Harlan points to IU, IU install doc is on a z28....is the pinout on the '01 C5 PCM's the same as the '01 Fbody? I would doubt it, but not sure...just need to find that engine RPM lead to tap into...I think I'm putting my Autometer Mini on the pillar to the left of the steering wheel....:cheers:
If you need to install a RPM shift light such as an Autometer 5340 in a C5, I installed the one I had on my ZR-1.
You need to splice into pin 10 off the red PCM connector, which is a white wire, and also make sure that the shift light is setup for a four cylinder ignition to operate properly.
Being the signal is low, setting to 8 cylinders will not trigger the light, thus the fix is to set it to 4.
The issue is that the "tach output" off the computer on the '98+ LS1 motor is the
same as that of a four cylinder ignition (2 pulses per crank rev).
Making this cylinder selection adjustment has made the light work, and no ill effects should be seen.
This now gives you a way to set when the shift light comes on as to what RPM module you plug into the shift light unit.
This is great for when doing drag racing and you want to shift every time at the same RPM.
Being the tach updating is a bit slow by PCM, by the time the light comes on you might already have hit the rev limiter ( I had this issue).
One way to help solve that when using the Autometer is if you have a model that uses a light bulb which takes longer to light up, is buy the optonal LED which is 4 LEDs grouped together, it replaces the normal light bulb and LEDs come on quicker.
To my understanding its still the same pin.
Yes this was on my '99 but others have used the same pin.
See if the wire color is the same on pin 10, checking your service manual will quickly show what pin it is on your model.