Testing A No Park-Lamps Problem (1997-1998 Ford F150)

TEST 4: Testing The Continuity Of The Park-Lamps Circuit

So far, your test results have confirmed that:

• Fuse #7 is not blown (TEST 1).
• The TAN/WHT wire of the grey headlight switch connector has 10 to 12 Volts DC present (TEST 2).
• The park-lamps come ON when you jumpered female terminals 4 and 5 of the grey headlight switch connector (TEST 3).

Our last test will be to check the continuity of the park-lamp circuit inside the headlight switch.

We'll accomplish this test by doing a simple multimeter resistance test in Ohms mode.

Alright, let's get started:

1. 1

   Place your multimeter in Ohms mode.

2. 2

   With the headlight switch's knob in it's ‘headlight's off’ position.
   
   Your multimeter should now show NO continuity. This is usually represented on the multimeter's screen by the letters OL.

3. 3

   Turn the headlight switch knob to the ‘park-lamps on’ position.

4. 4

   Test for continuity between male spade terminals 4 and 5. See the photo above.
   
   If all is OK, your multimeter should register continuity (5 ohms or less).

5. 5

   Turn the headlight switch knob to the ‘head-lamps on’ position.

6. 6

   Test for continuity between male spade terminals 4 and 5. See the photo above.
   
   If all is OK, your multimeter should register continuity (5 ohms or less).

Let's take a look at what your test results mean:

CASE 1: The multimeter DID NOT register continuity. This tells you that the headlight switch is defective and needs to be replaced.

CASE 2: The multimeter registered continuity. This test result tells you that the park-lamps circuit, inside the headlight switch, is OK.

More 4.6L, 5.4L Ford Diagnostic Tutorials

There are quite a few tutorials for the 4.6L and 5.4L equipped Ford F150, F250 pick-ups and Expedition SUV. You can check them out in this index:

• Ford 4.6L, 5.4L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Clean The Ford MAF Sensor (Ford 4.2L, 4.6L, 5.4L).
• How To Test The Fuel Injectors (1997-2002 4.6L F150).
• How To Test The Ford EGR Valve EGR Vacuum Solenoid, DPFE Sensor.
• How To Test The Ford MAF Sensor (4.2L, 4.6L, 5.4L).
• How To Test The 4.6L, 5.4L Ford Throttle Position Sensor (TPS).