In some extremely rare cases the gauges & instruments found in certain vehicles require a special input signals that must be specifically tailored.

For you "Tech Types" this signal is a "Zero Crossing Sine Wave" commonly generated by VR (Variable Reluctance) sensors. This sensor is used in many applications because it is extremely cheap to manufacture. It is akin to winding a wire around a nail and pointing it at the spinning gear to be measured. This is not a very advanced sensor therefore it is prone to outputting a very "loosely controlled" signal.

Most gauges & Instruments will work perfectly with our "Universal Square Wave Output Driver". This output driver is square wave based and only approaches zero volts. In other words the two signals are completely different and incompatible.

This page will list vehicles that are known to (or at least have a high probability) of requiring the "Square Wave To Sine Wave Converter" unit.

We have kept the price of this unit basically "at cost" and we will refund your money upon the return of the "Square Wave To Sine Wave Converter" should you not need it.

If you choose to purchase one of our SpeedChanger or TachChanger products (obviously only the ones with electrical outputs would have this issue) and don't purchase this converter and subsequently carefully follow the installation directions and still can not get the system to work try this simple test.

Connect a regular 9Volt battery positive terminal (+) to the vehicle ground and the 9Volt battery negative terminal (-) to the SpeedChanger or TachChanger negative (black) wire. If this results in a fully or partially functional installation you need one of the "Square Wave To Sine Wave Converters".

If you find that your vehicle needs a converter and your vehicle is not listed here, Please drop us an email and let us know what type of vehicle you have. This will save the next guy the guess work. Thanks so much.

Listed here are the vehicles we have found that some models MAY require this converter.

Mustangs, Ford Pickups & Most Ford Vehicles
Mid '90s Corvette, 1992.5 Camero

Thanks for your patience and check back often.

The TERF Inc. Technical Development Team.

3588 Plymouth Road #232
Ann Arbor, Michigan 48105
(248) 210-8009 Phone
(800) 975-1445 Phone
(509) 752-8083 Fax

Price: $20.00*
*Plus Shipping and Handling

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