Section 17-01: Lighting, Exterior | 1996 F-150, F-250, F-350, F-Super Duty Motorhome and Bronco Workshop Manual |
DIAGNOSIS AND TESTING
Pinpoint Tests — Stoplamps
NOTE: Use Rotunda 73 Digital Multimeter 105-R0051 or equivalent when performing electrical pinpoint tests.
PINPOINT TEST F: STOPLAMPS/HI-MOUNT STOPLAMPS INOPERATIVE
F1 CHECK SUPPLY TO STOPLAMPS
- With Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, check for voltage on Circuit 10 (LG/R) at stoplight switch.
Is battery voltage present?
F2 CHECK SUPPLY CIRCUIT TO STOPLIGHT SWITCH
- Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, check Circuit 383 (R/W)/10 (LG/R) at output side of I/P fuse panel fuse 13.
Is battery voltage present?
| Yes | No |
|---|
| REPLACE fuse or SERVICE Circuit 383 (R/W)/10 (LG/R) for open circuit. RESTORE vehicle. RETEST system. | GO to F3. |
F3 CHECK CIRCUIT 383 (R/W)/10 (LG/R) FOR SHORT
- Remove IP fuse panel fuse 13.
- Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, connect second lead to output side of IP fuse panel fuse 13.
- Measure resistance.
Is resistance 5 ohms or less?
| Yes | No |
|---|
| SERVICE Circuit 383 (R/W)/10 (LG/R) for short to ground. RESTORE vehicle. RETEST system. | REPLACE damaged fuse. RESTORE vehicle. RETEST system. |
F4 CHECK STOPLIGHT SWITCH OUTPUT
- Depress stoplight switch and hold.
- Using a voltmeter connected to a known good ground, check Circuit 511 (LG) at stoplight switch.
Is battery voltage present?
| Yes | No |
|---|
| GO to F5. | REPLACE damaged stoplight switch. RESTORE vehicle. RETEST system. |
F5 CHECK STOPLIGHT SWITCH INPUT TO MULTI-FUNCTION SWITCH
- Gain access to the multi-function switch. With Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, connect other end to Pin C1-9, Circuit 511 (LG) at the multi-function switch connector.
- Apply brake pedal, and hold.
Is battery voltage present?
| Yes | No |
|---|
| GO to F6. | SERVICE Circuit 511 (LG) for an open. RESTORE vehicle. RETEST system. |
F6 CHECK MULTI-FUNCTION SWITCH OUTPUT TO STOPLAMPS
- Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, and brake pedal still applied, check Circuit 9 (LG/O) at Pin C1-10 of multi-function switch connector, or Circuit 5 (O/LB) at Pin C1-2 of multi-function switch connector.
Is battery voltage present?
| Yes | No |
|---|
| LEAVE brake pedal applied. GO to F7. | REPLACE damaged multi-function switch. RESTORE vehicle. RETEST system. |
F7 CHECK STOPLAMP SUPPLY AT BULB
- Gain access to either stoplamp connector. Disconnect stoplamp connector.
- Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, check Circuit 9 (LG/O) and Circuit 5 (O/LB) for voltage.
Is battery voltage present?
| Yes | No |
|---|
| GO to F8. | SERVICE Circuit 9 (LG/O) or Circuit 5 (O/LB) for open circuit. RESTORE vehicle. RETEST system. |
F8 CHECK STOPLAMPS GROUND
- Unapply brake pedal.
- Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, connect second lead to Circuit 57 (BK) at either stoplamp bulb connector.
- Measure resistance.
Is resistance 5 ohms or less?
| Yes | No |
|---|
| REPLACE damaged miniature bulb. RESTORE vehicle. RETEST system. GO to F9. | SERVICE Circuit 57 (BK) for open circuit. RESTORE vehicle. RETEST system. |
F9 CHECK SUPPLY TO REAR HI-MOUNT LAMP
- Remove rear hi-mount lamp as outlined.
- Connect one lead of a voltmeter to a known good ground, connect other end to Circuit 511 (LG) at stoplight switch connector.
- Apply brake pedal.
Did test lamp illuminate?
| Yes | No |
|---|
| RELEASE brake pedal. GO to F10. | SERVICE Circuit 511 (LB) for open circuit. RESTORE vehicle. RETEST system. |
F10 CHECK REAR HIGH-MOUNT LAMP GROUND
- Connect Rotunda 73 Digital Multimeter 105-R0051 or equivalent to a known good ground. Connect second lead to Circuit 57 (BK) at hi-mount stoplamp connector.
- Measure resistance.
Is resistance 5 ohms or less?
| Yes | No |
|---|
| REPLACE damaged stoplamp miniature bulb. RESTORE vehicle. RETEST system. | SERVICE Circuit 57 (BK) for open circuit. RESTORE vehicle. RETEST system. |
PINPOINT TEST G: ONE OR MORE STOPLAMPS INOPERATIVE
G1 CHECK STOPLAMP SUPPLY AT BULB
- Gain access to either stoplamp connector. disconnect stoplamp connector.
- Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, check either Circuit 9 (LG/O) or Circuit 5 (O/LB) for voltage.
Is battery voltage present?
| Yes | No |
|---|
| GO to G2. | SERVICE Circuit 9 (LG/O) or Circuit 5 (O/LB) for open circuit. RESTORE vehicle. RETEST system. |
G2 CHECK STOPLAMPS GROUND
- Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, connect second lead to Circuit 57 (BK) at either stoplamp bulb connector.
- Measure resistance.
Is resistance 5 ohms or less?
| Yes | No |
|---|
| REPLACE damaged miniature bulb. RESTORE vehicle. RETEST system. | SERVICE Circuit 57 (BK) for open circuit. RESTORE vehicle. RETEST system. |
PINPOINT TEST H: STOPLAMPS/HI-MOUNT STOPLAMPS ON CONTINUOUSLY
H1 STOPLIGHT SWITCH CIRCUIT TEST
- With stoplight switch in the OFF position, use Rotunda 73 Digital Multimeter 105-R0051 or equivalent to measure voltage at the output side of the stoplight switch, with Circuit 511 (LG) disconnected at splice.
Is battery voltage present?
| Yes | No |
|---|
| REPLACE the stoplight switch. RESTORE vehicle. RETEST system. | REPAIR short to power at individual suspect lamp. RESTORE vehicle. RETEST system. |