7747 Check engine light on but no codes

[NorCal69]

What you describe is just a light, not a CEL (Check Engine Light). The CEL gets 12V ignition power and a wire from the ECM that grounds the light to turn it on. I don't recall the pin number off hand, but it is a brown/white wire.

I am working with an Howell harness that I purchased used. The original purchaser was never able to get his vehicle to run properly and removed the kit without ever leaving the garage.
The harness provides two leads to the CEL. One is a power supply and the other is a ground. I wired the CEL exactly the same way that I have in previous installations. This has me thinking that there is something wrong with the ECM or mismatch of PROM calibration and CALPAK cylinder counts.

[tayto]

what # on the connector does the SES ground wire goto? should be A5...

[NorCal69]

Yesterday I was looking over a previous TBI install and something donned on me.
Initially when I wired this kit I had a single lead bulb housing and connected the ground to the speedometer housing. I realized that that CEL light housing needed to be isolated with a ground wire and plastic housing. A little digging through the jeep parts stash produced this housing. Sure enough, the CEL light functions as it should now.