Glad to hear about the cabin filter, which reminds me, it's time to do mine.

The cabin temp sensor is that little grill like thing between the switches and the ECC. To remove the temp sensor:
Pull out the radio, no need to unplug it, and balance it somewhere.
Pull out the ECC unit. The first time will be tough! Mine finally popped out and almost landed in my lap.
Put the radio back in.
Reach behind the dash and feel the plastic tube/housing for the temp sensor. There are 2 plastic push tabs at 12 and 6 o'clock, at the very front, push them toward the center of the tube and pull out the temp sensor. Carefully! The temp sensor is very fragile and sticks out past the plastic.
I cleaned mine with a tooth pick.
Carefully put it back, slide the ECC unit back in, done.

Klaus
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1995 854T and 1998 V70R