Upon arrival customer explained that fire alarm company was out recently to run tests and found 4 out of 6 AHUs weren’t shutting down when AHU shut down is pressed. Units 3.2, 2.1, 2.2, and 2.3. I have spoken to customer about this in the past but we haven’t been able to resolve yet. During diagnosis I found unit 3.2 smoke alarm was disconnected. Had to rewire power source from transformer, change control wiring from blower, then rewire safety devices because low temp sensor had failed. Tested operation and made sure thermostat and blower shut down when fire alarm or smoke alarm go off. Quoting to replace bad low temp coil sensor. Then found Unit 2.1 needed thermostat power source changed as well. Rewired Blower contactor and removed Relay from zone panel. Tested system and thermostat and blower shut down when alarm is triggered. Found 2.2 and 2.3 needed to be rewired so smoke alarm break R wire to thermostat. Tested both, went back and tested all 4 again. Called customer because h