Description

Mitsubishi Galant 1990 Wiring Diagram – Factory Pinouts You Can Trust

If you’ve ever stared at a nest of wires under a Galant dash and reached for a cheap aftermarket schematic that shows the wrong colors or leaves out the ABS control unit, you know why I’m writing this. I’ve been turning wrenches since before most of these cars were built, and I’ve seen more fried ETACS units from guesses with a test light than I care to count. This 14-page Mitsubishi Galant 1990 Wiring Diagram is the real deal – a direct copy of the factory document that Mitsubishi techs used. No redrawn garbage. No missing pin numbers. Just raw grid coordinates and circuit paths that actually match the metal.

The manual uses a component location table with figure numbers and grid references like “ABS CONTROL UNIT (2WD) – 7 (A-B 24)”. That means you flip to Figure 7, look at grid A-B/24, and there’s the unit. It’s not a guessing game. You can trace the A/C system (Figure 10), the ABS hydraulic unit (Figure 7), the MPI control unit for both DOHC and SOHC engines – everything from the fusible link box to the power door locks. Page 1 gives you the full menu; after that you drill into each circuit.

Component Locations: Grid Coordinates You Can Trust

Factory wiring diagrams rely on a fixed coordinate system. Each component is assigned a figure number and an alphanumeric grid. For example, the ABS control unit for 2WD lives at Figure 7, A-B 24. The ABS hydraulic unit for 4WD sits at Figure 7, D-E 27. The manual lists 90+ components this way. I’ve used this method on late-80s Mitsubishi chassis, and it saves you from pulling the wrong connector. Aftermarket diagrams throw all the symbols on one page and hope you can read the artist’s mind. This OEM manual doesn’t ask you to guess – it tells you exactly where to look.

ABS System Wiring: What This Manual Covers

The anti-lock braking system on the 1990 Galant came in 2WD and 4WD variants. The wiring diagram breaks out the ABS control unit, hydraulic unit, pressure switch, and power relay separately. Each gets its own grid entry. If you’re chasing an intermittent ABS light, you need the official pinout for the control unit – the manual gives you the connector view and wire colors. You’ll also find the ECS (Electronic Control Suspension) indicators and power relay, which often get tangled with ABS circuits in practice. Having the factory logic for the ABS power relay saves you from chasing a phantom ground.

14 Pages of Pure Signal Path

Fourteen pages sounds slim. But every page in this manual is packed with dense circuit diagrams and connector pin assignments. Compare that to a 500-page aftermarket manual that buries the wiring appendix with 72 DPI scans. The component location table alone covers the A/C compressor relay, condenser fan relays (hi/lo), cruise control diode, defog relay, dome light circuits, door switches, and the fusible link box. You get the MPI control relay for both DOHC and SOHC engines, the diagnostic connector locations (Figure 3, E6 for DOHC, E11 for SOHC), and the entire ETACS control unit wiring. If you need the charge pressure or fuel pump gauge unit (4WD), it’s on Figure 11, B 43. No scrolling through generic diagrams.

Why Factory OEM Beats Aftermarket Documentation

I’ve bought plenty of third-party wiring books. They almost always miss a ground path or swap two wires on the ABS hydraulic unit. Mitsubishi’s original document uses a consistent grid and references actual connector cavity numbers. The aftermarket stuff? They redraw the circuits and introduce errors. This manual is a direct scan of the factory publication – not a reprint from some data aggregator. That matters when you’re probing a 30-year-old harness and the insulation is brittle. One wrong assumption and you’re replacing a $200 ABS module. OEM documentation from AutoRepairManuals is the only source I trust for torque specs and wiring; for the Galant, the same principle applies to these 14 pages.

Does It Cover the Fuel Pump and Cruise Control?

Yes. The fuel pump gauge unit for 4WD is listed at Figure 11 (B 43). The cruise control unit, column switch, and diode show up in Figure 9 (A 33-34). The manual also includes the stop light switch (with and without cruise), the back-up light switch for manual transmissions, and the inhibitor switch for automatics. If you’re troubleshooting a no-crank condition, the starter relay (M/T) is on Figure 1 (D 3). Every circuit path is drawn with Mitsubishi’s standard wire colors and connector views. No interpretation needed.

Get the Right Pinout Before You Probe

You need a multimeter, a good light, and this diagram. Print it out, tape it to the fender, and mark the circuits as you go. Don’t rely on memory or a blurry screenshot from a forum. The factory pinouts for the MPI control unit (DOHC – Figure 2, SOHC – Figure 3) are laid out with pin numbers and signal descriptions. That’s what you need to check injector pulse, ignition coil trigger, or the ECT sensor return. Beginners should start by confirming the battery and alternator circuits on Figure 1. Then move to the ABS system. The grid coordinates make it hard to get lost.

Does this manual include the interior light circuits?

Yes. The dome light, sunroof switch, door switches and lights, and the clock are listed in the component location table (Figure 8 and Figure 11).

Is the ABS wiring different between 2WD and 4WD?

The manual separates them. 2WD ABS control unit is at Figure 7 (A-B 24); 4WD at Figure 7 (D-E 24). The hydraulic unit and power relay follow the same split. You can’t use one diagram for both.

How do I find the diagnostic connector pinout?

Look up DIAG CONN in the table. DOHC engine – Figure 3, grid E6. SOHC – Figure 3, grid E11. The figure shows connector shape and pin assignments.

Can I use this for a 1991 Galant?

No. The 1990 model year has unique wiring for the ABS, ECS, and MPI relays. A 1991 diagram will have different connector positions and sometimes different wire colors. Stick with the year-specific manual. Related manuals: Mitsubishi Galant 1992 Service Manual – Factory Specs & Wiring for later models, or 1998 Mitsubishi Galant Wiring Diagram Factory Manual 36 Pages for OBD-II cars.

Every wiring job on a 1990 Galant should start with this manual. The component location table is the fastest way to identify a relay or module. The grid coordinates let you cross-reference the actual harness without pulling the whole dash. Aftermarket books won’t give you that. Access the Factory Manual from AutoRepairManuals and keep a copy in your tablet or printed binder. For additional background on how factory diagrams are structured, check out Automotive Wiring and Automotive Wiring.