1969 442 parking brake light
thanks Michael
Oldsdruid
Joined: Dec 2007
Posts: 10,617
From: Southside Vajenya
Boy, you've picked a tough one to diagnose. Do the other warning lamps function normally in bulb test? All light, none out or dim?
It's powered thru the ignition switch via the "GAUGES-TRANS" fuse, so it should have power only when the ignition switch is in ON/RUN position. Either the brake differential switch underhood or the parking brake pedal switch will activate it by completing the circuit to ground. It should be OFF at all other times.
However, this circuit feeds all the warning lamps as well as the fuel gage and transmission kickdown switch, and there could be a possible backfeed from the alternator and/or voltage regulator thru the ALT indicator lamp.
Disconnect battery, then lift the red wire from the alternator post. Tape it so it doesn't short against anything and reconnect the battery. See if light goes out. If yes, your problem is in the alternator wiring.
If still lit (we're assuming a 442 with internal regulator alternator), disconnect battery, reconnect the alternator post wire and battery, and with engine stopped unplug the two-wire connector at the alternator. If it goes out, problem is in the alternator itself.
If still lit, you've got a wiring issue or possibly an internal short in the ignition switch, though if that were the case every warning lamp on the circuit should be lit.
Has the wiring harness ever been replaced? You can try unplugging the transmission kickdown connector and the fuel gage, but I can't see any backfeeds in the wiring diagram that would allow them to cause this problem.
You do own a 1969 Olds Chassis Manual, right? You'll need it.
It's powered thru the ignition switch via the "GAUGES-TRANS" fuse, so it should have power only when the ignition switch is in ON/RUN position. Either the brake differential switch underhood or the parking brake pedal switch will activate it by completing the circuit to ground. It should be OFF at all other times.
However, this circuit feeds all the warning lamps as well as the fuel gage and transmission kickdown switch, and there could be a possible backfeed from the alternator and/or voltage regulator thru the ALT indicator lamp.
Disconnect battery, then lift the red wire from the alternator post. Tape it so it doesn't short against anything and reconnect the battery. See if light goes out. If yes, your problem is in the alternator wiring.
If still lit (we're assuming a 442 with internal regulator alternator), disconnect battery, reconnect the alternator post wire and battery, and with engine stopped unplug the two-wire connector at the alternator. If it goes out, problem is in the alternator itself.
If still lit, you've got a wiring issue or possibly an internal short in the ignition switch, though if that were the case every warning lamp on the circuit should be lit.
Has the wiring harness ever been replaced? You can try unplugging the transmission kickdown connector and the fuel gage, but I can't see any backfeeds in the wiring diagram that would allow them to cause this problem.
You do own a 1969 Olds Chassis Manual, right? You'll need it.
Thread Starter
Registered User
Joined: Apr 2011
Posts: 124
Boy, you've picked a tough one to diagnose. Do the other warning lamps function normally in bulb test? All light, none out or dim?
It's powered thru the ignition switch via the "GAUGES-TRANS" fuse, so it should have power only when the ignition switch is in ON/RUN position. Either the brake differential switch underhood or the parking brake pedal switch will activate it by completing the circuit to ground. It should be OFF at all other times.
However, this circuit feeds all the warning lamps as well as the fuel gage and transmission kickdown switch, and there could be a possible backfeed from the alternator and/or voltage regulator thru the ALT indicator lamp.
Disconnect battery, then lift the red wire from the alternator post. Tape it so it doesn't short against anything and reconnect the battery. See if light goes out. If yes, your problem is in the alternator wiring.
If still lit (we're assuming a 442 with internal regulator alternator), disconnect battery, reconnect the alternator post wire and battery, and with engine stopped unplug the two-wire connector at the alternator. If it goes out, problem is in the alternator itself.
If still lit, you've got a wiring issue or possibly an internal short in the ignition switch, though if that were the case every warning lamp on the circuit should be lit.
Has the wiring harness ever been replaced? You can try unplugging the transmission kickdown connector and the fuel gage, but I can't see any backfeeds in the wiring diagram that would allow them to cause this problem.
You do own a 1969 Olds Chassis Manual, right? You'll need it.
It's powered thru the ignition switch via the "GAUGES-TRANS" fuse, so it should have power only when the ignition switch is in ON/RUN position. Either the brake differential switch underhood or the parking brake pedal switch will activate it by completing the circuit to ground. It should be OFF at all other times.
However, this circuit feeds all the warning lamps as well as the fuel gage and transmission kickdown switch, and there could be a possible backfeed from the alternator and/or voltage regulator thru the ALT indicator lamp.
Disconnect battery, then lift the red wire from the alternator post. Tape it so it doesn't short against anything and reconnect the battery. See if light goes out. If yes, your problem is in the alternator wiring.
If still lit (we're assuming a 442 with internal regulator alternator), disconnect battery, reconnect the alternator post wire and battery, and with engine stopped unplug the two-wire connector at the alternator. If it goes out, problem is in the alternator itself.
If still lit, you've got a wiring issue or possibly an internal short in the ignition switch, though if that were the case every warning lamp on the circuit should be lit.
Has the wiring harness ever been replaced? You can try unplugging the transmission kickdown connector and the fuel gage, but I can't see any backfeeds in the wiring diagram that would allow them to cause this problem.
You do own a 1969 Olds Chassis Manual, right? You'll need it.
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