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Replacing the speedometer with the LCD version.


edrach
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I currently have a '97 Impreza with 5MT and a cable driven speedometer. Since I occasionally run TSD rallies with the car, I'm considering swapping the speedometer out with the later LCD version and adding the transmission mounted VSS found on the later Imprezas. Primary reason being that the old VSS in the speedometer head is a reed switch/magnet arrangement which TSD rally computers don't like.

 

Has anyone done this in the past and what issues had to be overcome to make the system work properly?

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Yes, I retrofitted a electronic speedo from a 98 Forester cluster into a 92 Legacy cluster.

 

VSS threads right into the transmission no problem. Take the cable out, pull out the rubber washer/seal doohicky if it didn't stay with the cable, and put in the VSS. The twisted pair of wires go straight from the VSS to the electronic speedo head. The speedo head has a + and - connections for the VSS. Then you have to make a jumper to the VSS output from the speedo head to the computer, the trace is already there for the reed switch in the cable head. You need ground, key-on power, and constant power. All those are available on different parts of the cluster, so you just have to run jumper wires here and there and tuck them under screws.

 

Now with a 97 impreza, you may be able to direct swap a 98 or 99 or 00 or 01 cluster in, depending on what year they switched over. You would need to check the pinouts, and you would have to run the pair of wires to the VSS, but that would be the easiest way. I would look at wiring diagrams for both years and make sure the same wires are coming in on the same pins in the same connectors. You might be lucky and it's nearly plug and play.

 

With a first gen legacy, there is no newer cluster that fits the same hole in the dash, so I had to get creative with the air body saw, files, and hot glue to make it fit.

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thanks. It's not so much I want to get an electronic speedo but I want to get clean VSS pulses from the later version sending unit rather than the noisy reed switch VSS in the cable driven speedometer. I'm looking for a way to tie the later version VSS unit into my speedo cable. I need to be able to get pulses off the cable without having to modify the harness so drastically. Once I get the sending unit in there, I'll just have to wire power, ground and signal from there to my rally computer.

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The VSS can't co-exist with a cable. It's either or. So you need to do a electronic speedo to convert to using a VSS. The electronic speedo is also needed to send the vss signal to the ECU.

 

I didn't modify the harness at all on the legacy I converted. I did all the wiring using jumpers from power sources already on the back of the cluster. The most work was making the electronic speedo head physically fit in the cluster.

 

Check wiring diagrams to see if the electronic speedo cluster is reverse compatable with the cable speedo cluster. You might be lucky.

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When I figure out how to install the sender in the two piece cable, the car's electronics won't even know it's there since it will only be wired to the rally computer.

 

I was hoping swapping the speedo for the LCD version would work more easily, but I'm not into re-wiring the car. Too complicated for a simple guy like me. However, thanks very much for your information.

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Correct me if I am wrong, but didn't older subarus have a two piece cable where the center part was the speed sensor for the cruise control?
"older" meaning EA or...?

 

that's not how i remember it but maybe you're saying the same thing that i'm thinking? it's just a simple sheathed cable. the cable slides out of the sheath that holds it, that's it. the cable sticks out of the end of the sheath and slides into the speedo head.

 

is that what you mean?

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"older" meaning EA or...?

 

that's not how i remember it but maybe you're saying the same thing that i'm thinking? it's just a simple sheathed cable. the cable slides out of the sheath that holds it, that's it. the cable sticks out of the end of the sheath and slides into the speedo head.

 

is that what you mean?

 

I know some cars used that system, I could have sworn i had a sooby like that I can be wrong (I had an 81 and a 89). Myabe other older cars?

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Correct me if I am wrong, but didn't older subarus have a two piece cable where the center part was the speed sensor for the cruise control?
My '97 Impreza does have a split cable about 8" from the transmission end. I suspect it's just there to make it easier to swap out; i.e. if the break is at the lower portion, replacing just that portion is easy. If the break is the longer upper portion, just slipping the cable out of the sheath might make it easy to fix. Somewhere here on the USMB someone posted a link to the speedo cable and part numbers. Darned if I can remember where.

 

In any event, the junction of the cables on my Impreza is just that with nothing between them. My VSS is generated by reed switches in the speedo portion of the cluster. It would be nice if earlier models had a sensor there because it would likely fit and be usable for my rally computer.

 

Here's the URL, posted by you (thanks). Found that on the companion thread I started when this forum didn't get much response.

http://opposedforces.com/parts/impreza/us_g10/type_99/manipulation/speedometer_cable/

Edited by edrach
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