keyless remote working on my truck and car

[davidj]

well I was trying to do a nice thing and really didnt think this one through...... my brother just picked up an 03 mustang gt this weekend and it didnt come with the keyless entry remote... so I thought that maybe I could program my remote from my 99 f250 7.3 to work with his mustang gt and then see if it worked before he dropped coin on a ebay remote... so then I tried to program it back to my truck and it is still working on both cars at the same time. this is a problem because my truck and his car share the same driveway so I end up unlocking his car when I unlock my truck. What can I do about this? tell me there is an easy fix please!

[wiyrs]

dunno about factory steps to do it, but u have to erase the codes from his "Brain"
and btw autozone sells keyless entry FOBS for factory alarms. i paid like 50ish$ for a new fob for my dads 96 f250. came with instructions too