Since the brushes have been replaced, check the bar fuse near the master cylinder. Don't simply look at it, nudge it gently to see if it is separating at the ends. Sometimes it will stress crack and look like it is making contact, but will do so eratically.

If you are CONVINCED that this fuse is SOLID, then do a search and find the posts that have to do with climate control diagnostic. Use an LED and a jumper wire to see if there are any diagnostic codes stored by tapping at the diagnostic connector near the battery.

Good luck,