page 8A-33-0 in the helm inc service manual

trying to wire up a dakota digital vss converter through the 8d ecm, i know for a fact the dakota box is recieving signall from the vss because its led is flashing which is the sign that it is.

there is a pink and black wire into the ecm that is power for the circuit, and it has a dotted line between it and the grey wire that goes out of the ecm to the speedo. This dotted line represents a mechanical connection, and that grey wire to the ecm is a ground on off switch based on ppm so im assuming this is how the signal is relayed to the gauge.

The first time i wired the dakota box i spliced into that pink and black wire before the ecm, and used it as power for the Dakota box. The speedo worked but the ecm threw a code and couldnt even be scanned so it was NOT happy.

i disconnected everything, got the ecm working again and wired everything for the dakota back up the same only used power off the gauges at the fuse panel.

Now it doesnt work. My only two guesses is that either that pink and black wire going into the ecm is necessary to power the dakota box and have it output a signal.

or im still spliced into one of the ecm wires that goes to a main chassis ground as my ground for the DD box. Is it possible that i could have a bad ground but the led on the box still be showing power and showing vss signal when the car is moving. I used a splice connector not just wrapped the wires together.

 

what color is the wire you are using for the output for the speedo? I believe mine was green.

Did you remove it from the ECM, or just tap off of it?

 

different ecm, theres no vss buffer
wire is grey as per the helm inc diagram, the two vss signal wires and the speedo output wire are all beside each other in one of the connectors.

the first time i had it when it worked i had it completly removed from the ecm, tried having it connected and spliced into afterwards but that was when it still didnt work.

nothing should need to go through the ecm, i disconnected the signal wires from the ecm from the vss too as those should go directly to the dakota box

the box is definitly getting the vss signal cause the led flashes when the car is moving. I just need to understand if the dakota box just needs any 12v power and will output a pulse per minute signal, in this case i probably just have a bad ground? but is it even possible for the ground to be so bad that its not outputting a signal but the led still be on, and flash when its recieving a signal from the vss?

or if something to do with that pink and black power wire that shows as part of the vss circuit is integral to the speedo working somehow?!

 

the speedo needs power as well as the input, AFAIK.
I dont think the green light would flash if the ground was bad, but i suppose it could be in series with the the speedo and thats why the light is on.

If you take off the kick panel on the passengerside, there should be a screw in the body, or even just use the screw hole from the screw that holds the kick panel on, ground a wire to that hole, and to the box just to make sure you have a ground. Or is you have a multi-meter, check for continuity form the ground on the Dakota box to the chassis.

If thats not it, i dont know why its not working.

 

i checked the speedo circuit in the wiring diagrams and it recieves power from the same place that my fuel and oil gauges do and both of those gauges are functioning

other then that it should just be the signal coming into it

i wonder if theres any way to test the wire coming out of the output to see if there is any signal coming out of the box??

 

probably, but you would need an analog multi-meter. I think the needle would bounce with the pulses, im not sure