www.Remotesandkeys.com

If you have a DEI system but don't have an existing remote to compare to then you can still find a replacement remote.  Look at the receiver (the brain of the system located under the dash, usually on the driver side, it is a plastic box with wires coming out of it) to find the brand and model name.  If you have trouble finding it you can trace the wire from the LED light or valet switch.  It will lead to the receiver module.  Once you determine the brand and model name of your DEI system you can use the System to Remote Reference to determine the correct remote for your system.

If you have an existing remote but can't read the FCC Id you can open it up and look for the Circuit Board Number and find it on the Circuit Board Number to Remote Reference.