WARNING: This page is about a different car, the 2003 Suzuki XL-7 and 2003 Suzuki Grand Vitara. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: DTC B1503 (No. 03): A/C Evaporator Temperature Sensor And Its Circuit Malfunction Troubleshooting Chart (1 of 2)
Courtesy of SUZUKI OF AMERICA CORP.
Fig 2: DTC B1503 (No. 03): A/C Evaporator Temperature Sensor And Its Circuit Malfunction Troubleshooting Chart (2 of 2)