[modern] '93 XJS A/C Blowers Kaput?

Hey all,
My “new” 1993 XJS has A/C blower fan problems. I’ve received some great
input on reworking the right side blower that does nothing, but now I’ve
discovered something else. The left side blower (the only one operating)
only blows on high fan speed. It does nothing on low or medium. When I
move the fan speed control knob from off to low, I get a very brief blower
sound that immediately goes away…moving to medium does nothing, and when I
go to high speed, it blows. It makes no difference whether I’m in manual or
climate control mode (left control knob pushed in or pulled out). Does
anyone have any ideas where I should start looking? I’m thinking the right
side blower not working could have something to do with this problem

PS…I understand that this newsgroup is being revamped. Does anyone know
what the new newsgroup for a '93 XJS will be?