Finding "Check Engine" Light Circuit
 

Didn't pass my emissions check because my "check engine" light was not operating. I want to trace the circuit to try to find the problem but can't find the light in my Chiltons manual. I do find a light called "malfunction indicator lamp". Is that the same as the "check engine light"? It's in the section of the electrical schematic named Instrument Panel Warning System. According to the schematic, it is a pink/light green wire going into the PCM. I have read that the "check engine light" is a ground functioning circuit to where the PCM completes the ground circuit when it finds a problem. Is this correct? The truck is a 1997 F150.

Yea, same thing, - CEL or MIL.

Just change the fuse or the bulb.

Thank you, jbrew. That's what I thought. I will check the fuses but I'm pretty sure for me, it's going to be a little more complicated than that. I replaced my hydrolocked 4.2 with a late model V8 and am using a stand-alone engine harness. The manufacturer of the harness has indicated the "check engine light" wire but now I have to tie it into the stock CEL....and I have to get power to the CEL because at the moment my whole instrument panel is dead. I'm using mechanical and electrical guages for oil pressure, water temp and voltage. Guess I'll build my own guage panel eventually.