Our 2004 Bosch dishwasher has two issues.
1. Self test E1 code indicates a heating issue. A couple years ago it sometimes wasn't cleaning dishes well and left residue or grease on them. I took apart the door, inspected the control module and found no burnt or cold solder joint issues, and reassembled it. After that, it cleaned well 80% of the time but sometimes left white residue (minerals? soap?) on dishes. Regular wash started taking a long time, 2hrs plus with it getting stuck with 30 or less minutes left. As of last week, it's no longer washing well at all and leaves grease and such on dishes.
2. When starting a wash, it now seems to finish quickly, drain all the water out, and then the drain motor keeps running even though there's no water visible in the dishwasher. I've cleaned the filters, inspected and cleaned the impeller for the drain on the left, and used my fingers to check the right side (fill?) impeller and it doesn't feel like there's anything stuck there.
Is it likely the control board is bad even though it visibly looks okay? I hate to spend $169 on a new board without evidence it's the root cause.
Where should I start looking to fix the drain motor issue?