A/C Compressor Clutch Relay: Description

WARNING: This page is about a different car, the 2004 Dodge Pickup and 2004 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

The A/C compressor clutch relay (Fig 1) is a International Standards Organization (ISO) micro-relay. Relays conforming to the ISO specifications have common physical dimensions, current capacities, terminal patterns, and terminal functions. The ISO micro-relay terminal functions are the same as a conventional ISO relay. However, the ISO micro-relay terminal pattern (or footprint) is different, the current capacity is lower, and the physical dimensions are smaller than those of the conventional ISO relay. The A/C compressor clutch relay is located in the intergrated power module (IPM) in the engine compartment. See the fuse and relay layout label affixed to the inside surface of the IPM cover for A/C compressor clutch relay identification and location.

Fig 1: Identifying A/C Compressor Clutch Micro-Relay

Courtesy of DAIMLERCHRYSLER CORP.

The black, molded plastic case is the most visible component of the A/C compressor clutch relay. Five male spade-type terminals extend from the bottom of the base to connect the relay to the vehicle electrical system, and the ISO designation for each terminal is molded into the base adjacent to each terminal. The ISO terminal designations are as follows:

30 (Common Feed) - This terminal is connected to the movable contact point of the relay.
85 (Coil Ground) - This terminal is connected to the ground feed side of the relay control coil.
86 (Coil Battery) - This terminal is connected to the battery feed side of the relay control coil.
87 (Normally Open) - This terminal is connected to the normally open fixed contact point of the relay.
87A (Normally Closed) - This terminal is connected to the normally closed fixed contact point of the relay.