Thermador does not have cross reference for old parts.
When I first called my local appliance parts store and
then Thermador in 2008 and gave them the model
number GPS484GG of the appliance and asked for
part # SQ003 (simmer controller) they said that they
did not know of such a part and so it was no longer
made. I trusted them and told my client. My client
called another technician and I wound-up looking like
a fool. In 2008 the internet wasn't as efficient as it is
today. Now you can easily find that the new part
number for SQ003 is 00497234. So I called
Thermador today again just to see if they had
improved along with the internet over the years.
They still don't know what a simmer controller SQ003 is.