Wiring Diagrams — Ford F-250 1987-1991

Technical Reference

Member-uploaded diagrams & documents for this generation. AI-classified; community-verified where badged.

Wiring Diagrams

• Ford C115 Connector Pinout - PCM/EEC 42-Pin Wiring Functions Diagram
  This document is a pin-by-pin legend for the Ford C115 connector, listing the function of each of its 42 pins. Powered circuits include pin 1 (power for coils, key-on 20a fuse), pin 8 (power hot at all times, 20a…
• Ford C115 In-Line Connector Pinout - 42-Pin C115F/C115M Circuit & Wire Colors
  This document is a connector pinout reference for the C115 in-line connector pair, showing both the female side (C115F) and male side (C115M) of a 42-pin bulkhead-style in-line connector. Each connector face is…
• Ford PCM Connector C202 Pinout Diagram - Pins 1-34 Wire Colors & Functions
  This document is a pinout diagram and legend for connector C202, the Powertrain Control Module (PCM) connector on a Ford vehicle. The top portion shows a 104-pin connector face with pins numbered 1 through 104 arranged…
• Ford C116 In-Line Connector Pinout - 38-Pin Wiring Diagram (C116F & C116M)
  This document is a connector pinout reference showing the C116 in-line electrical connector pair on a Ford truck: C116F (female half) and C116M (male half). Both connector faces are drawn with all 38 cavity positions…
• Ford C115 In-Line Connector Pinout - 42-Pin C115F & C115M Wire Circuit Chart
  This document is a connector pinout reference for the C115 in-line connector pair, showing both the female (C115F) and male (C115M) 42-pin connector faces with numbered cavity diagrams, followed by pin-to-circuit…
• Ford PCM Wiring Diagram – 4R70W Trans Controls, CMP Sensor, MIL/TCIL Circuits
  This document is a single page from a Ford factory-style wiring diagram (EVTM) showing Powertrain Control Module (PCM) circuits. It illustrates wiring from the PCM to the instrument cluster's Transmission Control…
• Ford F-250 PCM Wiring Diagram - HO2S, ECT, TP & EVP Sensor Circuits (E6)
  This document is one page (E6) of a multi-page Ford wiring diagram set covering the engine control/fuel system sensors. It shows the Powertrain Control Module (PCM, labeled 'SOLID STATE') and its wiring to Heated…
• Ford HO2S #3/#4, IAT & Octane Adjust Wiring Diagram - PCM Pinout (4R70W)
  This document is one page (E5) of a multi-page Ford factory-style wiring diagram set covering the engine control / EEC system. It shows the wiring for Heated Oxygen Sensors (HO2S) #3 and #4, the Powertrain Control…
• Ford PCM Wiring Diagram - Fuel Injectors, EGR/EVR, IAC, VSS & MAF Circuits
  This scan is one page of a Ford powertrain wiring diagram set covering the fuel injection and engine-management circuits. It shows fuel injectors #1–#4 (connectors C164, C167, C168, C161), the EGR Vacuum Regulator…
• Ford Wiring Diagram - Fuel Injectors 5-8, PCM, DLC & Fuel Tank Pressure Sensor
  This is one page (E3) of a multi-page Ford factory-style wiring diagram set covering the engine control / fuel injection system. It shows fuel injectors #5 through #8, each fed by wire 361 (Red) from splice S117…
• Ford F-Series PCM Wiring Diagram - WOT A/C Relay, EVAP Purge & Coil Outputs (E2)
  This is one page (E2) of a multi-page Ford factory-style wiring diagram set covering engine/powertrain control circuits. It shows the Powertrain Control Module (PCM) and its related circuits: the PCM power relay feed…
• Ford Fuel Pump & PCM Power Wiring Diagram - Relays, Inertia Switch, Circuits
  This document is a Ford factory-style wiring diagram (EVTM page) covering the fuel pump and Powertrain Control Module (PCM) power circuits. It shows power feeds labeled 'HOT IN START OR RUN' and 'HOT AT ALL TIMES' from…
• Ford E4OD Transmission PCM Wiring Diagram - MAF, TP, ECT, TCS & BOO Switch (T3)
  This is a Ford powertrain/transmission control wiring diagram (page T3 of a multi-page set) showing sensor and switch inputs to the Powertrain Control Module (PCM). It covers the Mass Air Flow (MAF) sensor, Intake Air…
• Ford 4R70W Transmission Wiring Diagram - TFT, TCC, EPC & Shift Solenoids to PCM
  This document is one page of a Ford wiring diagram set (page references 25-2, 25-5, 25-7 and 30-1 indicate an EVTM-style manual) covering the 4R70W automatic transmission electrical circuits. It shows power feed…
• Ford Transmission Wiring Diagram - TR Sensor, OSS Sensor & PCM Circuits (T1)
  This document is a Ford factory-style wiring diagram (EVTM page) covering the transmission control circuits, centered on the Transmission Range (TR) sensor and the Output Shaft Speed (OSS) sensor and their connections…
• Ford Overdrive Switch Connector Pinout & Wire Colors Diagram (F-250)
  This document is a wiring/connector pinout diagram for a Ford overdrive switch. It shows the switch connector face with numbered pin positions (6 and 4 at the top, 5 and 1 at the bottom) and identifies five circuits…
• Ford PMGR Starter Wiring Diagram - Solenoid, Relay & Cable Instructions
  This document is a wiring instruction diagram for a Ford PMGR (Permanent Magnet Gear Reduction) starter. It illustrates how to connect a PMGR-style starter motor to the vehicle's starter relay (fender-mounted solenoid)…
• 1990 Ford F-250 Center Console Gauge Panel Wiring Diagram - Voltmeter & Outlets
  This document is a hand-drawn wiring diagram (created in a simple graphics program) for a custom center console gauge panel, uploaded to a 1990 Ford F-250 gallery. It depicts two large circular gauges (a voltmeter on…
• Ford PCM C202 Connector Pinout (Pins 35-90) - Circuit & Wire Color Chart
  This document is a connector pinout table (part 2 of the C202 powertrain control module connector, per the filename C202-b.gif) covering pins 35 through 90. For each pin it lists the circuit number, wire color code…