I'm sorry because I referred you to a wrong Service manual which is for a newer models. Finally I found the right Service manual
and hopefully it'll help you better.
The first thing I would do is check all connections in the junction box according to the installation instructions from the Service manual. It is very important and I've seen many mistakes done by installers.
Then check if the control board and the key board are properly connected as it's shown on the picture (page 3-3).
Perform all troubleshooting as recommended in the Service manual. Post the results.
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