people keep telling me that you can not change it but you can add to it, my code is already 5 digits and people do not explain well how to add to it so if somebody could clearly tell me how to add/ change it l would appreciate it a lot, thanks.

l dont think many people own a '94 Mercury Cougar, you might be lucky waiting for an answer but l Would suggest you look for your Car Manual (usually in the dash) if not try and find on online. If you dont find anything then l think your best bet would be to find a support board directly for cars or more specific Mercury's, and ask them there.

Take it to a mercury dealer and have them reset it.

What they mean by u can not change it is that u can not erase the factory 5 digit code, it is permanent & will always work but u can add another 5 digit entry code to ur vehicle. l think the procedure for ur Cougar is the same as any othe Ford, u enter the factory 5 digit code, within 5 seconds of that push the 1/2 button, within 5 seconds of that enter the code u want to use & then wait 5 seconds, the system should lock & unlock the doors to confirm the module has been reprogrammed.