VSS Bench Test

[DPDISXR4Ti]

I seem to recall a discussion on this topic once, but don't recall if there was a final determination if the VSS could be tested for proper operation by any means other than installing it in the car. Anyone know?

[milehighXR]

Put yer volt meter on the leads in AC volts mode. Then put the peg into the VSS and spin it. It should start make voltage at that point. Alternately you could also just check the resistance. I can't remember the figures just, now. I have successfully rehabbed an XR VSS, and could repair yours if needed.

[Freejack]

That method won't work for the Scorpio though, since its a Hall effect sensor, rather than the variable reluctance sensor almost every other Ford has used.

For the Hall sensor, you will need a supply voltage, which I can't remember is 5 or 12V, then check the output wire. When spun, it will create a square wave signal. You should be able to use a analog voltmeter to read the signal.

Jake

[DPDISXR4Ti]

For the Hall sensor, you will need a supply voltage, which I can't remember is 5 or 12V, then check the output wire. When spun, it will create a square wave signal. You should be able to use a analog voltmeter to read the signal.

So I guess the 3 circuits have to be supply, gnd, and output, right? I'm assuming it doesn't ground through the mounting bolt or anything.

If you get a chance figure this out it would be good to document Jake. I've got one clipped with a harness clip, so I could take pics for clarity.

I was actually rather surprised to find the VSS still attached to the A4LD I pulled it from at the U-Pull. The car had been up on blocks since mid January, and nobody had taken the 5 minutes to get under there and remove the one bolt. I know it was there since mid January, cause I was the one who had them put it there.

[milehighXR]

For frame of reference Brad, the American A4LD VSS is a 2 wire unit. I imagine it would function like the XRs...

[Freejack]

Brad,

I will do. I will check the shop manual when I get home. I have a semi-functioning sensor at home too (works until it gets warm).

Jake

[Ed Lijewski]

The Scorpio VSS is a totally different unit from the XR VSS.

Ken Kizer (ScorpioNut) has researched, including dissecting one, Scorpio VSSs. Check his website (Aphenos....). Send him a PM re this post.

YMMV

[dimswits]

I was actually rather surprised to find the VSS still attached to the A4LD I pulled it from at the U-Pull. The car had been up on blocks since mid January, and nobody had taken the 5 minutes to get under there and remove the one bolt. I know it was there since mid January, cause I was the one who had them put it there.

You know full well that you and I are the only two people to have touched that car (and I touched it with a heavy hand), and I haven't been there since you had it put up on the blocks.

[DPDISXR4Ti]

The Scorpio VSS is a totally different unit from the XR VSS.

Did someone suggest otherwise?

[DPDISXR4Ti]

I was actually rather surprised to find the VSS still attached to the A4LD I pulled it from at the U-Pull. The car had been up on blocks since mid January, and nobody had taken the 5 minutes to get under there and remove the one bolt. I know it was there since mid January, cause I was the one who had them put it there.

You know full well that you and I are the only two people to have touched that car (and I touched it with a heavy hand), and I haven't been there since you had it put up on the blocks.

I saw your heavy hand and raised it with a hot torch. It sorta looks like it got hit with an IED at this point.

[Ed Lijewski]

The Scorpio VSS is a totally different unit from the XR VSS.

Did someone suggest otherwise?

Johnny's post did.

YMMV

[scorpioaddict]

I seem to recall a discussion on this topic once, but don't recall if there was a final determination if the VSS could be tested for proper operation by any means other than installing it in the car. Anyone know?

Yep. To bench test, connect the VSS to a speedo and supply voltage. This of course assumes your speedo is working, but they're pretty reliable. I can dig my setup out and give you the wiring layout if you need it. It might be in the EVTM but I haven't looked.

[DPDISXR4Ti]

Yep. To bench test, connect the VSS to a speedo and supply voltage. This of course assumes your speedo is working, but they're pretty reliable. I can dig my setup out and give you the wiring layout if you need it. It might be in the EVTM but I haven't looked.

Oddly enough, I have a Scorpio cluster. It's odd, as I've never owned a Scorpio and don't have any plans to own one. I really have no idea how I even came to own this, I just do. No harness clip, or it might be easy to make an educated guess which circuit is the VSS input.

[milehighXR]

The Scorpio VSS is a totally different unit from the XR VSS.

Did someone suggest otherwise?

Johnny's post did.

YMMV

Yeah, I saw it was Brads post, and didn't even look at what sub-forum it was in

[scorpioaddict]

Yep. To bench test, connect the VSS to a speedo and supply voltage. This of course assumes your speedo is working, but they're pretty reliable. I can dig my setup out and give you the wiring layout if you need it. It might be in the EVTM but I haven't looked.

Oddly enough, I have a Scorpio cluster. It's odd, as I've never owned a Scorpio and don't have any plans to own one. I really have no idea how I even came to own this, I just do. No harness clip, or it might be easy to make an educated guess which circuit is the VSS input.

The speedo has its own separate connector, a 5 pin thang. Looking at the back, the top/center connector is ground, the bottom left is 12 volts, and the bottom right is VSS signal. The VSS wiring is blk/blu is 12 volts, yel/brn is signal to the speedo, and brown is ground.

Run supply voltage and grounds to both the speedo and the VSS.

I just chuck the VSS up in a drill once it's all hooked up. That's enough revs to tell you if things are working.

Easier if you've made up a wiring kit for all those odd size round connectors...