Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
A/C-Heater Control Panel
Checking pin voltage or resistance values at the A/C-heater control panel determines whether it is receiving and transmitting proper input/output signals. Measure values between pin numbers or battery terminals specified in A/C-HEATER CONTROL PANEL PIN VOLTAGE SPECIFICATIONS. Unless otherwise specified in table, ignition should be on. All values listed are approximate. See Fig 1 .
| Component/Circuit (Pin No.) | Test Condition (Across Terminals) | Specification | ||||||
|---|---|---|---|---|---|---|---|---|
| Ground (1) | (2) (1-Battery Negative Terminal) | Less Than 0.4 Volts | ||||||
| Front Recirculation Motor (2) | (3) Activate With ISAT (2-1) | 1-14 Volts On; 0 Volts Off | ||||||
| Parking Heater (3) | Parking Heater Off/On (22-3/3-1) | Battery Voltage | ||||||
| Voltage Supply (4) | Ignition Off/On (4-Battery Positive Terminal) | Less Than 0.5 Volt On; Battery VoltageOff | ||||||
| Air Blend Motor (8) | Motor Stationary (8-1) | 1 Volt | ||||||
| SID + Bus (11) | (2) (11-1) | 2.5 Volts | ||||||
| SID - Bus (13) | (2) (13-1) | 2.5 Volts | ||||||
| Blend Air Sensor Gnd. (14) | (2) (14-1) | Less Than 0.1 Volt | ||||||
| In-Vehicle Temp. Sensor Gnd. (15) | (2) (15-1) | Less Than 0.1 Volt | ||||||
| In-Vehicle Temp. Sensor Fan (16) | (2) (16-1) | Battery Voltage | ||||||
| Fan Control Unit Power (17) | (2) (17-1) | Battery Voltage | ||||||
| Fan Control Voltage (20) | No Fan/Full Fan (20-1) | 0 Volts No Fan/5 Volts Full Fan | ||||||
| Rear Recirculation Motor (21) | (3) Activate With ISAT (21-1) | 1-14 Volts On; 0 Volts Off | ||||||
| Voltage Supply (22) | (22-Battery Positive Terminal) | Less Than 0.5 Volt | ||||||
| Air Distribution Motor (23) | Stationary Motor (23-1) | 1-14 Volts | ||||||
| Air Distribution Motor (24) | Stationary Motor (24-1) | 1 Volt | ||||||
| Air Distribution Motor (25) | Stationary Motor (25-1) | 1-14 Volts | ||||||
| Air Distribution Motor (26) | Stationary Motor (26-1) | 1 Volt | ||||||
| Blend Air Motor (27) | Stationary Motor (27-1) | 1-14 Volts | ||||||
| Blend Air Motor (28) | Stationary Motor (28-1) | 1-14 Volts | ||||||
| Blend Air Motor (29) | Stationary Motor (29-1) | 1 Volt | ||||||
| Rheostat (30) | Full Brightness (30-1) | Battery Voltage | ||||||
| Heated Rear Window (31) | Off/On (31-1) | 0 Volts Off/ Battery Voltage On | ||||||
| Air Blend Sensor (32) | At 73°F (23°C) (32-1) | 2.5 Volts | ||||||
| In-Vehicle Temp. Sensor (33) | At 68°F (20°C) (33-1) | 2.7 Volts | ||||||
| Solar Sensor (34) | Lit With Light Bulb (34-1) | 0-0.5 Volt | ||||||
| Solar Sensor Gnd. (35) | (2) (35-1) | Less Than 0.1 Volt | ||||||
| Fan Test Voltage (37) | No Fan/Full Fan (37-1) | Battery VoltageNo Fan/0 Volts Full Fan | ||||||
| ICE (38) | AUTO Mode/ECON Mode (38-1) | Battery VoltageIn AUTO/0 VoltsIn ECON | ||||||
| Heated Rear Window (39) | On/Off (Use Test Diode) | Diode Flashes | ||||||
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.