Hi Guys, I've removed my entire instument cluster, and I'm working on wiring in a set of digital gauges. My orginal speedo was an cable driven, but I'm wondering what is that yellow box behind the board? It has what looks like some kind of optical counter that gets a signal from the speedo???

Is it a VSS that sends a signal to the ECM? I dont really have a way to put it back in with my new speedo, since it's electronic, and I'm sure the pulses wont match the new sender.

I drove it around the block without it, and it didn't seem to bother anything.

Thanks!
ck

 

Yes, that is the VSS & buffer. The optical head picks up the reflections froma bar that rotates with the speedo. This was lost when you went with the electronic speedometer.

The ECM needs a 2004 PPM signal in order to calculate the MPH. This is used for IAC, shift light and TCC control.

You will need to either put an inline unit on the end of the speedo cable, or install a mag sensor in the trans (not sure if this is possible without changing to a newer tranny).

RBob.

 

If you have the stock motor and trans in your car... It will make a difference. It allows yout lockup on an automatic transmission to turn on/off, and if you have cruise control... it controls that as well.

I installed a Nordskog Digital Panel in my camaro and retained the stock sender by disassebling the speedometers internals to clear the circuit board