Just bought an 08 silverado with no key fob. I looked up the vin decoder and it says the truck had remote start built in it(AP3). Can I buy a key fob for that truck with a remote start button and program it to the truck? would that work?

 

You'll have to have a dealer do it. Probably not cheap.

 

You can buy a remote online much cheaper than you can from a dealer, but you will have to take it to a dealer so he can program it to fit your truck. Your first problem is to get the proper remote for your truck, Since it is a pickuip, it will probably only have four buttons - Lock, Unlock, Remote Start, and Panic. Ideally, it would be good to know the part number of the correct remote so you could search for just that number. A dealer could probably give you that information by looking up your VIN number. The part number is in very small printing on the back of most GM remotes. Hope this helps

 

not sure what the aftermarket uses for theft bypass. You definitely do not want one that requires a bladed transponder key put in a box. A thief can find the box and use the key to steal the vehicle.

You can't just by a fob online and have the dealer program it. the remote start must be unlocked and added to the vehicle build. a code must be purchased from gm...the kit comes with fobs so forget online fobs.
The factory unit cost is comparable to getting an aftermarket remote start kit installed. if the truck is remote start ready, you buy a kit from gm. The install is simple, no wiring. One way kits are just new fobs and a programming code which the dealer uses to program the remote start option into the rcdlr and bcm.

a two way factory remote start adds a new rcdlm and long rang antenna.

the downside to the factory kits is that it will be disabled if the fuel level is low or if the mil is on.

 

If you happen to have OnStar, your smart phone can be used as a key fob. Start it from China if you want to. Uses Cell signal. I hardly ever use my key fob anymore.