COMET CENTRAL

Has anyone used the VSS signal to power an aftermarket speedo? I have the 2 wire sender but I cannot find out how it should be wired. I did find a diagram that shows both wires (3 and 6)go to an ECM and one says +. I'm assuming the ECM is sending voltage to the sender but I'm wondering how much. I don't want to fry my speedo.

Lip Ripper wrote:Has anyone used the VSS signal to power an aftermarket speedo? I have the 2 wire sender but I cannot find out how it should be wired. I did find a diagram that shows both wires (3 and 6)go to an ECM and one says +. I'm assuming the ECM is sending voltage to the sender but I'm wondering how much. I don't want to fry my speedo.

2 wire VSS doesn't need voltage, just the 3 wire. With the two wire one wire goes to speedometer the other wire to ground.

Lou

Nothing goes to the ECM. The VSS generates it's own voltage. As I understand it,either wire is used for ground,the other to speedo.

Okay, then which is the signal wire? I have it wired with one to ground now and get nothing when I program the speedo.
I get an open reading to ground on both.

Lip Ripper wrote:Okay, then which is the signal wire? I have it wired with one to ground now and get nothing when I program the speedo.
I get an open reading to ground on both.

It produces a magnetic pulse, reason I think polarity is not a issue. And as vicegrip said either wire could be ground.Plus may be why you are getting a open reading???

But to test the VSS take a multimeter and hook the black lead to the one you think should be ground and the red lead to the other wire. And put the rear of car up on jack stands, and spin the rear wheels. The volts should go up on meter as the wheels spin faster. If it doesn't work try reversing the lead/wires. I think on the 2 wire sensors you use AC current on multimeter and on the 3 wire ones you use DC setting.

Once you figure out which wire you want for ground and which one for the signal lead I would run the ground to the same ground the speedo has.

Lou

Had the same situation with an Auto Meter speedo,2 wire VSS. Instructions were unclear so I called their tech support. Nobody there could give me anything so I flipped a coin and it worked.I would say you're getting no signal from your VSS or you have a bad ground or the wires on the back of the speedo could be hooked up incorrectly. Maybe run the ground to the same source as the speedo head...if you're sure that has a good ground.

Thanks guys, I will test the sender because I know my new wiring is correct.

Okay, the factory vss needs the cable plugged into it to create the signal. I don't have a cable. Autometer has 2 options, a magnetic sensor that picks up drive shaft rotation (not). or a GPS unit for the speedo I have. I don't like that idea either. Does anyone have the cable end lying around from a factory speedo? I'm thinking, cut the cable off and cap it, then plug it into the speedo so the factory vss can create a signal. Idea's?

Lip Ripper wrote:Okay, the factory vss needs the cable plugged into it to create the signal. I don't have a cable. Autometer has 2 options, a magnetic sensor that picks up drive shaft rotation (not). or a GPS unit for the speedo I have. I don't like that idea either. Does anyone have the cable end lying around from a factory speedo? I'm thinking, cut the cable off and cap it, then plug it into the speedo so the factory vss can create a signal. Idea's?

I might have my old speedo cable from my 3 sp trans,would that work?

I'm guessing here but I doubt it. Edit.. I have looked at used cables on ebay and I think I' may be mistaken. I need to test the one on the tranny.

Do a search for a ford vss pigtail for the transmission you are using. Lot of people sell them. Plug it into your sender and one wire goes to your speedo and the other goes to ground. Here is a picture of the ford sender with the plug with polarity



Hope this helps
tom

Stacey....does your T-5 have a mechanical speedo output or electronic? The device Tom recommended looks like an "adapter" that would connect to a mechanical speedo trans and convert the output to a VSS signal. I'm very interested in how this works out because I'm planning to update my instruments with an electronic speedo, and install a T-5. I'm hoping a T-5 with VSS output will work with the new speedo. I'm also planning to do the EPS conversion for power steering, probably using a unit out of a Toyota Prius, which defaults to 40% assist without VSS input. However, if the signal from a VSS equipped T-5 can be made to work an electronic speedo, I'm hoping it could also be used to provide the VSS input needed by the EPS to make it fully variable with speed. Please keep the info coming.
Jim

Stacey I have a VSS (I guess that is what it is called) on my '98 T5 it has a gear on it and a pigtail, is that what you need? I am not going to use it, going with a regular old cable so right now it is just plugging the hole, if you need it you are welcome to it just send me a PM or if you need me to take a picture I can.

I think it looks like what Tom posted.

See Ya,
Mike

I have the one like pictured above and I have the pigtail. Mike I think they changed after 93, that is what I have. Mine is a 2 wire. I'm thinking yours is a 3 wire. Autometer is who told me about needing the cable installed, I don't really see how that matters. And yes, mine is mechanical cable with the 2 wire vss on it. More to follow.

Mine has a VSS I grabbed out of a 2000 E 150 with the elec speedo.It had provision for a cable but just had a plastic plug installed instead. Worked fine with no cable.