Description

Mazda RX-7 1987 Wiring Diagram – Factory OEM Specs

If you’ve ever chased a short in an old RX-7, you know the pain of aftermarket wiring diagrams that leave out half the circuits. The Mazda RX-7 1987 Wiring Diagram from the factory is the only source that tells you exactly where each wire goes, what color it is, and what it does. I’ve seen guys spend a weekend chasing a ground that wasn’t even on the printed page – that’s not a repair, that’s gambling. This manual puts an end to that.

Wiring Diagram Coverage: 20+ Systems

This isn’t a simplified sketch. The factory manual starts with a HOW TO USE THIS WIRING DIAGRAM section on page 50-3 that explains the symbols and abbreviations used throughout. Then it breaks down every electrical system: STARTING & CHARGING SYSTEM (page 50-16), FUEL PUMP & SUB-ZERO STARTING ASSIST SYSTEM, COOLING FAN SYSTEM, METERS & WIRING SYSTEM, FRONT AND REAR WIPER & WASHER, HEAD LIGHTS, RETRACTABLE HEADLIGHTS, ILLUMINATION LIGHTS, COMBINATION LIGHTS, STOP LIGHTS – HORN, TURN & HAZARD FLASHER LIGHTS, BACK UP LIGHTS, HEATER & AIR CONDITIONER, WARNING & AUTO CLOCK SYSTEM, INTERIOR AND SPOT LIGHTS, DOOR LOCK SYSTEM, POWER STEERING CONTROL SYSTEM, THEFT-DETERRENT SYSTEM, AUDIO SYSTEM, and the E & I GAUGE COMMISSION.

Every one of those sections has a dedicated schematic. Need to trace the retractable headlight motor circuit? It’s on page 50-50 with the factory wire colors and connector pinouts. I’ve used this on a customer’s 87 RX-7 that had the headlights refusing to flip up – the issue was a corroded ground at the control relay. The factory diagram showed the exact path. Aftermarket printouts had the relay pins swapped.

Does This Manual Cover the Fuel Pump Circuit?

Yes. The FUEL PUMP & SUB-ZERO STARTING ASSIST SYSTEM is detailed. You’ll see the fuel pump relay, the circuit opening relay, the sub-zero starting assist thermoswitch, and the exact wire gauge. The original wiring in these cars gets brittle. If you’re replacing the fuel pump or troubleshooting a no-start caused by a failed pump circuit, you need the factory diagram. Page 50-38 shows the entire path from the ignition switch to the pump.

Check the Fuse & Fusible Link Section First

Before you start probing wires with a test light, open the FUSE & FUSIBLE LINK SYSTEM section. Page 50-32 lists every fuse location, amp rating, and what each fuse protects. It also shows the fusible links – those are the weak spots that often burn out without blowing a fuse. I’ve seen a melted fusible link cause intermittent power loss to the ECU that no scan tool could catch. The manual tells you exactly which link to check and how to test it. Don’t skip this.

Retractable Headlights: Factory Wiring Procedure

The RETRACTABLE HEADLIGHTS section is worth the price of the manual alone. These systems are notorious for failure. The factory schematic (page 50-50) includes the retractable headlight control unit, the motors, limit switches, and the dash switch. If you’re replacing a motor or the control module, you need to verify the wiring order. I’ve seen aftermarket diagrams swap the up and down limit switch wires – that causes the motor to run backward and jam. The OEM diagram is the only correct source.

50+ Pages of Electrical Schematics

The entire manual is 108 pages, with over 50 pages of full-color wiring schematics (the original is black/white but the detail is there). Each schematic is numbered and cross-referenced to the parts index. The manual also includes a PARTS INDEX (ABBREVIATIONS) so you know what every code means – EGI, IG, S/W, etc. If you’re a DIYer working on an 87 RX-7 in your garage, this is the reference you need. The Mazda RX-7 1994 Wiring Diagram is for later models, but the 1987 version is specific to the first-gen FC3S with the 13B naturally aspirated or turbo. The Mazda RX-7 1993 Service Manual covers engine and chassis, but for electrical, stick with the dedicated wiring diagram.

For a deeper understanding of how automotive wiring systems work in general, Automotive Wiring principles are useful, but nothing beats the factory schematic. And if you’re curious about the evolution of rotary engine diagnostics, check the Automotive Industry Overview for context.

Source Validity: Factory OEM vs Aftermarket

This manual is a direct scan of the Mazda Motor Corporation original document. The copyright is 1987, Hiroshimo, Japan. Compare that to a third-party repair manual that redraws the diagrams and introduces errors. On page 50-3, the foreword states: “All information contained in this booklet is based on the latest information available at the time of printing.” That’s real factory data. The Mazda RX-7 1993 Wiring Diagram – Factory OEM Electrical Manual is similar quality. Don’t waste time on photocopied aftermarket versions that miss half the pages.

Is this manual for the 1987 RX-7 only?

Yes – this specific volume covers the 1987 model year RX-7 (FC3S). It includes all systems as listed. While many circuits carry over to 1988-1991, the pinouts and fuse assignments changed. If you have a 1987, this is the exact match.

Does it include torque specs for electrical connections?

No.

The factory torque values for mechanical fasteners are in the service manual, not the wiring diagram. This manual is strictly for electrical troubleshooting – wire colors, connector locations, ground points, and circuit paths. If you need bolt torque, grab the service manual. But if you’re tracing a short or installing an aftermarket stereo in your 87 RX-7, you’ll get the correct wiring pins from this diagram. Stop guessing and start tracing with the original document. Access the Factory Manual now.