GT-1 Gauge Tester

The GT-1 Gauge Tester from Desert Classic Parts allows you to check the function and accuracy of the Temperature, Fuel and Oil Pressure gauges on all 60s and 70s FoMoCo vehicles. It will also test the functionality of the IVR (Instrument Voltage Regulator) that powers those three gauges.

It comes with easy to understand instructions, but here it is in a nutshell:

• Locate the sending unit.
• Remove the wire from the sending unit.
• Connect the GT-1's RED alligator clip to the wire you removed from the sending unit.
• Connect the GT-1's BLACK alligator clip to a good ground.
• Turn the ignition switch to ON or ACCY. I prefer ACCY - do not leave the ignition ON for long periods.
• Move the selector switch to the top (POWER TEST). This will test your IVR.
• If the LED blinks, your IVR is good.
• If you have an aftermarket solid state IVR the LED will stay on, not blink.
• If you have an OEM IVR and the LED stays on the IVR is faulty.
• If the LED does NOT blink, your IVR is bad or not grounded properly.
• Now select the next notch down (H 1F) to test that the gauge goes to FULL.
• Select the next notch down (M 2M) to test that the gauge goes to the middle of the dial.
• Select the next notch down (E 3E) to test that the gauge reads 1/2 a pointer width below EMPTY.
• Turn the ignition OFF.
• Disconnect the GT-1 tester.
• Reconnect the wire from the gauge to the sending unit.