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new gm’s with multiplex 2007+

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=133641
Printed Date: December 09, 2022 at 9:23 PM


Topic: new gm’s with multiplex 2007+

Posted By: elway_740
Subject: new gm’s with multiplex 2007+
Date Posted: February 20, 2013 at 9:26 AM

I've installed more remote starts than I can count, however, these newer GM cars such as Cobalt, Cruze, Equinox have become a problem.

I've heard that the ignition output needs to lag by about a 1/4 second behind the GWR or (-) while running wire for the vehicle to start.

The remote starters we install the GWR and ignition energize at exactly the same time.

For some reason these systems work great on the trucks like Sierra, Silverado but the cars have become a real issue.

The guys at Expresskit say we will need to build a time delay relay with a diode, resistor and capacitor on the ignition output to make it lag.

Is this true? Has anyone else ever ran into this issue?

Thank you for any input!



Replies:

Posted By: racerjames76
Date Posted: February 20, 2013 at 9:32 AM
The timing is indeed very important. We use only audiovox and clifford systems for this reason.

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To master and control electricity is perfection. *evil laugh*




Posted By: Chris Luongo
Date Posted: February 20, 2013 at 6:25 PM
Helps to know what kind of remote starter you're installing.

Not everyone will agree with me, but I just hook up ignition and accessory and call it a day. The car will start and run fine without all those resistors.

I've heard rumors that this can leave "soft" codes that won't turn on a check engine light, but that the GM mechanics will see while scanning the car. I haven't confirmed this, though.




Posted By: offroadzj
Date Posted: February 20, 2013 at 8:36 PM
Before the idatalink data modules came out, I always used to do the same as Chris and I never once had a problem. To be honest, I never even installed tach on those since the BCM would take over on accessory drop. But as with him, I couldn't tell you if any of them ever had any 'soft' codes.

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Kenny
Owner / Technician
KKD Garage LLC
Albany, NY 12205




Posted By: Mike M2
Date Posted: February 20, 2013 at 8:44 PM

I never have issues with them using Audiovox. Now there's a better way, use Idatalink RS interfaces. They now have full remote start software that doesn't even need a remote start, you just install the bypass and it does it all right off the factory remote or you can use an optional one button RF.



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Mike M2
Tech Manager
CS Dealer Services




Posted By: Mark Mizenko
Date Posted: February 22, 2013 at 12:35 PM

Ignition, accessory and a key in a box, like Chris said.... however I was blasted on this forum for that method, so I dont give advice on here anymore, but I'll agree with Chris about those resistor wires and the soft codes.





Posted By: digitalcustoms
Date Posted: March 30, 2015 at 11:33 AM
posted_image

You need to slow down the signal in the Ign.1 wire so the acc circuit can power up first on units where the gwr comes on at the same time as acc and ign.




Posted By: howie ll
Date Posted: March 30, 2015 at 11:37 AM
Funny, I've been installing on late UK Astras (same electrics as Cruze), Viper 5X04, no problems.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: digitalcustoms
Date Posted: March 30, 2015 at 11:39 AM
To hotwire a GM with multiplex, you take 2 12v+ wires hold one to acc, then put the other to ign1, and as soon as you power ign 1 drop voltage off at acc and the vehicles computer thinks the key is being turned and sends a crank signal. to remote start acc need to have voltage first, then ign.1 and cut voltage off at acc. the delay circuit posted above slows down the signal in ign.1 1/4 second to let acc fire up first.




Posted By: digitalcustoms
Date Posted: March 30, 2015 at 11:44 AM
[QUOTE=howie ll] Funny, I've been installing on late UK Astras (same electrics as Cruze), Viper 5X04, no problems.


viper units the GWR comes on before the acc and ign1 so it won't need that delay.




Posted By: howie ll
Date Posted: March 30, 2015 at 12:04 PM
Good point.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.





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