# GMC Passlock II Bypassing: Alarms and Remote Starts.



## tulse (Mar 16, 2010)

There are a few really good bypass guides for the GMC Passlock systems. 

Here's one I found:
http://www.readyremote.com/pdf/notes/note113.pdf

But after the cost of relays and the hell that looks like wiring them, is the bypass module from DEI (or other companies) the better way to go:

Amazon.com: Directed Electronics GMBP GM Passlock 2 & Passkey 3 Data Interface: PK3 & Passlock ODBII: Car Electronics

Am I correct that there is NO reason to use the module or bypass if NO remote start will be used?

Anything else I should be aware of when installing an alarm on a 1999 GMC Truck. 

Thanks


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## TwoDrink (Aug 26, 2009)

When doing a remote start I opt for the bypass modules. Getting the resistor value within tolerance can be a pain IMO. On newer vehicles the modules serve many other purposes in addition to remote start bypass (door locks, sliders, heated seats, etc.) On a 1999 I do not feel it is necessary if you're not doing a RS.
Also are you sure you need a passlock bypass? Many trucks up to recent years do not use ignition immobilizers.


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## tulse (Mar 16, 2010)

TwoDrink said:


> When doing a remote start I opt for the bypass modules. Getting the resistor value within tolerance can be a pain IMO. On newer vehicles the modules serve many other purposes in addition to remote start bypass (door locks, sliders, heated seats, etc.) On a 1999 I do not feel it is necessary if you're not doing a RS.
> Also are you sure you need a passlock bypass? Many trucks up to recent years do not use ignition immobilizers.


Thanks, the whole DIY bypass does look like a nightmare. 

It's a 99', so all I've read says yes with remote start. The truck does have a factory security system. It also has the 3-wire harness to the ignition under the steering column indicative of Passlock. 

I just wanted to be sure there is no other reason to use a bypass module other than for remote start.


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## ween (Mar 12, 2009)

you don't need the bypass module for an alarm only install. just the door key disarm wire (light green/black), which can be found at the BCM which is beneath the steering column.
mark


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