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400975 41-8548 Temperature Sensor for Thermo King
The 400975 / 41-8548 Temperature Sensor is a replacement temperature sensor for selected Thermo King transport refrigeration units. It monitors temperature at the designated sensing point and sends temperature information to the refrigeration control system.
Product Description
The 400975 Temperature Sensor for Thermo King, also known as 41-8548, helps monitor temperature inside transport refrigeration systems. Thermo King parts information identifies 400975 as an Ungraded Coil Temperature Sensor for applications such as evaporator coil and return-air temperature sensing.
The sensor provides temperature feedback to the refrigeration controller. This feedback helps the unit maintain the required temperature and manage cooling and defrost operation.
The part is commonly listed under several Thermo King numbers, including 400975, 40-0975, 40-975, 40975, and 41-8548. Other catalog references include 40-0872, 400872, 41-2858, 41-4021, and 41-4012.
The 400975 / 41-8548 Temperature Sensor appears in applications across SLXi, SLX, SL, SB, TS, SMX, KD, TD, MD, RD and T-Series refrigeration equipment. Exact fitment depends on the unit model and sensor application.
Product Specifications
| Item | Specification |
|---|---|
| Product Type | Temperature Sensor |
| Main Part Number | 400975 |
| Common Cross-Reference | 41-8548 |
| Other Part Numbers | 40-0975, 40-975, 40975, 40-0872, 400872 |
| Sensor Type | Ungraded Temperature Sensor |
| Main Application | Coil / return-air temperature sensing |
| Equipment | Thermo King transport refrigeration units |
| Application | Truck and trailer refrigeration |
| Condition | Aftermarket replacement |
| Main Series | SLXi, SLX, SL, SB, TS, T-Series, MD, RD, KD, TD, SMX |
Thermo King catalog information specifically identifies 400975 as an ungraded coil sensor and gives coil/return-air temperature sensing as its primary use.
Main Function
- Measures temperature at the specified sensing point
- Sends temperature data to the refrigeration controller
- Supports accurate temperature regulation
- Helps control cooling operation
- Supports defrost control
- Helps identify temperature-related system problems
Common Replacement Symptoms
A faulty temperature sensor may cause:
- Incorrect temperature readings
- Unstable temperature display
- Difficulty maintaining the set temperature
- Abnormal cooling operation
- Incorrect defrost operation
- Temperature sensor alarm codes
- Intermittent temperature signals
These symptoms can also result from wiring, connectors, or controller faults. Check the complete sensor circuit before replacement.
Thermo King Applications
| Thermo King Series | Common Applications |
|---|---|
| SLXi | SLXi 100, 200, 300, 400, Spectrum and selected Whisper Pro units |
| SB | SB 100, 110, 190, 200, 210, 230, 300, 310, 400 and selected Multi-Temp units |
| SLX | SLX 200, 300, 400, Spectrum and selected Whisper units |
| SL | SL 100, 200, 300, 400, 100e, 200e, 400e, Spectrum |
| TS | TS 200, 300, 500, 600 and Spectrum |
| T-Series | Selected T600R, T800R, T1000R, T1200R and Spectrum models |
| MD | MD-100, MD-200, MD-300 and selected MD-II units |
| RD | Selected RD-I, RD-II and RD-II SR units |
| KD / TD | Selected KD-II, TD-I and TD-II units |
| SMX | Selected SMX and SMX-II units |
| SLXe | Selected SLXe 200, 300 and 400 units |
Public parts catalogs show a broad application range for 41-8548 / 400975. Always check the original part number, unit model and sensor location before ordering.
Cross-Reference Part Numbers
| Part Number | Reference |
|---|---|
| 400975 | Main Thermo King part number |
| 40-0975 | Common formatted number |
| 40-975 | Short formatted number |
| 40975 | Number without hyphen |
| 41-8548 | Common cross-reference |
| 418548 | Number without hyphen |
| 40-0872 | Related catalog reference |
| 400872 | Number without hyphen |
| 41-2858 | Related catalog reference |
| 41-4021 | Related catalog reference |
| 41-4012 | Related catalog reference |
Some catalogs also list 41-8547 alongside this sensor family. Because sensor applications can differ, do not treat every related number as automatically interchangeable.
Similar Thermo King Temperature Sensors
40-0974 / 41-8547
These numbers belong to another Thermo King temperature-sensor group and appear in aftermarket catalogs. Check the application before using them as replacements because the sensing position and application can differ.
41-6538 Water Temperature Sensor
41-6538 serves as an engine water/coolant temperature sensor for selected Thermo King units. It has a different function from the 400975 / 41-8548 temperature sensor.
41-6539 Water Temperature Sensor
41-6539 is another Thermo King engine water temperature sensor. It also differs from 400975 in sensing location and application.
Suitable Customers
The 400975 / 41-8548 Temperature Sensor is suitable for:
- Thermo King parts distributors
- Transport refrigeration parts wholesalers
- Reefer repair companies
- Fleet maintenance companies
- Refrigeration service providers
- Aftermarket refrigeration parts importers
Ordering Information
Please provide the following information before ordering:
- Original part number
- Thermo King unit model
- Unit serial number, if available
- Sensor installation position
- Connector and wire configuration
- Photos of the original sensor when necessary
This information helps confirm the correct replacement.





