91 MX6

The problem I have with MX automatic trans is the hold light and drop
down 1 gear function wants to activate and deactivtre on it own. If I
keep shutting it off I will occasionally get an engine stall but it
starts right up again with no hesitation or long cranking.
I,m thinking trans control module. Does any one have a suggestion or
source of transmission repair manual and circuit drawings for a 91 MX6
Turbo.
Cheers
Harry