window defogger using an AUX channel of my remote starter via a relay.
Here's my climate control (2000 Maxima) taken apart. There's the on/off button for the front window defogger.
Here's the back of the circuit. The contacts of the button are circled. MAKE SURE TO TEST THE CONTACTS USING DMM. It should read no-continuity normally, and close to 0 ohms while button is pressed.
Solder some thin (22-24 gauge) wire onto the contacts. To avoid a poor solder joint, be sure the wires don't move even a fraction while the solder is cooling; I used some "helping hands" to keep them steady.
I used hot glue to secure the wires (prevent strain & vibration on the solder joints).
Rather than using a large Bosch style relay, I'm using a mini circuit board relay to avoid the unnecessary bulk.
Everything is secured using hot glue. I put a mini-connector to make removal of the HVAC control unit easier.
Here's the final look.
I'll show you how to tie into the momentary switch of your climate control...
I will be controlling the front window defogger using an AUX channel of my remote starter via a relay.
Here's my climate control (2000 Maxima) taken apart. There's the on/off button for the front window defogger.
Here's the back of the circuit. The contacts of the button are circled. MAKE SURE TO TEST THE CONTACTS USING DMM. It should read no-continuity normally, and close to 0 ohms while button is pressed.
Solder some thin (22-24 gauge) wire onto the contacts. To avoid a poor solder joint, be sure the wires don't move even a fraction while the solder is cooling; I used some "helping hands" to keep them steady.
I used hot glue to secure the wires (prevent strain & vibration on the solder joints).
Rather than using a large Bosch style relay, I'm using a mini circuit board relay to avoid the unnecessary bulk.
Everything is secured using hot glue. I put a mini-connector to make removal of the HVAC control unit easier.
Here's the final look.
Replies:
Posted By: yellow_cake
Date Posted: December 23, 2014 at 10:47 PM
Posted By: kreg357
Date Posted: December 24, 2014 at 7:31 AM
Great info! 
Another good use for those mini-relays. Even had a coil quenching diode added ( Howard would be very happy ).
There would definitely be an extra charge for that install upgrade.
-------------
Soldering is fun!
Posted By: tedmond
Date Posted: December 25, 2014 at 9:13 AM
Posted By: yellow_cake
Date Posted: December 25, 2014 at 8:48 PM
kreg357 wrote:
Great info!
There would definitely be an extra charge for that install upgrade.
I love the mini relays for low current stuff.
It is time consuming (and potentially risky), so not really an option for 99% of customers... It is nice to have on my own car.
tedmond wrote:
much easier to grab the wire at the SECU where your locks/door pins/faa/fad are.
GREEN/ red (-)
Hi tedmond, the GREEN/ red @ SECU is for the rear defroster...and yes, I connected that as well
Posted By: howie ll
Date Posted: July 29, 2015 at 12:00 PM
Posted By: howie ll
Date Posted: July 29, 2015 at 12:01 PM
Posted By: yellow_cake
Date Posted: July 31, 2015 at 3:28 AM
Posted By: metz35
Date Posted: December 02, 2015 at 5:00 PM