Hey All, happy St. Patty's day,

During a recent issue (TFI mod failure) I attempted the EEC self test to get the trouble codes. I followed the directions for the self test from the Haynes manual, it told me to connect the test light to the POS side of the battery.

If memory serves (hindsight) it was supposed to be the NEG side, and web sight research have backed that thought up.

It sparked a bit when I connected to wire to the battery (from the EEC self test connector) I did not think much of it. I hopped in the cab and the check eng light was on, with no key in..... I put key in, waited for the codes, nothing. Check eng light just stayed on. Then I smelt "burnt electronics" got out of and unhooked the wire.

Now I have no Check eng light, Cruse control does not work, truck bogs down when I hit the accelerator. I fear I killed the Comp. It had full 12 volts running through it for 2 minutes or so.

Has anyone done the self test like the Haynes 87-95 F-series and Bronco before and had this issue? Or is the a way to test that the ECM still works without the EEC or check eng light. I am a bit over my head on this.

I understand the ECM is only 2 bolts and a wiring harness, But if I get one at a junk yard I will need to confirm it works and well, and I don't like bolt and pray mechanics. If some one has a "Pin Voltage Chart" for my truck it would be greatly appreciated.

1990 F-150 XLT 4X4 300 IL6 manual.

Thanks, God Bless,
Stan