Arnott RH-3999 Headlight Level Sensor - Rear

Arnott RH-3999 Headlight Level Sensor for Tesla S

Arnott RH-3999 is a new rear headlight level sensor for Tesla S models with air suspension leveling control. It measures chassis-to-road distance and sends that input to the ECU so the suspension system can adjust ride height as needed.

Built as a standard-grade replacement, this sensor addresses wear from road debris, water, salt, and impact damage. It is a direct-fit service part for rear-position applications on 2012-2016 Tesla S vehicles, including the 2016 Tesla S rear with a 4-pin connector.

Key Features

• Brand: Arnott
• Part number: RH-3999
• New, standard-grade replacement sensor
• Rear position application
• 1 female oval connector
• 4 male terminals
• Connector color: various
• Terminal type: pin
• Mounting hardware not included

How It Works

The RH-3999 headlight level sensor reports suspension height changes to the vehicle control system. That signal helps the ECU command the air suspension compressor to raise or lower the air struts and maintain proper vehicle leveling. For Tesla S owners, accurate sensor input is important for consistent ride height control and suspension performance.

This part cross-references 100417300A for the same application. If you are replacing a worn or damaged Tesla S rear ride height sensor, RH-3999 provides the correct electrical and mounting configuration for the listed vehicles.

Common Problems It Can Address

• Suspension height readings that are inaccurate or inconsistent
• Rear ride height control faults on Tesla S models
• Warning lights related to leveling sensor performance
• Damage from road debris, water, or salt intrusion
• Wear-related sensor failure in the air suspension system

Installation Notes

Verify connector style, terminal count, and rear-position fitment before installation. This sensor uses a female oval connector with four pin terminals, and the 2016 Tesla S rear application notes a 4-pin connector. Inspect the linkage and mounting points for corrosion or damage before installing the new sensor. After replacement, confirm proper ride height operation and clear any stored suspension codes if required by the vehicle.

Quality Assurance

Arnott supplies this RH-3999 sensor as a new aftermarket replacement for Tesla S rear leveling applications. It is built to replace a worn ride height sensor and restore accurate suspension input to the ECU.