Question about a Universal Bypass module

I recently bought a Universal Bypass module as preparation for my first remote start/alarm installation. Now, the module i got came with an optional yellow wire that is supposed to be connected to the original key sense wire of the car. Now, the manual says that it's optional, which to me can either be installed or not and would not affect the function of the car. But there is a warning saying that the optional yellow wire is supplied to prevent the key sense module of the car to sense two keys at the same time when a key is inserted into the cylinder. I wonder if i really need to hook this yellow wire up or I will just put the by pass module a little farther from the original key sense ring of the car to prevent it from detecting two keys at the same time. Because it was also said that the car can just render both keys unusable when this happen. How far normally is the range for transponder keys? Or should i just hook up the yellow wire so that I won't have any problem at all. Any advice would be appreciated. Thanks.

More info needed. What brand is the bypass and what car are you working with?Certified Security Specialist

Always check info with a digital multimeter.

I promise to be good.

Tell Darwin I sent you.

I've been sick lately, sorry I won't be on much.

I am working on a 97 Cadillac Catera, and the by pass module is from Auto alarm pro which needs a spare key inside (obviously). Ty

Use the RED wire at the fuse box that tests (+) when the key is in the cylinder and 0 when the key is out of the cylinder. You don't need to to turn the ignition switch over, just place the key in the ignition and it will automatically have 12 volts on the RED wire.Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA

the reason that it is listed as optional is that only some vehicles freak out when they "see" 2 keys at the same time.... to be safe it is best to hook it up always, although on many vehicles it may not be necessary.....Kevin Gerry

Certified Electronics Technician

MECP First Class Installer

Owner/Installer

Classic Car Audio

since 1979

thanks a bunch guys.

I have just started the installation of my new alarm and i am trying to find the keysense wire, and as per VelocityMotors' advice I checked the fuse box and to my surprise, it's like 80% of the wires are red and it's so difficult to pull out the fuse box further out so i don't think testing them all is at all possible. Is there any other way I can do it? Would it be one of the wires that connects to the immobiliser module that is mounted at the key cylinder?

we have done a few Cateras and I do not think we ever used a keysense wire.

yup, i decided not to connect the keysense wire. I  thought that I would just make sure that i stop remote start before inserting the key into the cylinder. Remote start is working fine. thanks to everyone.