161-3128 Sealed General-Purpose Relay

Genuine CAT standard miniature relay, primarily used for cab lighting, horns, starter control, and similar applications.

I. Key Specifications

Part Number: 161-3128 / 1613128 (Common Aftermarket Variant: 161-3128X)

Brand: Caterpillar (CAT)

Type: 24V DC Miniature Electromagnetic Relay

Pins: 5-Pin (SPDT - Single-Pole, Double-Throw)

Housing: Fully Sealed / Water-resistant, Dust-proof, Oil-resistant, Vibration-resistant

Material: Copper Alloy Contacts, Carbon Steel Bracket

Standard Pin Configuration:

Coil: 85 (-) / 86 (+)

Common Terminal: 30

Normally Open (NO): 87

Normally Closed (NC): 87a

Typical Applications: Cab Headlights / Work Lights, Horns, Starter Circuits, Cooling Fans, Solenoid Control

II. Compatible Models (Primarily Excavators)

320C / 320D / 320D2 / 323D / 324D / 325D / 329D

330C / 330D / 336D / 345C / 345D / 349D / 365B / 385B

Wheel Loaders: 950G / 962G / 966G / 972G / 980G

Dozers: D5N / D6N / D6R

III. Replacements and Interchangeability

Direct Replacements (Genuine CAT):

140-9378 (12V, 5-Pin; Identical physical form factor, different voltage)

155-7042 (24V; Similar functionality)

Generic Replacements:

Standard 24V, 5-Pin Automotive / Heavy Equipment Relays (Ensure pin configuration matches) Aftermarket Part: 161-3128X (Leading Market Alternative)

IV. Features and Supply

Fully Sealed Design: Suitable for dusty, humid, and oily construction site environments

Silver Alloy Contacts: Excellent conductivity, long service life, and high resistance to arc erosion