Ok, I have a small problem. I recently changed out my heater core on my 98 F150. It was a moderately inconvenient task, as anyone who as removed all of the dash and electrical systems from the cab can tell you.... Anyway, after I got the new heater core in and put everything back together, the turn signal and interior lights began to flash on and off when the battery was connected. Putting the key in the door and unlocking it didn't fix the problem, and turning the ignition results in the engine turning over, but with obviously no spark. I have a keyless entry system, but never used it and lost the remotes when I moved. Anybody have any ideas? Thanks

 

Is this a factory system?

 

OK, after giving it a break for a while, I went back over everything. Turns out I forgot to plug the inirtia fuel switch back in, and if you do that, the interior lights flash and chime. Who'd have thought? Ooops.