Command Trac Lamp Out; Upshift Lamp Out; Brake Lamp Out - Jeep 1987 Wrangler Workshop Manual

INDICATOR LAMPS
2. BULB SOCKET: Ignition ON
TEST
O K
NOT OK
Battery side of bulb socket 12 volts Replace printed circuit
Terminal 3, 6 or 7,
depending upon bulb
12 volts Replace printed circuit
TROUBLESHOOTING —Command Trac Lamp Out
1. VACUUM SOURCE: Engine running; Command Trac switch in 4WD
TEST
O K
N O T O K
Check for vacuum supply
to switch
Vacuum present Repair as necessary. Refer to M.R. 279
2. COMMAND TRAC SWITCH: Engine running; Command Trac switch in 4WD
TEST OK
NOT OK
Battery side of switch 12 volts Repair open from printed circuit
Switch housing to ground Zero ohms
Clean ground connection
If zero ohms, replace switch
TROUBLESHOOTING —Upshift Lamp Out
1. UPSHIFT LAMP SWITCH CIRCUIT: Ignition ON; transmission in 1st gear
TEST OK
N O T O K
Jumper wire from diag-
nostic connector terminal
D2-1 to a clean chassis
ground
Lamp ON
Lamp OFF; proceed to switch test
Lamp ON; proceed to ECU test
Indicator Lamps 39
2. UPSHIFT LAMP SWITCH: Ignition ON; transmission in 1st gear; jumper
removed
T E S T
OK NOT OK
Switch Terminal A 12 volts Repair open from printed circuit
Switch Terminal B 12 volts Replace switch
If 12 volts, repair open to ECU Terminal T8
TROUBLESHOOTING — B r a k e Lamp Out
1. PARK BRAKE SWITCH: Ignition ON; parking brake applied
T E S T
OK
NOT OK
Ground wire to park brake
switch
Lamp ON Lamp ON; replace switch
Lamp OFF; repair open from ignition switch
2. BRAKE PRESSURE WARNING SWITCH: Ignition ON
T E S T
OK
N O T O K
Switch Terminal B 12 volts Repair open from printed circuit
Switch Terminal C 12 volts Replace switch
Ignition switch
Terminal Gl
12 volts Repair open from switch
If 12 volts, replace ignition switch
Indicator Lamps 39