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For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 1999 🢒 Isuzu MD Steel Tilt (F Model) 🢒 Body and Accessories 🢒 Instrument Panel, Gauges, and Console 🢒 Fuel Gauge Always Indicates Full

Fuel Gauge Always Indicates Full Single Tank

Step

Action

Value(s)

Yes

No

1
  1. Disconnect fuel sender or fuel sender and fuel pump harness connector at the fuel tank.
  2. Connect a fused jumper from CKT 30 (PPL) at the fuel tank connector to chassis ground.
  3. Place the ignition switch in RUN.

Does the fuel gauge indicate FULL?

Go to Step 2

Go to Step 5

2

Check for open in CKT 30, CKT 386, or CKT 24 (PPL) between the fuel sender and the IP harness connector.

Was an open wire found?

Go to Step 3

Go to Step 4

3

Repair the open in CKT 30, CKT 386, or CKT 24 (PPL) between the fuel sender and the IP harness connector.

Is the repair complete?

System OK

--

4

Replace the fuel gauge. Refer to Instrument Cluster Replacement .

Is the repair complete?

System OK

--

5

Connect a fused jumper between the CKT 30 (PPL) and the CKT 350 (BLK) at the fuel sender or fuel sender and fuel pump connector.

Does the fuel gauge indicate FULL?

Go to Step 6

Go to Step 7

6

Locate and repair the open in CKT 350 (BLK) between the fuel sender or fuel sender and fuel pump harness connector and ground.

Is the repair complete?

System OK

--

7

Replace the fuel gauge sender.

Is the repair complete?

System OK

--

Fuel Gauge Always Indicates Full Dual Tanks

Step

Action

Value(s)

Yes

No

1
  1. Disconnect harness connector at fuel sender and balance pump control module
  2. Connect a fused jumper from CKT 30 (PPL) wire at harness connector to chassis ground.
  3. Place ignition switch in RUN.

Does fuel gauge indicate FULL?

--

Go to Step 2.

Go to Step 4.

2

Locate and repair open in CKT 30 (PPL) wire from the fuel sender and balance pump control module harness connector to instrument cluster harness connector.

Is repair complete?

--

System OK

Go to Step 3.

3

Replace the I/P cluster. Refer to Instrument Cluster Replacement .

Is the repair complete?

--

System OK

--

4

Connect a fused jumper from CKT 30 (PPL) wire to CKT 350 (BLK) wire at fuel sender and balance pump control module harness connector.

Does fuel gauge indicate FULL?

--

Go to Step 5.

Go to Step 6.

5

Locate and repair open in CKT 350 (BLK) wire from the fuel sender and balance pump control module harness connector to splice S415.

Is repair complete?

--

System OK

--

6
  1. Connect a jumper from CKT 1936 (DK BLU) wire to CKT 30 (PPL) wire at fuel sender and balance pump control module harness connector.
  2. Disconnect connector at left hand fuel tank.
  3. Connect a fused jumper from CKT 1936 (DK BLU) wire at left hand fuel tank harness connector to chassis ground.

Does fuel gauge indicate FULL?

--

Go to Step 7.

Go to Step 8.

7

Locate and repair open in CKT 1936 (DK BLU) wire between the fuel sender and balance pump control module harness connector and the left hand fuel tank harness connector.

Is repair complete?

--

System OK

--

8
  1. Connect a fused jumper from CKT1936 (DK BLU) to CKT 350 (BLK) wire at the left hand fuel tank connector.
  2. Connect a jumper from CKT 1936 (DK BLU) to CKT 30 (PPL) wire at fuel sender and balance pump control module harness connector.

Does fuel gauge indicate FULL?

--

Go to Step 9.

Go to Step 10.

9

Locate and repair open in CKT 350 (BLK) wire between the fuel sender and balance pump control module harness connector and splice S415.

Is repair complete?

--

System OK

--

10
  1. Connect a jumper from CKT 1937 (LT BLU) to CKT 30 (PPL) wire at fuel sender and balance pump control module harness connector.
  2. Disconnect connector at right hand fuel tank.
  3. Connect a fused jumper from CKT 1937 (LT BLU) wire at harness connector to chassis ground.

Does fuel gauge indicate FULL?

--

Go to Step 11.

Go to Step 12.

11

Locate and repair open in CKT 1937 (LT BLU) wire between the fuel sender and balance pump control module harness connector and right hand fuel tank harness connector.

Is repair complete?

--

System OK

--

12
  1. Connect a fused jumper from CKT 1937 (LT BLU) to CKT 350 (BLK) wire at the right hand fuel tank connector.
  2. Connect a jumper from to CKT 1937 (LT BLU) wire to CKT 30 (PPL) wire at fuel sender and balance pump control module harness connector.

Does fuel gauge indicate FULL?

--

Go to Step 13.

Go to Step 14.

13

Locate and repair open in CKT 350 (BLK) wire from the fuel sender and balance pump control module harness connector to G408.

Is repair complete?

--

System OK

--

14
  1. Visually determine approximate fuel level in right hand and left hand fuel tanks.
  2. Use ohmmeter to check resistance between CKT 350 (BLK) and CKT 1937 (LT BLU) or CKT 1936 (DK BLU) wires on the fuel senders on each fuel tank.
    • An empty tank would indicate low resistance (approximately one ohm).
    • A full tank would indicate high resistance (approximately 88 ohms).
    • A partially full tank would indicate somewhere between those values.

Is sender resistance good?

--

Go to Step 15.

Go to Step 16.

15

Replace fuel sender and balance pump control module.

Is the repair complete?

--

System OK

--

16

Replace the applicable sender unit. Is the repair complete?

--

System OK

--