Now you can quickly determine if the gauges in your car are accurate with this gauge tester. You can verify the high medium and low reading for your gauges, and also shows that the Instrument Voltage Regulator is working.
If you own a classic Ford, Lincoln or Mercury you know that the gauge readings are often not what you would expect. It's common to have the temp gauge reading hot when the car is actually not hot at all, fuel gauges that read perpetually low, or oil pressure gauges that seem to be inaccurate.
Simply unplug the sender and attach the tester with the supplied alligator clip leads, turn the ignition on, and verify the function of your gauges.
Gauge Tester for all Ford products from 1956 to 1983
Is that gauge reading right? Now you can find out.
Want to know why the Temp gauge reads too hot, or the Fuel gauge too low, or the Oil Pressure gauge shows nothing at all? Now there is an inexpensive way to find out.
Now you can test the accuracy of Fuel, Temperature, and Oil Pressure gauges, plus verify output from the Instrument Voltage Regulator.
The slide switch lets you test the gauges at high, medium, and low readings. The Power LED will flash if you are using a mechanical regulator, or glow continuously if you have a solid state regulator. Simple instructions are printed on the back. The case is steel and made to last.
It's very easy to use. No need to access the gauges or disassemble the dash. Just unplug the sender, and attach the red lead to the wire you just unplugged. Attach the black lead to ground. Set the switch. Turn on the key, and read the gauge.
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Gauge Tester Instructions
For your gauges to provide accurate readings two other things must also work properly. First the Instrument Voltage Regulator (IVR) must supply an average output of 5 volts. Second the sending units for Oil Pressure, Water Temperature and Fuel Level must output the correct values. The Gauge Tester checks for IVR operation, and then substitutes for the senders to supply the correct signal to verify gauge readings.
Connection For Testing
Disconnect the sender. Connect the red lead to the wire you just disconnected from the sender. Connect the black lead to ground, not the sender. Put the key in the ACCESSORY or RUN position. Note: do not leave the key in the RUN position for an extended period of time without the engine running. It may take the gauge up to two minutes to reach it's final position.
Trouble shooting tip: Most failed gauges read low or nothing at all. Be sure to check that the needle is not in contact with the face of the gauge or bent. It may be possible to adjust low reading gauges. This is a very delicate procedure that should be performed by a professional.
Power Test
Connect the Tester as specified above. Put the switch on the tester in the Power Test position.
The Fuel, Temperature, and Oil pressure gauges are all powered by the Instrument Voltage Regulator. The electromechanical version of this regulator puts out pulses of power that averaged over time are equivalent to 5 volts. Newer solid state regulators provide continuous 5 volt output. The first test of any gauge begins with verification of the power source.
A properly working electromechanical IVR will flash between one and three times per second. The actual frequency is not important, the flashing indicates a working IVR. Solid state IVRs will illuminate the power light continuously.
Trouble shooting tip: If all gauges read high or low this is an indication that the output of the IVR is too high or too low and it should be replaced. Solid state replacements are more stable and not affected by temperature changes. If all gauges are pegged on high first check the IVR ground. The IVR must be grounded to function. If the ground is good, the IVR is defective and must be replaced immediately as the gauges can be damaged.
Position 1 Hot Temp, High Oil Pressure, Full Tank
Connect the Tester as specified above. Put the switch on the tester in position 1 (H F). The high reading for all gauges is the factory calibration point. The design of the gauge makes this the most precise indication of gauge function, and the only actual calibration point used by the factory.
Gauge designs vary but the center line of the pointer should fall between the two edges of the marker line. On some gauges there are two marker lines, the pointer should end up between the two lines.
Position 2 Mid Point
Connect the Tester as specified above. Put the tester switch in position 2 (M). The Mid Point of the gauge is less precise than the High reading. The center line of the pointer should fall within 1/8th inch of the center line of the gauge.
Trouble shooting tip: If your gauge reads correctly in the high position but incorrectly in the middle and low position the gage is either defective or it requires professional adjustment.
Position 3 Low Oil Pressure, Cold Temp, Empty Tank
Connect the Tester as specified above. Put the tester switch in position 3 (L/C,E). The Low point of the gauge is the least precise reading. Begin the test by observing the location of the pointer with the key off. When you turn the key on, the gauge pointer should slowly rise to the Low or Empty marker. It may take two minutes for the reading to stabilize. The center line of the pointer should reach the edge of the lowest marker line on the gauge. Due to the design of the gauge the low reading my fall within a window of 1/8th inch above the lowest edge of the marker line.