corning model 0-24BT serial 60 44212224

I have been having issues with it not running. Tested to door switches - Good. Replaced the timer - pointless because that wasn't the issue. Tonight I decided to turn the dishwasher on its back to check out the bottom. Plugged it in to test and it started to run?! Tipped that bad boy upright and ran a test cycle, started without issue, but stopped midway through before the rinse cycle. Couldn't get it to turn back on. Flipped it into it's back and it turns on again. Why would turning it on the side make it run but print it back upright cause it to crap out again? My current options... Put the old timer back in, return the replacement, buy a new pump. Find out why the pump isn't working when it's upright. Buy a used built-in dishwasher and fit it into the cabinet of this one. (This last option worries me. Will it work?) A brand new portable is outrageously expensive compared to what you can buy for a built-in. I'd love to buy a new built-in and stick it into this cabinet, but that'll have to wait til I have the money to do so. Model: GSC3500R20WW If anyone needs any pics, lemme know. Thanks in advance for the help ​