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Brilliant Red Hybrid
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Discussion Starter #1
I'm in the process of getting all my swap info together, I'm planning on reusing my stock 98rs transmission, but swapping the whole 02wrx motor, wiring, ecu, dash into my rs. Will i have a problem using my rs speedo cable for the wrx cluster? any problems i should be worrying about? Or is this irrelevant to anything. What else should i watch out for in doing the swap, besides to change the rs clutch to a aftermarket stronger one?


Thanks
Jason
 

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Wiring Guru
01 RS, 97 Ducati
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355 Posts
The 98 RS uses a two wire VSS not a cable.

Being that you are planning on doing a dash swap that will not pose an issue. Doing a dash swap will pose an issue being that it is considerably more work and ends up looking like it was never intended to go in the car due to large gaps on the sides of the dash and other ill fitting parts. You'll still need to rewire the doors, lights and other components.

Z
 

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772 Posts
BUMP!

I need to convert my cable speedo to electric, I am NOT using a WRX (GD) wiring harness. How do I add the VSS? Where is the sensor on non-cable cars? I will use a GD cluster pigtail and hardwire everything (which is fairly easy for me) I just need a jumping off point to get started. The VSS is my only snag right now.

I am going to be using a 98 RS ECU also....

Worst case, I wonder how difficult itd be to add the cable driven speedo bits to a GD cluster. Maybe thats easier?
 

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Wiring Guru
01 RS, 97 Ducati
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355 Posts
You'll need to run power and ground to the sensor as well as your output signal which will go to the ECU and cluster. You'll also have to rewire the cluster harness to make a GD cluster work. You are also going to have to do a lot of cutting to make the GD cluster fit in the GC dash and the end results will be meh at best as part of the cluster will be covered.
 

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like i said, in the past it was a mechanical cable that ran the spedometer. the ecu has no idea how fast the car is going from that cable, it was purely mechanical to run the gauge speedo and odometer. it may have then run a wire from the cluster back to the ECU so the ECU could know how fast it was going, but i dont know about that (i think it does though?).

a usdm WRX has an electronic speed sensor that runs through the wiring harness and eventually ends up at the cluster. so on your WRX harness, assuming it is complete, there would be just another plug to plug in. dont think of it any differently than the rest of the sensors on the car, its just another plug you need.
 

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Im using a 98 RS ECU (car is a 96 Brighton 1.8) and the ECU plugs in and runs as is, I just need to add the knock sensor to the harness (and add the pin, which I have). The 98 ECU doesn't have an input does it? I thought it was cable driven. I'll pull some wiring diagrams tomorrow and see whats what. I was just thinking I could hardwire the VSS to the cluster just running wires. I guess I'll just have to try it.

I'm going to do a DIY so others in the future will have a step by step.
 

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97 L, 13 WRX
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like i said, in the past it was a mechanical cable that ran the spedometer. the ecu has no idea how fast the car is going from that cable, it was purely mechanical to run the gauge speedo and odometer. it may have then run a wire from the cluster back to the ECU so the ECU could know how fast it was going, but i dont know about that (i think it does though?).
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It does.
 

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Yeah, but what changed for 02-03? Surely a cable doesnt go into that...98ish they went to a VSS on the tranny. I will not have a cable speedo cluster anymore, so the cable goes no where. I need to figure out if it goes VSS -> ECU -> Cluster or VSS -> Cluster. On a 98 RS, why would the VSS go to the ECU? I could see if it was an auto tranny, but for manual, I'd think the VSS would go to the cluster. Am I right?
 

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1995 WRX 2015 F150
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For what you are trying to do, install a vss in the trans where the cable used to go. It screws in the same. Then wire it up to split the signal to both the 02 cluster and the 98 ecu.
 

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97 L, 13 WRX
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Cars with cable trans have a wire that goes from the cluster to the ecu so that it knows how fast the car is going. I'm not sure what it uses it for, but with an obd2 code reader you can see the vehicle speed.

On cars with a Electronic VSS in the transmission there is a wire that goes to both the gauge cluster (speedometer) and the ECU (diagnostics?).

So if you are using a cluster from a car with a electronic VSS then take out the cable and insert a electronic VSS and run wires to the cluster and ECU on the correct pins and it should work just fine.

Again, I'm not sure why the ecu needs vehicle speed, but it must use it for something.
 

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Hmmm, ok, thats cool.

I would think its for AT cars...the MT cars probably does nothing the ECU needs. I will do it just to make the car happy though.

So, I think I read I need an 02-03 VSS to match my cluster...the 98 RS one is different. Difference in voltage, etc.
 

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Bugeye and STiL
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i just looked at the wiring diagrams for a 98 rs that i used when i did my swap.
the speed sensor has two wires that go from the vss to the cluster and the cluster sends a conditioned signal over a single wire to the ecu.

the speed sensor is is a basically a inductive type trigger(kinda like abs or cam position sensors)which send pulses to the cluster which interpets the signal and sends it to the ecu so it knows how fast the car is going.
there is no power or ground to the sensor, only to the cluster.

pin a1+a3 on the cluster are the signal wires to the vss
pin b8 is power to the cluster from fb23 fuse #2
pin b2 is from the cluster to an engine ground
pin a2 is the wire that goes to the ecu on pin 83

:blowingup
 

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97 L, 13 WRX
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Hmmm, ok, thats cool.

I would think its for AT cars...the MT cars probably does nothing the ECU needs. I will do it just to make the car happy though.

So, I think I read I need an 02-03 VSS to match my cluster...the 98 RS one is different. Difference in voltage, etc.
Well, I am getting two different part numbers for the 98 RS and 02 WRX so that sounds right. But there may be a problem with that. If they produce two different signals then either the ECU or gauge cluster will not get the correct signal and possibly give you a useless speedo or a check engine light. I would just install the gauge cluster that corresponds with the ECU.

But I may be wrong, they could produce the same signal and you'll be fine. Hopefully someone else could chime in and shed some light on this.
 

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When doing any sort of swap, you want to match the VSS to the cluster in the car. Then hook the ecu to the vss signal, that signal may be from the cluster (cable style and 98 2 wire) or straight from the vss which would be all 3 wire style.
 

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BUMP!

I need to convert my cable speedo to electric, I am NOT using a WRX (GD) wiring harness. How do I add the VSS? Where is the sensor on non-cable cars? I will use a GD cluster pigtail and hardwire everything (which is fairly easy for me) I just need a jumping off point to get started. The VSS is my only snag right now.

I am going to be using a 98 RS ECU also....

Worst case, I wonder how difficult itd be to add the cable driven speedo bits to a GD cluster. Maybe thats easier?
 
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