Found pressure switch tubing chewed up causing pressure switch to not be pulled in. Removed chewed up part and put it back on. System started up and started to heat. Blower has a lot of build up and has a weak capacitor. Both of these will cause the motor to fail. While I’m crawl notice all of ducting has holes chewed by some sort of rodent. Plenum also is in very poor shape. 4 inch flex has come off the system. Gas line is against code. Condensate pump is old and needs to be replaced. Plenums need to be replaced. Highly recommended having install supervisor out to give quote for new system and duct work. Customer agreed to have them out for quote.