I have a 5.0 HO EEC4 injected 78 F150.

I'd like to have a working check engine light and I'd like to use the "fasten seatbelt" dummy light on the dash as my check engine light.

Does anybody know which wires I need to connect the dummy light to?

Thanks

 

Does your new harness have a connector like this?



Read that caption: the CEL goes from key-switched power (Wh/Pu or R/Y or Pu/Y or...) to Pk/LG.

 

Thanks Steve, yes I do have those under the steering column. I've been using them to read codes using a 12v test light.

So the power to my CEL just has to be a key on source and the other I could splice on to the CEL wire on the diagnostic port? Sounds easy enough. Now I gotta find the fasten seatbelt wires. ;-)

 

Why not just add a 12V light somewhere? If you get an illuminated switch & install it in the dash, you can wire it up so the switch triggers the diagnostic mode, and its illumination is the CEL all the time.