Speed sender troubleshooting
Although there are 7 sender input types, there are only 2 different signals used by speedometers, Hall effect and AC sinewave.
Click the link for each type and how to troubleshoot.
HALL EFFECT SCREW-ON SENDER (3-WIRE)
This type can be for any make or model, it is a sender that replaces the traditional mechanical cable. It can be a screw on GM or bolt on Ford style
2-WIRE SCREW-ON SPEED SENDER
This is the sme as above designed to replace the mechanical cable, It has 2 wires and generates an AC sivewave signal.. It can be a screw on GM or bolt on Ford style
2-WIRE MAGNETIC PICKUP (OE OR INTEGRATED STYLE)
Has the same function as the screw-on style but is integrated into the transmission by the manufacturer. Generates and AC sinewave signal
TREMEC 2-WIRE SENDER
The tremec sender is the same as any OE style but the signal is generally a weak low-voltage AC sinewave at low speeds (under 30 MPH) You may have to change the speedometer sensitvity on air core gauges.
An alternate option is all Tremec transmissions have a Ford style speedometer cable output. This sender will work on Tremec Transmission cable outputs (you will need a drive gear and circlip)
To test the sender use the 2-WIRE MAGNETIC PICKUP (OE OR INTEGRATED STYLE)
PCM
Generally NVU gauges have been integrated with GM PCMs (computers) but other manufacturers may be similar. The GM PCM reads the speed signal from the VSS (Vehicle Speed Sender) and then outputs a hall effect signal. Check your PCM documentation or wiring harness manufacturer for the proper connection point. The signal is tested just like a hall effect sender HERE
GPS
Generates a signal from reading position based on GPS. Call the sender manufacturer directly. What is important is the pulse count coiming out of the GPS unit and the pulse count in the speedometer is the same. Pulse setting will vary on the gauge architecture check your manual.
OBD2
Boxes that are connected to a Vehciles OBD2 port and then generate a signal to be read by a speedometer operate similar to a GPS unit. The only issue is the OBD2 port is not designed for continous use and the signal may be dropped from time to time requiring the unit to be restsrted or the vehcile restarted.Pulse setting will vary on the gauge architecture check your manual.