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ZBUM's Nissan Z31 300ZX Warning Lights

This page is to describe the warning lights (also called idiot lights) found in the instrument cluster of the Z31. It is to show their meaning and give the more common solution to the problems. It is important to know if the lights are in working condition. The simple check is to turn the key to the "ON" position but do NOT start the car. At this time, all warning lights should come turn on. After a few seconds, some of the lights may turn off. This is considered normal.

image name problem solution
Sensor Comes on every 30,000 miles. Check and replace (if needed) the oxygen sensor. Then reset the sensor light. Drop the glovebox door by pressing in the sides releasing the door stops from their holes. Remove the screws (4 trim/2 latch). Pull the box out and lower it out of the way. At the top of the glovebox frame slightly to the left locate a relay. On the right side of the relay you'll feel a rubber-covered button/plunger. Press it in and you'll hear the relay spring reset. Turn the ignition switch on, the sensor light should be off. Reassemble.

After 90,000 miles you disconnect the light. Remove the panel just below the steering wheel (at the drivers' knees). On the left you will see a group of wires taped together going into a wiring harness. Taped to this group of wires will be another wire (green/yellow I think) with a plug (white plug) - this is the wire for the sensor light - unplug it.

This description (or something close to it) can be found in the Haynes manual - look under Oxygen Sensor in the index.

Fuel Fuel Level is low Put gas in the gas tank. This light usually comes on with about 3 to 5 gallons of gas left in the 19 gallon tank.
Seatbelt Seatbelt isn't fastened. Put your seat belt on. This flashes for a few seconds when you first turn the car on.
Door Door is open One of the doors is open. It could be either driver or passenger door or the trunk.
Brake Parking brake is on or brake fluid is low. Usually, when this light is on, the fluid level in the master cylinder is low. This usually happens around the time you need new brake pads. The master cylinder is designed so that when you have brand new pads, and the level is full, that you can run your pads to minimum thickness and just touch the low mark. Of course, this light also could mean your parking brake is on. If you have full fluid, check the fluid level switch. Simply unplug the connector that is located on the side of the master fluid resevoir. If the light goes out, the switch is stuck. Clean or replace the switch. If the light stays on, the pin switch in the parking brake may have lost its contact point. Replace the stopper for the pin switch.
Alternator There is a problem with the charging system. This light typicaly means the alternator has taken a dump. Usually, a few of the other lights come on at the same time. Simply replace the alternator. Be sure you have the auto parts store test the old alternator first. And before you leave the store, have them test the new alternator as a number of rebuilt alternators end up being dead on arrival. The voltage regulator is internal to the alternator, so you replace the whole thing as one unit.
Oil Pressure You are low on oil pressure. First, is the harness plugged in to the oil pressure sending unit? Second, do you have oil? Third, are there any valve noises? Finally, when was the last time you replaced the oil pressure sending unit?
Radiator Coolant level in the overflow bottle is low. Fill the overflow bottle with coolant. If you have coolant in the bottle, the switch is stuck. Remove the whole overflow bottle and clean with some CLR (calcium, lime, rust) remover.
Headlight One of the head lights is out. Replace the headlight. If both head lights are functioning, then there is a problem with the head light sensor.
Taillight One of the tail lights is out. Replace the burned out bulb in the tail lights. If all four tail lights are functioning, then there is a problem with the tail light sensor.