Landings

I prefer landing using the GPS/Autopilot way
. But I have a slight problem when I enter the NAV Heading and the ILS frequency into NAV1 ( I do this about 70 miles out) When ATC tell me ''maintain this altitude until established on localizer'' On the autopilot panel I switch from heading to NAV. When I get established onto the localizer the plane lines up perfectly but it does not decsend with the glideslope
Can anyone help???
Thanks takecare, Ace

Can anyone help???

Thanks takecare, Ace
