GPS speedo wiring?

[FFRWRX]

This is a real long shot, but I'm running out of options.

I bought a car (not a F5) that has a GPS speedometer in it that doesn't work. The person I bought the car from doesn't seem to know anything about it. It had a universal GPS antenna that wasn't indicating a GPS signal, so I bought another one (different brand) and that one is working; light on it indicating it has a good GPS signal. The speedo works, but indicates way under the correct speed. The issue is, I know nothing about the speedo.

I've done an extensive search and can't find any info on these gauges. There is no manufacturer info on it, other than the "Daytona".

187834

The GPS antenna/sender has 3 wires that output different pulse rates. I've got the highest one connected to the lead in the speedo that had the previous connection; it reads far too low. I had it connected to a different pulse lead on the antenna and it barely read at all. There are a number of wires on the back of the speedo, so maybe it is a matter of connecting to a different one, or doing some calibration procedure. But without any info on the speedo, I wouldn't know what other wires to try.

187835

My only option at this stage is to replace the speedo with a different unit, and try to get a close match. Speedhut, who I have bought gauges from before, might be able to do a custom face to match it, but it would be a waste to toss a potentially good speedo.

Any help?

Rick

[Papa]

I found a diagram for an Autometer GPS antenna, and the antenna plug wiring includes a wire for power (red), ground (black), and signal (white). The antenna doesn't do any signal processing, so I'm not sure what you mean by three different pulse rates. The signals used for civilian ground equipment are all at 1575.42MHz. The signals transmit a constant code at 1.023Mbps. The code is unique for each satellite and the receiver requires at least four satellites to calculate location. Speed is calculated by the receiver based on distance between locations over time.

[FFRWRX]

I wasn't clear enough. The antenna unit that came with the car (that didn't work) had a white signal wire to go to the speedo. The replacement one I just bought, has 3 signal wires, labeled as:

Blue: 16,000 pulses per mile
White: 8,000 PPM
Orange: 4,000 PPM

From what I've read, most GPS speedos use the white, 8000 PPM signal. But the new GPS antenna unit obviously gives a choice depending on what the speedo requires. The one I replaced only had the one white lead. It also seems that most of the new GPS speedometers come with the antenna that only has one coaxial-type connector.

[Papa]

The ones that have a module between the antenna and gauge are something I'm not familiar with. The ones that just have the small SMA connector are for gauges that do all the processing within the gauge. It looks like what you have is a digital gauge with the GPS processing done in a module that outputs a pulse that the gauge uses to display the speed. I did see one that had calibration buttons inside the module. I looked, but couldn't find anything on the Daytona Instruments or the number on the back that looks like a part number.

[FFRWRX]

A little more info that may (or likely not) help.

This is another label on it:

188030

And this was under a label. I found the company, and they do make instruments, but I suspect the "Daytona" company just use their housing. As I write this it just occurred to me to ask them if they know Daytona Instruments.

188031

[FFRWRX]

Hey Papa, got it working. I emailed Faria, whose name is molded into the casing. The next day they sent me the instructions for a gauge (not Daytona) that has wiring exactly like mine. What was missing from mine was the wire for a switch to change modes (trip odometer, running time, etc, and a calibration mode). When in the calibration mode you indicate the start and end of a measured mile, or in my case a measured kilometre. I used Google Maps to find a street-to-street in my area that was exactly 1 km. It calibrated and then started working perfectly.

So while you didn't directly help me, it was the back-and-forth that gave me the idea of where to go for help.

Rick

[Papa]

Hey Papa, got it working. I emailed Faria, whose name is molded into the casing. The next day they sent me the instructions for a gauge (not Daytona) that has wiring exactly like mine. What was missing from mine was the wire for a switch to change modes (trip odometer, running time, etc, and a calibration mode). When in the calibration mode you indicate the start and end of a measured mile, or in my case a measured kilometre. I used Google Maps to find a street-to-street in my area that was exactly 1 km. It calibrated and then started working perfectly.

So while you didn't directly help me, it was the back-and-forth that gave me the idea of where to go for help.

Rick

I'm glad you got it working. Those are some really nice looking gauges and it would be a shame to have to replace them.

Dave