1970-1974 Challenger, Barracuda & 'Cuda Wiring Harnesses: Under-Dash, Engine, Front Light or Rear? How to Order the Right E-Body Harness

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1970-1974 Challenger, Barracuda & 'Cuda Wiring Harnesses: Under-Dash, Engine, Front Light or Rear? How to Order the Right E-Body Harness

If you own a Challenger, Barracuda or 'Cuda, you already know the electrical system is half a century old. Brittle insulation, corroded terminals and decades of add-ons and quick fixes are behind most of the flickering dash lights and dead gauges. A new harness fixes that, but Chrysler didn't build one harness for these cars. It built several sections that plug into each other, and each one changed by year, model, engine, ignition and options.

This guide covers the 1970 to 1974 Dodge Challenger and Plymouth Barracuda and 'Cuda, the E-body. Everything below comes straight from our supplier's listings. Where a listing leaves a question open, we say so. (Working on a 1968-70 Charger, Coronet, Road Runner or GTX? See our B-body wiring harness guide.)

Step 1: Know which section you're replacing

  • Under-dash harness. It connects to the switches and sensors behind the dash. It also attaches to the engine harness and runs down the side cowl panel to connect to the rear body harness. It's the biggest section.
  • Engine harness. It runs the engine bay: temperature sending unit, oil light or gauge sender, coil power, horn relay and washer pump motor, depending on the harness.
  • Front light harness. It powers the headlights and front lamps. Our supplier lists these for cars that use a separate engine harness, and says the firewall connector can be a single plug or two depending on the model.
  • Rear light harness. It powers everything at the back of the car and connects to the under-dash harness, or on some cars to an intermediate harness.

Before you order, look at your original harness. Our supplier's warning applies to every under-dash harness here: Chrysler often added separate wire assemblies depending on how the car was built, many of those aren't reproduced, and you may need to reuse them from your original harness.

Step 2: Under-dash harness, by year and gauges

The question here is whether your car has the Rallye gauge instrument cluster.

Two notes from the 1970 listings. The fuse box that comes with them is the 1971-73 version, which takes the late-style 3-prong horn relay, and that relay is sold separately. Fuses, map and courtesy light sockets and warning buzzers aren't included. We don't have a verified under-dash harness listed yet for 1971 cars without Rallye gauges or for 1973-74. Ask us and we'll check with our supplier.

With the Rallye dash, the gauge cluster lights run through their own 1970-74 light bar harness (MP900162), which includes four lamp sockets.

Step 3: Engine harness, by engine and ignition

Three questions decide the engine harness: what engine, is it a Six-Pack, and is it still running stock breaker-point ignition or has it been converted to electronic ignition (the listings call this "with ECU," for the electronic control unit)?

Converting a points car to electronic ignition? The electronic ignition conversion harness (MN2197) replaces the point-style engine harness on 1970-72 E-bodies with a B, RB or Hemi engine. It works with any electronic distributor and control unit. You'll also need a 4-wire ballast resistor, the electronic distributor and the control unit.

Got a factory tach on a 1970 big block? The 1970 engine-side tachometer harness for the 426 and 440 (ME8112) is the piece that's easy to forget.

Step 4: Front light harness, by model and year

One thing to check first. The 1970 383/440 engine harness listing (ME1676) says it combines the engine wiring with the primary front-end lighting connections. The front light harnesses below are listed for cars that use a separate engine harness. So before you order an engine harness and a front light harness for the same car, look at what's on yours, or ask us.

Step 5: Rear light harness, by model and year

All four of these are listed for coupes.

We don't have a verified 1971 rear light harness or a convertible version listed yet. Ask us.

The smaller harnesses people forget

  • Heater and A/C, dash side, 1970-73: ME8119.
  • Wiper motor: MD4511 lists the 1970-72 Challenger without the emission control air pump, and the 1970-73 Barracuda and 'Cuda with 2-speed wipers. For 1973-74 cars originally equipped with 2-speed wipers: ME8100.
  • Back-up lamp and neutral safety switch, automatic transmission: 1970-71 E-body: MD4515. 1972-74: MD4517 (not for Hemi cars).
  • Manual transmission, 1970-74: the neutral safety switch lead harness (MD4518), which includes the clutch safety switch lead. Not for Hemi cars.

Quick checklist before you order

  1. Year and model: Challenger, or Barracuda/'Cuda.
  2. Engine, and whether it's a Six-Pack.
  3. Ignition: stock breaker points or electronic.
  4. Rallye gauges or the standard cluster.
  5. Body style for the rear harness (these are listed for coupes).
  6. Pull a panel and look at your original harness for add-on wire assemblies you'll need to reuse.

Not sure which section you need? Send us your year, model, engine and options and we'll match the harness before you order. Or browse our Challenger and 'Cuda wiring harnesses.