163-6703 (CAT) 24V Off-Delay Relay / Timer Relay

Genuine CAT off-delay relay, designed to delay power cutoff after the engine is shut down (75 seconds), thereby protecting electrical circuits and equipment.

I. Core Specifications

Part Number: 163-6703 / 1636703

Type: 24V DC Off-Delay Timer Relay

Delay Time: 75 seconds (Fixed delay; power cuts off 75 seconds after engine shutdown)

Interface: 4-Pin DT Connector (Plug with lead wires)

Mounting: Dual-bolt fixing (M6 screws)

Housing: Fully sealed—waterproof, dustproof, oil-resistant, and vibration-resistant

Function: Delayed power cutoff after engine shutdown (Controls power supply to the cab, ECM/computer board, solenoid valves, etc., cutting power after the delay period)

II. Applicable Models (Primarily Excavators)

311C / 312C / 314C / 315C / 318C / 319C

320C / 320D / 321C / 322C / 325C / 330C

345C / 365C / 385C, as well as select D-Series models

Compatible Engines: 3066, 3126B, C6.4, C7, C9, C13, C15, etc.

III. Replacements and Interchangeability

Direct Genuine Replacement:

111-4870 (Identical function, interface, and delay time)

Aftermarket Replacement:

163-6703X (Mainstream OEM-style aftermarket version)

⚠️ Note: This component cannot be replaced by a standard relay; it *must* be replaced with a 24V off-delay type with a 75-second delay. IV. Function and Failure Symptoms

**Primary Functions:**

Delays power cutoff by 75 seconds after the engine is shut off.

Protects the ECU, controllers, sensors, and solenoid valves from the shock of sudden power interruption.

Prevents data loss, circuit damage, and equipment malfunctions.

**Common Failures:**

Immediate power cutoff upon engine shutdown; equipment error codes; data loss.

Excessive or insufficient delay duration; failure to start; battery drain.