# speedo from cable to electric



## dreambmx (Apr 29, 2014)

Hi everyone! New guy here with an 89 D21. The auto trans quit working so i swapped in a manual trans from a 95. My problem is that I dont have a speedo now. Has anyone put the the electronic speedo in the 89 cluster? If so, how did you wire it up? If i understood how the electronic speedo functioned I guess I might be able to figure the rest myself. I/E., power in to wire "A" and ground to "B" or whatever.

Thanks!


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## jp2code (Jun 2, 2011)

I have heard of people swapping the square dash for the round dash - and that would get you the electronic speedometer.

The electronic speedometer has a sensor that plugs into the transmission. The older speedometers used a cable. Can't you just use the mechanical parts from the older transmission, or do they not fit in the hole?


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## dreambmx (Apr 29, 2014)

The hole for the electronic speedo is quite a bit larger than the one for the mechanical speedo. I've seen the round top dashes in the earlier trucks too. My biggest hurdle is just figuring out the wiring from the transmission to the dash. If i can figure that out, I'm pretty sure that I can fab the rest. Thank you for your reply.


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## rogoman (Dec 16, 2004)

According to the FSM there's a speed sensor that's built into the combination meter instrument panel behind the speedometer head. The speedometer cable end screws into this sensor so it looks like there's no way to rewire anything. It looks like your best bet would be to fab up some sort of adapter at the tranny so that you could use the existing cable; if you have access to a good machine shop, it shouldn't be too difficult to make something.


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## dreambmx (Apr 29, 2014)

Right. I want to take a newer speedo head and swap it into the older square cable driven head spot. My biggest question is this. How would I need to connect the wiring from the sensor at the trans to the cable-less head? Does one side go to ground and then the other picks up a 12 volt feed? Thanks for your replies so far!


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## jp2code (Jun 2, 2011)

Not to knock this forum, but there are more people to ask on Infamous Nissan.


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## smj999smj (Jan 1, 2006)

The electronic speedometer pinion generates AC voltage via two wires to the head unit, which is then converted by the speedo head. So, there really is not a power and ground circuit, as it is alternating current.


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## rjesthull (Sep 7, 2019)

smj999smj said:


> The electronic speedometer pinion generates AC voltage via two wires to the head unit, which is then converted by the speedo head. So, there really is not a power and ground circuit, as it is alternating current.


wouldn't the ac signal be converted to dc by speedo processor and then sent to computer, thus needing a good ground?


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## smj999smj (Jan 1, 2006)

rjesthull said:


> wouldn't the ac signal be converted to dc by speedo processor and then sent to computer, thus needing a good ground?


Yes, that's what the speedo head doeson the 96: it converts the AC voltage from the VSS to DC voltage...and then signals the ECM. I was referring only to the 2-wire circuit between the VSS and the speedo head. Power and ground are supplied to the speedo head on different circuits via the printed circuit on the back of the cluster. Usually there are multiple ground points that will splice into a single wire that goes to an allotted terminal in the harness connector which contacts the printed circuit when the connector is plugged in. If my memory is correct, there are four small bolts that attach the 96 speedo head to the back of the cluster, which also create the circuit between the speedo head and the printed circuit. Two of the bolts (I believe they are 180 degrees apart) are used for the circuit between the VSS and the speedo head and the other two create the circuits, individually, of course, for the 12v power and the ground circuit. 

There is a lot out there as far as converting the square-style dash to the later, rounded-style dash and subsequently running the wires to the cluster from the VSS on the trans, but they are doing it with the later style cluster and doing the re-wiring of it. I don't recall anyone ever trying to install the later style speedo head into an early style cluster and I'm not sure if it'll work? I guess where there's a will, there's a way! Jp2code probably has the right idea in checking-in at Infamous Nissan's site as they might have somebody who has been in your situation, before. Perhaps there is a different cable that will work or, as mentioned, the aluminum end of the speedo cable might be able to be made to fit? Let us know how you make out!


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