I searched the forums for about an hour and could not find anyone else with a 87-91 truck with the same problem so here goes:


1987 F150 5.0 EFI 4sp manual 4x4

up until two nights ago the truck ran fine.

wife got up yesterday morning to take the truck to work, put the key in the ignition and nothing happens. here is where it gets troublesome for me.

At some point in the truck's life the ignition switch actuator broke, a common problem with these trucks. for some reason, the previous owner or the one before that, didn't fix it properly, but instead wired in a plunger button to the starter solenoid, basically up until now, to start the truck:

Key goes into ignition, turned to KOER position
jiggle wheel/column till accessory power comes on (see a CEL, guages register, radio comes on, etc...)
insure truck is in neutral and/or clutch is depressed
push plunger button
truck cranks and fires over
drive off

to shut the truck off all i've had to do is turn the key to the off position and remove it from the cylinder.

so Today comes along, I figure, must be the ignition switch. I take the wheel off, disassemble the top of the column, and tilt the column down and away from the dash. I replace the ignition switch with a brand new one, replace the ignition switch actuator (stupid cheap pot metal...) and still nothing.

I checked the fusible links coming from the battery side of the starter solenoid, all of them looked fine as far as I could tell there is no applicable fuse for the ignition.

there are also some fusible links on the driver's side by the harness going into the body by the PCM on the firewall, these also look fine, but I think this is going to be a huge pain in the ***.

so far i've learned:

battery terminals are very messy/corroded, lots of greenish whitish build up on both terminals

Problem is, KOER there is nothing happening, no power is going to gauges, radio, dash lights, chime etc. if key is in ignition and I open door, chime and cab lights come on as they're supposed to, if I push the jerry rigged start button the engine cranks but doesn't fire. this wasn't happening as of 10pm yesterday. something happened between 10pm yesterday and 830 am this morning to cause this.

Starter in truck hardwired with what appeared to be house wiring
Blower motor in truck hard wired with 30A fuse
ignition could've probably been fixed with a 15 dollar part way back when instead of wiring in a switch)

Thinking back and remembering when i could get the truck to start before, it involved jiggling the column/wheel up. this could suggest there is a lose connection somewhere up under the dash right? I'm thinking the ignition wire coming from the harness connection in the firewall may be loose from accidentally getting kicked.

I dont believe it's any mechanical part of the ignition, I think its an open circuit issue.

there is a 12v constant coming into the ignition switch from the starter solenoid via fusible link, runs from the fusible link into the harness, and comes into the cab via the connector in the firewall, this brings in Key on power to all the cab functions i believe (radio, gauges, chime etc...) I also believe there is a relay involved somewhere and a ground.

here's what I got as of this AM

I borrowed a multimeter and put it on volts, and checked my battery from post to post 12.3 volts. it's low but not a game changer,
i then checked voltage from each side of the starter solenoid on the fender, 12.3v
I then checked the 10pin harness plug up by the firewall on the driver's side. 11.7v
I then dropped the column back down and pulled the switch, I checked each of the battery terminals and got 11.6-11.7 volts from the two blades identified as BATT (the big fat yellow wires) by grounding the meter to the steering column.

here's my bit.

I took about 8in of 12ga wire and tried jumping the plug that goes into the ignition switch, tried jumping either of the battery pins to the other pins and got nothing. the accessories didn't come on, the truck didn't chime like it was in the KOER position, no idiot lights, and it didn't attempt to crank off the switch plug.

what am I missing here? i checked continuity on the brand new switch and it seems to be working.

I have power coming to the switch, i put the switch back in and hook up the plug to the switch, while holding it in my hand I try to manually operate the switch with a screw driver but nothing. does the switch ground to the column?

this is driving me crazy!

 

12 hours later and not one suggestion?

dang.

bought a new ignition switch. hoping it was just a fluke and I got a bad one. we'll see I guess.