Vss

[Royal-T-Ltd]

where's the easiest place to tap into the VSS, or to get speed information from the ECM harness???

tia

aaron

 

[The_Six]

brown wire off the VSS green module it is the wire that goes to the ECM.

 

[Royal-T-Ltd]

brown wire off the VSS green module it is the wire that goes to the ECM.

lol... thanx.... i found my wiring schematics last weekend and took care of it but thanx for the post... i am sure somebody will find this thread in the future

 

[pfredric]

Is the VSS signaling to the ECM a 5 volt square wave or 12 volts square wave?

It is my understanding that this VSS is 2000 pulses per mile.

TIA.

 

[RmvBfrFlght]

It is most likely a +12 volt signal. I didn't check a '7148 ECM, however, other ECMs of this era use a 5.1K ohm resistor to +12 volts as a pull-up.

The buffer box doesn't really output a voltage, it only pulls the signal to ground. Which is why the ECM has the PU resistor. IIRC, there are two outputs on the buffer, the other being used for the cruise control module in some vehicles.

RemoveBeforeFlight

 

[pfredric]

It is most likely a +12 volt signal. I didn't check a '7148 ECM, however, other ECMs of this era use a 5.1K ohm resistor to +12 volts as a pull-up.

The buffer box doesn't really output a voltage, it only pulls the signal to ground. Which is why the ECM has the PU resistor. IIRC, there are two outputs on the buffer, the other being used for the cruise control module in some vehicles.

RemoveBeforeFlight

Thanks for the reply. What you say makes sense as I look at my service manual.