On the 430 you still have to switch from GPS to VLOC to get the data out properly. In other words, if you are flying on the GPS and set up and ILS, you have to manually push the CDI button on the 430 when you begin the approach to utilize the LOC/GS. Inversely, after the missed if you are using the GPS to navigate, you must reselect GPS.
Not sure about the 400. The SL30 is VOR/LOC/GS only anyway so you can't switch.
Hope this helps.
Jerry "Widget" Morris
RV 8, N8JL, 3,000+ hours on my 8.
Saint Simons Island, GA. KSSI
PIF 2007 - 2020
I just wish I could afford to live the way I do