Cooling Fan Control, Fuel Pump & Pcm Power Relay

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NOTE: Two different types of relay can be used. An ISO micro relay (relay terminals are numbered 1-5), or an ISO mini relay (terminals are numbered 30, 85, 86, 87 and 87A). On ISO micro relays, relay coil terminals are No. 1 and 2. On ISO mini relays, relay coil terminals are No. 85 and 86. See Fig 1 or Fig 2 .

Turn ignition switch to OFF position. On ISO micro fuel pump relay terminals that are numbered 1-5, measure resistance between relay terminal No. 1 and all other relay terminals. Resistance should be 40-120 ohms between terminals No. 1 and 2 and more than 10 k/ohms between terminal No. 1 and all other relay terminals. On ISO mini fuel pump relay terminals that are numbered 30, 85, 86, 87 and 87A, measure resistance between relay terminal No. 85 and all other relay terminals. Resistance should be 40-120 ohms between terminals No. 85 and 86 and more than 10 k/ohms between terminal No. 85 and other relay terminals. On both relays, if resistance is not as specified replace relay. If resistance is as specified, relay is okay. Check associated circuits for possible open or shorts.

Fig 1: Identifying ISO Mini Relay Terminals

Courtesy of FORD MOTOR CO.

Fig 2: Identifying ISO Micro Relay Terminals

Courtesy of FORD MOTOR CO.