My check engine light is always on even when there is no key in the ignition. What would cause this?

 

Year, model?

 

1988 f150 2wd 4.9l

 

Welcome to the site!
Eh, never ran across this before - if everything is shut down as it's supposed to be, the light shouldn't be on. Only thing I can offer is that there's a problem with the ignition switch down near the base of the steering column about above the brake pedal, where it's not really Off when the key is removed. Suggest either it could be out of adjustment with respect to the ignition key clocking, or as happened with mine - failed and broken apart.

As to why the light is even On is another problem beyond why it stays on with the key off.

Good luck, and keep us posted.

 

ok so here is the long story of everything that is going on with my friends 1988 f150 4.9l 2wd. he attempted to pass another vehicle and lost control and went into a bean field at which time it would not start. he brought it to me to fix. this is what it is doing.
1. battery drains in about 8hrs
2. check engine light stays on even after key removed
3. no fuel pressure from either 3 fuel pumps & no power to them. checked relay, its good. all fuses are good.
4. inertia switch is good