Technical Fitting a GPS speedo, need to find a switched live please.

[Ian S]

Fiat Cinquecento Sporting 1998.

Perhaps this weekend, I'm planning to fit a GPS speedo which will need a +12V live that the key switches on and off, and an earth connection.

I'm guessing as earth will be easier to locate.

So I wondered if anyone here could suggest a suitable +12V wire.

Why am I bothering? The car speedo hasn't worked for years, possibly due to the plastic cog in the gearbox, and the MOT now requires a working speedo. The garage I go to wanted hundreds to try and look the gearbox and seemed unenthusiastic. And the OE speedo was not anywhere near accurate anyway.

Thanks.

 

[fingers99]

Just a moment. Check that you don't need an odometer as well, or you'll be quids out.

Just use a multimeter to find a switched earth. Ciggy lighter is a good place to start, but get the lighter itself, not the light. Use an inline fuse.

Speedo may well be the cable. Pretty sure the drive is removable with the gearbox in place!

 

[Ian S]

Thanks, good advice I already did discover that it does need a tamper proof (ie, non-resettable) odometer to pass the MOT. I bought the DS100 which has that plus a resettable trip meter.

Another thing to note is that such a device needs to poll the satellite very frequently, not once per second like many satnavs do, or it'll be no use for late braking approaching cameras, were that to ever need to happen. The DS100 polls at 10Hz. I looked at the Speed Hut ones from USA, nice but only 5Hz and in their video the stepper motor driven needle appeared to lag too much for my liking. And a lot more expensive once taxes and post are paid.

Yes I went under there while it was on the ramp for some other work and the gearbox does have the removable cover plate. But still, I guess at least one of the shafts have to come out, etc, not sure now, dif out? They didn't want to know, and I didn't want to pay a shed load. I can't do that kind of thing under the car in the street any more. From what I read up on these forums the other year, the favourite was the worn plastic cog. I was going to take the car there this week to see if they would at least put it up and take off the cable from the gearbox to ascertain the integrity of the cable. But yesterday while I was on the phone to them I bought the speedo. One really needs to have an accurate idea of the speed these days. And if I invest quite a bit more than I already have in this car then I'll never get any of that back from a resale, but I will recoup some if I sell the GPS speedo.

I was hoping there would be switched +12 V behind the instrument panel as I plan to fit the speedo in front of the existing one so the wires will probably have to tuck in there somehow. I'll have a look at the lighter though in case that's easy.

Thanks.

 

[fingers99]

None of the shafts have to come out of the box.

Good luck with it!

 

[blu73]

Ciggy lighter is a good place to start, but get the lighter itself, not the light.

Mine is permanently live, although its entirely possible the wiring has been messed with at some point - but i think cig lighter is normally permanently live in a cinq. There is definately a switched live behind the stereo, my mind is sayings its a yellow wire but as said, use a multimeter and you should find one easy.