Turbo Regal Engine Grounds
John Spina
Introduction
There are four ring terminals at the elbow of the wire harness, two of which attach to the rear of the passenger side cylinder head and two which attach to one of the bellhousing bolts. These engine ground points are succeptable to contamination by road salt, grease, etc., and occasionally become loose for some reason. These four ring terminals provide grounds for all of the engine sensors that require direct battery grounds. They also provide a ground feed for the ECM, A/C clutch, and digital dash (if so equipped).

If the ground connection becomes faulty, several problems may arise. It is essential to maintain ground integrity at the grounding points to assure proper operation of the electronics on the engine.
Ground Terminals and Feeds
The following will describe each ring terminal and its associated feed.

1. Ring terminal with two black/white 16 gage wires, short length:

  • A/C head pressure switch (gray connector)
  • Mass AirFlow sensor ground
  • EGR solenoid (EVRV) ground
  • Fuel pump relay ground
  • Coolant fan delay relay ground
  • ECM large connector (C & D) ground

NOTE: The internal splice connecting all these wires together is located about 4 inches from the ground ring terminals, inside the oval conduit.

2. Ring terminal with two black/white 16 gage wires, long length:

  • ECM large connector auxillary ground
  • C437 connector ground (feeds digital dash)
  • ESC module ground

NOTE: The internal splice connecting all these wires together is located about 12 inches from the large round grommet going into the passenger side, below the heater box.

3. Ring terminal with single black 12 gage wire, short length:

  • AC high pressure limit switch (round sealed connector at compressor)
  • Coolant fan ground

NOTE: The internal splice connecting these wires together is located about 18 inches from the Coolant Fan connector.

4. Ring terminal withone black/white wire and one tan wire, 16 gage, long length:

  • ECM small connector (A & B) ground
  • ECM large connector (C & D) oxygen sensor reference ground

NOTE: There are no internal splices on these connections; they are direct.

The ring terminal with a single 12 gage black wire, near the Powermaster unit is a ground connection for the Powermaster unit only.


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