View CartA reader asked:
“It (the Remotes Unlimited website) lists (part 583-1583) for both an ’03 Silverado and an ’05 Avalanche 1500.
How hard would it be to program for both vehicles?”
This is a very interesting question. The answer is that you should be able to program the same remote for both trucks and use it as a shared remote for both vehicles. Here is why:
When you “program a remote”, several things happen. First, you take a series of actions to put the system control module into programming mode. When in programming mode, the receiver typically first erases all prior stored remote information. This protects you if a former remote was lost or stolen and is out there in someone else’s hands. Then the control module “listens” for signals from compatible remotes. When you push a button on a remote you are programming, the receiver takes note of the signal it receives. That signal has two components. One is a unique stream of information that is always part of the signal from that remote and that identifies the specific remote. The second component is a coded signal that varies each time you push a button on the remote. This “rolling code” (component of the signal) is one in a sequence of a very large number of codes that were initially randomly generated and stored in both the remote and the receiver. In programming, the receiver makes note of the unique code that identifies the key fob and the rolling code that tells the receiver from where in the long list of stored codes the new remote is currently transmitting. If you are using more than one remote with the vehicle, you then push a button on the second remote and the receiver stores that remote’s unique code and rolling code. Most keyless entry systems can store information for anywhere from 3 to 8 different remotes. The important thing to note for answering your question is that nothing happens to the remote. All of the information storage that occurs during programming is happening in the control module located in the vehicle. That is why you should be able to program the same remote to work with two different vehicles that used the same system.
There are a couple of issues with doing this though. One you have probably already thought about. That is, if both vehicles are nearby when you push a button on the shared remote, you will be unlocking or locking both vehicles.
A second issue is less obvious. Remember that the remote is transmitting a signal that varies each time a button on the remote is pushed. Once a remote is programmed to work with a vehicle, the vehicle’s system does not accept just any rolling code signal from that remote. It is specifically looking for a code that matches one in the set of stored codes “downstream” from the last valid code it received. This is a security feature to prevent a “signal thief” from recording the signal transmitted this time and replaying it to activate the system at a later time. Keyless entry system designers anticipated that a button could be pushed inadvertently in your pocket or before you are close enough to the vehicle for the signal to be received. So, the receiver does not just look for the very next code in the list, it checks to see if the code is anywhere in a larger set of, say, a hundred codes that follow the last code it received. The reason this could be an issue is that, if you used your shared remote with one of the vehicles exclusively for a long period of time, the signal being sent by the remote could have advanced far enough in the set of stored codes to no longer be among the codes being “looked for” by the receiver in the other vehicle. Then, you would have to re-program the system to accept that remote all over again.
