I tried to use the diagnostic function on my 82 Firebird a while back to sort out an engine problem but when I shorted the two pins on the connector no light flashed. I took out the instrument cluster yesterday and found that there was a bulb missing. Now I am wondering why was this removed. The car has a 2.8L engine and some previous owner removed most of the emision control stuff, no catalitic converter or EGR. The air conditioning is also gone. If I put back in the bulb will it remain on all the time with the emisions stuff gone? or how does it work.

 

The lack of EGR can cause the SES light to illuminate and error codes to be stored. The lack of CAT and no AIR won't do it.

The SES will typically come on during steady cruise when the EGR has been disabled.

RBob.

 

Thanks Rbob,
I don't really know what to do now. If I put back in the bulb I will have this flashing when I am driving and If I don't I won't be able to read the error codes. This is a tough call.

 

An idea: run wires up to where the bulb normally is down to the ALDL connector, use a small LED & 1k ohm resistor, mount LED at the ALDL connector, can just glue it in place. Note that the LED is polaity sensitive, it will work wired in one direction but not the other.

Can now have the SES out of the way, can't see it while driving, and can still pull codes.

RBob.