no range on prostart

i put a remote start in my buddies pick-up, a 2003 duramax full load, everything works great but the range is terrible, he tried a complete new system with the same result. what happens is if you go right up to the trk and start the trk on remote than shut it off, his range is way better, but after about a 1/2 hour the range is gone again. some one told him the frequency has to be change with a modual. does anybody know about this issue and how to fix it. thanks for your time.billybob

I agree with jamesbond007. In 2003 GM changed the operating frequency of the keyless entry in the trucks as they did a few years earlier in the Sunfires and Cavaliers. You need a kit which works on 433 Mhz. Many of the correct systems will actually have 433 embossed on the antenna.sparky

thanks guys, that is exactly what is wrong with it, 12volt rocksbillybob