
1. Heater control unit

| Pin No | Connector A | Connector B |
| 1 | Driver's mode control actuator feedback | Sensor ground |
| 2 | Intake actuator feedback | ECV (-) |
| 3 | Passenger's temperature control actuator feedback | ECV (+) |
| 4 | Driver's temperature control actuator feedback | - |
| 5 | Auto defogging actuator feedback | - |
| 6 | - | FET DRAIN feedback |
| 7 | - | Blower motor (+) |
| 8 | Photo sensor (-) LEFT | Blower INH |
| 9 | Photo sensor (-) RIGHT | Blower IS |
| 10 | - | Blower PWM IN |
| 11 | DEFOG DATA | - |
| 12 | DEFOG SCK | - |
| 13 | DEFOT TEMP | Sensor (+ 5V) |
| 14 | Ambient temperature sensor (+) | FET (GATE) |
| 15 | Evaporator sensor (+) | - |
| 16 | - | Battery (+) |
| 17 | - | Ground |
| 18 | - | - |
| 19 | - | - |
| 20 | - | - |
| 21 | Driver's mode control actuator (Vent) | - |
| 22 | Driver's mode control actuator (DEF) | - |
| 23 | Intake actuator (FRE) | - |
| 24 | Intake actuator (REC) | - |
| 25 | Passenger's temperature control actuator (Cool) | IBU ACTIVE (Low) |
| 26 | Passenger's temperature control actuator (Warm) | - |
| 27 | Driver's temperature control actuator (Cool) | - |
| 28 | Driver's temperature control actuator (Warm) | - |
| 29 | Auto defogging actuator (Open) | Blower relay |
| 30 | Auto defogging actuator (Close) | LIN |
| 31 | - | IGN1 |
| 32 | - | IGN2 |
| 33 | PTC relay1 or 2 | |
| 34 | CAN FD (Low) | |
| 35 | CAN FD (High) | |
| 36 | - | |
| 37 | LOCAL CAN (High) | |
| 38 | LOCAL CAN (Low) | |
| 39 | PTC ON signal | |
| 40 | Ground |
1.Disconnect the battery (-) terminal.
2.Remove the glove box.(Refer to Body (Interior and Exterior) - "Glove Box")
3.Press the lock pin (B) and then remove the crash pad under cover (A).

4.Disconnect the blower motor connector (A).

5.Remove the heater control unit (A), after removing the screws.

6.Disconnect the heater control unit connector.

7.Install in the reverse order of removal.
• Make sure the connector is connected properly.
Heater & A/C Control Unit (DATC)Hyundai Tucson (NX4) 2022-2026 Owner's Manual: Scheduled Maintenance Services
If any of the following conditions apply, follow the Maintenance Under Severe
Usage
Conditions.
Repeated driving short distance of less than 5 miles (8 km) in
normal temperature or
less than 10 miles (16 km) in freezing temperature
Extensive engine idling or low speed driving for lon ...
Hyundai Tucson (NX4) 2022-2026 Owner's Manual: Master warning light
This warning light illuminates:
If a malfunction is detected in any of the
following:
Forward Collision-Avoidance Assist
malfunction (if equipped)
Forward Collision-Avoidance Assist
radar blocked (if equipped)
Blind-Spot Collision-Avoidance Assist
malfunction (if equipped)
Bl ...