It happens quite often; we see many street machines with the most aesthetically appealing gauges, only to find out the speedometer is far from functioning. Some will rationalize that it’s unnecessary in their weekend cruisers, while others have every intention of making it functional—one day.
The good news is that day is now. Auto Meter recently released a GPS speedometer interface that can transform any electronic speedometer into a GPS-based speedometer with minimal hassle. This unit is compact, making it easy to hide underneath the dash and only requires minimal wiring to complete the installation; three to be exact, along with the magnetic GPS antenna. And for the price conscious, these can be had for under $200.
For our installation, we enlisted a ’65 Chevelle that had already been outfitted with a complete set of Auto Meter gauges. In this case, the transmission was recently swapped out for an automatic overdrive, giving us the perfect opportunity to put the GPS interface to the test. Just how difficult was it? Hardly difficult at all, but follow along and check it out for yourself.
[01] The wiring harness comes...
[01] The wiring harness comes as one unit with an ample amount length of wire for various applications. The end also features a push on and lock connector that plugs into the GPS interface module.
[02] We first connected the...
[02] We first connected the red wire to a switched positive 12V on the American Autowire fuse panel.
[03] Next, we found a suitable...
[03] Next, we found a suitable ground and connected the black wire underneath the dash; another option is connecting it to the engine ground.
[04] The violet wire needs...
[04] The violet wire needs to be connected to the speedometer signal input.
[05] We chose to place the...
[05] We chose to place the magnetic GPS antenna on top of the dash; the most important thing is to mount the antenna where it has a clear view of the sky to receive the satellite signal. We should note that these are weatherproof and can be mounted outside; it can even be painted without affecting its performance.
[06] To keep the wiring clean...
[06] To keep the wiring clean and free from view, we pushed the wire between the glass, routing the wire toward the driver side and underneath the dash.
[07] With the wiring complete,...
[07] With the wiring complete, we simply connected the wiring harness and the antenna to the SMA connector.
[08] At this point all we...
[08] At this point all we needed to do was mount the GPS interface module; you have the option of using the two mounting points or do what we did and use double-sided tape to hold it in place.
[09] If you are using an electronic...
[09] If you are using an electronic Auto Meter speedometer, no calibration is necessary. The interface module is calibrated to 16,000 ppm (pulse per mile) and all Auto Meter electric speedometers are calibrated the same. For other speedometers, simply hold the calibration button until the needle gets close to but not over 80 mph; once released the needle will drop back down. Within 5 seconds, repeatedly tap the button until the needle reads 80 mph—that’s it. If you exceed 80 mph, then you will have to repeat the process.
[10] To verify the results,...
[10] To verify the results, we took a short drive around our facility while having one of our coworkers pacing us. Final verdict, this unit worked as described and its now on our CHP approved list.