What other than the ecm will cause the ses light to lum? If I ohm the ses output on my ecm to ground after isolating the wire from my dash harness I am open which tells me the ecm is not bringing my ses on. Also if I unhook the harness from the ecm turn ign to on the ses is still on. WTF

 

What year model is it?
It sounds like there is either a short in the dash itself or the wiring harness to the ECM.
If it's a short in the harness, track it down instead of putting in a new wire.
If you have a harness short, and it only affects the SES light, count your blessings...

 

87 camaro with 89 gta 5.0 tpi sounds like a mess i know got everything sorted out except this ses situation. I can unhook the gauge assembly and am still getting continuity to ground on the ses circuit. which tells me it is in the wire purple/wht I think.
Please correct me if I'm wrong.

 

SES light circuit going to ECM should be a BRN/WHT going into the ECM at A5. It may look purple.
At the dash connector it should have tan/blk wire (B14) next to it on one side and brown wire (B12) next to it on the other. This is going by gauges dash on an '88 which should be the same.

 

This is what was causing the ses light to come on. It was in my dash behind the stereo and a/c selector switches. Any Idea what it is or does?

 

That is interesting as hell. Not a clue. The best guess I can come up with is that it is something that maybe if the A/C had a fault it could turn on the SES. It is not on an '88.

 

It's the SES light driver board. I thought it was there on all models..
Anyway, if you Ohm across the diode and get a short, then there is a short either in the diode or the transistor. If you can unsolder one of the legs on the diode then you know which one of them is gone. If it's the diode then you can leave it out, it's just for protection but it's not important.
If you find no short then there's an unfulfilled input criteria to the circuit to make the light go out.

 

I bypassed it and the ses light functions properly. I can check the codes by jumping the aldl plug and the ecm sends my code 12 as it should. I was hoping that it was not a circuit to allow another component to activate the ses light without backfeeding voltage to the ecm.