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Peterbilt 357 A/C Compressor Connectors

Peterbilt 357 A/c compressor connectors

Starting at $7.95, AutoBuffy stocks 2 A/C compressor connectors from Standard Ignition for the Peterbilt 357. This small wiring connector links the compressor clutch coil to the vehicle's electrical system, signaling the compressor to engage. When it corrodes, burns, or breaks, the A/C stops working entirely — and the fault is often misdiagnosed as a failed compressor.

Signs your Peterbilt 357 needs a new A/C compressor connector

  • A/C blows only warm air and the compressor clutch never engages, even when the system is fully charged
  • Intermittent cooling that cuts in and out, especially after the engine bay heats up
  • Visible burn marks, melted plastic, or darkened terminals on the connector body
  • Corrosion or greenish-white buildup inside the connector pins, causing high resistance
  • A/C clutch relay and refrigerant level both check out fine, but there is still no power at the clutch coil
  • Diagnostic trouble codes related to the A/C clutch circuit, such as an open or short in the compressor control circuit

Which A/C compressor connector should you buy for your Peterbilt 357?

The main decision is whether to buy an OE-spec pigtail connector that matches your vehicle's factory plug, or a universal splice-in kit. Fit matters most here — a mismatched terminal count or wrong locking tab style will prevent a secure connection and can cause the same fault to return. Confirm the number of pins (typically 2 or 3) and the connector body style before ordering.

OE-spec pigtail connector
Best for
Exact-fit replacement with no modification
What you get
Pre-terminated wires matched to factory terminal count, correct locking tab, and proper wire gauge for the clutch coil circuit
Universal A/C clutch connector kit
Best for
Shops or DIYers who need a quick splice repair
What you get
Generic connector body with bare wire leads that are cut and soldered or crimped to existing harness — lower cost but requires more skill
Weather-pack sealed connector
Best for
Vehicles in high-humidity or off-road environments
What you get
Sealed terminal cavities and rubber wire seals that resist moisture intrusion and corrosion at the connection point
Connector with integrated inline fuse
Best for
Harnesses where the original wiring shows heat damage upstream
What you get
Adds a fusible element to protect the new connector and compressor clutch coil if an overcurrent condition caused the original failure

A/c compressor connectors brands we stock for your Peterbilt 357

Standard Ignition
2 options · from $7.95

Replacing the A/C compressor connector on a Peterbilt 357

Easy⏱ 30–60 minutesMultimeterWire stripper and crimping tool or soldering ironHeat-shrink tubing and heat gunTerminal pick or connector release toolElectrical contact cleaner

Disconnect the battery before beginning, then unplug the damaged connector from the compressor clutch and cut back the harness to clean wire. Splice the new pigtail connector using solder and heat-shrink or quality crimp terminals, match wire colors carefully, and route the new connector away from sharp edges or hot surfaces. Reconnect the battery, request A/C, and confirm the clutch engages before closing up the engine bay.

Frequently asked questions

How much does it cost to replace A/C compressor connectors on a Peterbilt 357?
Parts start at $7.95 for the Peterbilt 357. The connector itself is inexpensive, but labor varies depending on harness accessibility. A shop may charge one to two hours of labor on top of the part cost. DIY replacement is straightforward for most owners and eliminates the labor charge entirely.
Can a bad A/C compressor connector cause the compressor to stop working completely?
Yes. The A/C compressor connector carries the electrical signal that energizes the clutch coil. If the connector is open-circuited due to corrosion, a broken terminal, or heat damage, the clutch will never engage and the compressor will not pump refrigerant, regardless of system pressure or refrigerant level.
How do I test whether the A/C compressor connector is the problem on my Peterbilt 357?
Use a multimeter to check for battery voltage at the connector with the A/C requested and the system calling for cooling. If voltage is present at the harness side but absent at the compressor side, the connector itself is faulty. Resistance above roughly 0.5 ohms across a terminal also indicates a failing connection.
What causes A/C compressor connectors to fail?
Heat cycling near the engine is the primary cause — repeated expansion and contraction loosens terminal crimps and cracks the plastic housing. Road moisture and engine bay condensation accelerate terminal corrosion. In some cases, a shorted clutch coil draws excess current that burns the connector before the underlying electrical fault is diagnosed.
Will replacing just the connector fix my A/C, or do I need a new compressor too?
If the compressor itself is mechanically sound and the refrigerant charge is correct, replacing the connector alone will restore A/C operation. Always test clutch coil resistance after installing the new connector — a coil that reads open or shorted indicates compressor clutch damage that also needs to be addressed.
Is soldering or crimping better when installing a new A/C compressor connector on a Peterbilt 357?
A properly executed solder joint with heat-shrink tubing is the most durable repair in a high-heat environment. Quality ratcheting crimps using correctly sized terminal pliers are also reliable and faster. Avoid uninsulated butt connectors or electrical tape alone — both degrade quickly from engine heat and moisture in this location.

Shop a/c compressor connectors by year for the Peterbilt 357

1994199319921991199019891988

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A/c compressor connectors for other Peterbilt models

Peterbilt 377Peterbilt 378Peterbilt 379Peterbilt 375