Ford F150 Pickup. Manual - part 1569

Fig. 336: Identifying Instrument Cluster Harness Connector C254 
Courtesy of FORD MOTOR CO. 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

Fig. 337: Identifying Instrument Cluster Harness Connector C258 
Courtesy of FORD MOTOR CO. 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

Fig. 338: Identifying Instrument Cluster Harness Connector C252 
Courtesy of FORD MOTOR CO. 

Testing 

1) Check SIL Operation 
 
Inspect SIL while driving vehicle. SIL should turn on when optimum shift RPM for each gear is reached. 
SIL should turn off after shift is complete or while in top gear. If SIL is always illuminated, go to step 4). 
If SIL does not illuminate, go to next step. 

2) Check METER Fuse (10-Amp) 
 
Remove METER fuse and inspect. If the fuse is okay, reinstall fuse and go to next step. If fuse is not 
okay, repair short circuit as necessary. Replace SIL circuit fuse. 

3) Check SIL Bulb 
 
Remove SIL bulb and inspect. Using a DVOM, perform a continuity check if you suspect an open 
filament and cannot determine the bulb's condition visually. If the SIL bulb is okay, go to step 5). If the 
SIL bulb is not okay, replace SIL bulb. 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline

  

4) Check SIL Circuit For Short To Ground In Harness 
 
Turn ignition switch to OFF position. Disconnect PCM. Using DVOM, measure resistance between the 
SIL circuit at PCM harness connector and the battery negative terminal. If resistance is greater than 10 
k/ohms, replace PCM. If resistance is not greater than 10 k/ohms, repair short circuit. 

5) Check IGN Start/Run Voltage To SIL Socket 
 
Turn ignition switch to OFF position. Remove SIL bulb. Turn ignition switch to ON position. Using a 
DVOM, measure voltage of the SIL circuit between the SIL socket and chassis ground. If the voltage 
greater than 10.5 volts, turn ignition switch to OFF position and go to step 8). If the voltage is 10.5 volts 
or less, repair open SIL circuit. 

8) Check SIL Circuit For Open In Harness 
 
Turn ignition switch to OFF position. Disconnect PCM. Using a DVOM, measure resistance between SIL 
circuit at PCM harness connector and SIL bulb socket. If resistance is less than 5 ohms, replace PCM. If 
resistance is 5 ohms or greater, repair open circuit.  

TEST KM: A/C CLUTCH RELAY & A/C CIRCUITS 

Diagnostic Aids 

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used 
to diagnose the following:  

z

Wiring Harness Circuits (ACCS, ACPSW, VPWR & WAC). See Fig. 339-Fig. 349  

z

Faulty A/C clutch Relay  

z

Faulty Powertrain Control Module (PCM) 

NOTE:

A break in step numbering sequence occurs at this point. Procedure skips 
from step 5) to step 8). No test procedures have been omitted.

NOTE:

A/C relay or A/C clutch relay may also be referred to as Wide Open Throttle A/C 
Cut-Off (WAC) relay.

NOTE:

After each service or repair procedure has been completed, reconnect all 
components. Clear DTCs. Start engine and allow to idle. Turn A/C on and wait 
15 seconds. Turn A/C off, then turn ignition switch to OFF position. Repeat 

QUICK TEST

 procedures to ensure all EEC-V systems are working properly and 

DTCs are no longer present.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Self-Diagnostics - CNG, Flex-Fuel & Gasoline