Hi i have a fully loaded 95 riviera. It has the check engine light on and its odb1. somenoe told me that you can scan it myself by pressing a button combination on my DIGITAL TEMPERATURE CONTROLS, (the a/c and heat) how do i do this and how do i read the codes.

Off and warm if it works on this car. Similar to Cadillac with OBD1

IIRC, this feature does not work on any display newer than 1993!

If it is an OBD1 can't you just bridge the two terminals on the plug and get the code from the flashes on the SES light? I haven't done that for a while as all my cars are OBD2 so I forget exactly what pins you jumper, but they are right next to each other.

I even got a little tool years ago from AutoZone called a "code key" and it just bridges the two terminals there...

IIRC, this feature does not work on any display newer than 1993!

Yeah I thought that function was eliminated around then.

If it is an OBD1 can't you just bridge the two terminals on the plug and get the code from the flashes on the SES light? I haven't done that for a while as all my cars are OBD2 so I forget exactly what pins you jumper, but they are right next to each other.

I even got a little tool years ago from AutoZone called a "code key" and it just bridges the two terminals there...

95 was a transitional year called obd1.5 by the repair industry, you will need a scanner capable of accessing this pcm.