Diagnostic Aids

WARNING: This page is about a different car, the 1995 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.

Perform this test when directed by CIRCUIT TEST VPWR. This CIRCUIT TEST is intended to diagnose:

Wiring harness circuits (DC, DLC and GND).

Fig 1: Identifying DLC Circuits & Connector Terminals

Fig 2: Identifying DC Circuits & Connector Terminals

DLC CIRCUIT INFORMATION

Circuit

PCM Pin No.

⁽¹⁾ BOB Pin No.

Wire Color

DLC

Yellow/Red

DLC

Yellow/Blue

DLC

Yellow/Black

GND

⁽²⁾ Black/Red

⁽¹⁾	Rotunda Breakout Box (007-00033).

⁽²⁾	Black at DLC connector.

1) Check Ground At DLC Turn ignition off. Locate Data Link Connector (DLC). Measure resistance between GND terminal at DLC and ground. If resistance is less than 5 ohms, go to next step. If resistance is at least 5 ohms, repair ground circuit.

2) Check For Continuity Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Check for continuity between breakout box and DLC connector as follows:

Test pin No. 32 of breakout box and DLC (Yellow/Black wire) terminal of DLC harness connector.
Test pin No. 45 of breakout box and DLC (Yellow/Red wire) terminal of DLC harness connector.
Test pin No. 51 of breakout box and DLC (Yellow/Blue wire) terminal of DLC harness connector.

If continuity is not present, go to next step. If continuity is present, go to CIRCUIT TEST PGC.

3) Check Power At DC Turn ignition off. Disconnect MIL Diagnostic Connector (DC), located in left side of engine compartment, below coolant overflow reservoir. Turn ignition on. Measure voltage between DC harness connector Gray/Blue wire and ground. If voltage is 10 volts or more, go to next step. If voltage is less than 10 volts, check 10-amp METER fuse of interior fuse box. If fuse is okay, repair Gray/Blue wire.

4) Check Continuity Turn ignition off. Leave PCM disconnected from breakout box. Check for continuity between breakout box test pin No. 48 and DC terminal of DC harness connector. If continuity is not present, repair circuit as necessary. If continuity is present, go to CIRCUIT TEST PGC.