What fuses power the PCM and fuel pump relay on the 5.8L engine?

Three 20A fuses in the engine compartment fuse box: fuse U (hot in start or run) feeds the PCM power diode, and fuses I and O (hot at all times) feed circuit 37 Y to the PCM power relay and fuel pump relay.

What does the fuel pump relay do according to this diagram?

The diagram callout states it "Directs voltage to fuel pump," with 12V output on circuit 926 LB/O when the relay is energized.

What wire circuit goes to the inertia fuel shutoff switch?

Circuit 238 DG/Y runs from the fuel pump relay output through splice S139 and connectors C202/C185 to the inertia fuel shutoff, shown on page 25-6.

Where does the PCM get its ground connections?

Grounds are shown via circuit 570 BK/W through splice S106 to G101, and 57 BK to G100 and G104 (see grounds pages 10-1 and 10-3).

What circuit supplies relay-energized power to the E4OD transmission?

Circuit 361 R (12V when the PCM power relay is energized) goes through splice S136 to the E4OD transmission, shown on page 30-2, along with circuit 912 W/R.

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Ford Bronco 5.8L Engine Controls Wiring Diagram 25-1 - PCM & Fuel Pump Relay

Ford 25-1 Engine Controls 5.8L wiring diagram with PCM power relay and fuel pump relay circuits

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Engine controls wiring diagram for 5.8L showing PCM power relay, fuel pump relay and powertrain control module circuits.

AI caption August 2018 · Photo 352 of 386

This document is page 25-1 of a Ford wiring diagram set covering Engine Controls for the 5.8L engine. It shows the power supply path to the Powertrain Control Module (PCM), including the engine compartment fuse box with three 20A fuses (positions U, I, and O), the PCM power diode (circuit 175 BK/Y, hot in start or run), the PCM power relay, and the fuel pump relay (both fed by circuit 37 Y, hot at all times). Wire circuit numbers and colors are labeled throughout: 361 R (relay-energized power to the PCM and E4OD transmission), 926 LB/O (to the VIP data link connector and C101), 238 DG/Y (to the inertia fuel shutoff and connectors C202/C185), 570 BK/W and 57 BK grounds through splices S102, S106, S136 and grounds G100, G101, and G104. The PCM is shown as a solid-state module with pin numbers 37, 57, 1, 22, 8, 40, 60, 20, 48, and 24, plus VIP data link connector circuits 209 W/P, 914 T/O, and 915 PK/LB. Cross-references point to Power Distribution page 13-5, E4OD transmission page 30-2, grounds pages 10-1 and 10-3, and pages 25-2 and 25-6.

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Frequently asked questions

What fuses power the PCM and fuel pump relay on the 5.8L engine?: Three 20A fuses in the engine compartment fuse box: fuse U (hot in start or run) feeds the PCM power diode, and fuses I and O (hot at all times) feed circuit 37 Y to the PCM power relay and fuel pump relay.
What does the fuel pump relay do according to this diagram?: The diagram callout states it "Directs voltage to fuel pump," with 12V output on circuit 926 LB/O when the relay is energized.
What wire circuit goes to the inertia fuel shutoff switch?: Circuit 238 DG/Y runs from the fuel pump relay output through splice S139 and connectors C202/C185 to the inertia fuel shutoff, shown on page 25-6.
Where does the PCM get its ground connections?: Grounds are shown via circuit 570 BK/W through splice S106 to G101, and 57 BK to G100 and G104 (see grounds pages 10-1 and 10-3).
What circuit supplies relay-energized power to the E4OD transmission?: Circuit 361 R (12V when the PCM power relay is energized) goes through splice S136 to the E4OD transmission, shown on page 30-2, along with circuit 912 W/R.