The truck will not start when turning the key, but will if I jump the two posts on the starter solenoid (on the firewall) with a screw driver. I've replaced the starter solenoid once when this issue first occurred, but I'm still unable to start the truck unless I jump the two posts.

A few weeks ago I removed the starter, had it tested at an AutoZone, and it passed without issue.

Using a multimeter, if I test the negative terminal on the battery and the small signal wire that pushes on to the solenoid, I'm reading ~7.53v regardless of whether the key is being turned or not. It should be either 0v or 12v, correct? Would this indicate the ignition switch (not to be confused with ignition cylinder?) and/or wiring as the issue?

Shifting the truck into neutral and trying to start (even while jiggling the shifter) does nothing.

I'm not hearing any clicking noise at the starter solenoid OR the starter, but I do hear clicking in the interior fuse panel (I also have power to the radio). Does this rule out the ignition switch? I did replace the airbag clock spring around the time this started occurring, so I'm wondering if I didn't screw something up putting everything back together.

Thanks for the help!

 

No.

The starter circuit in this truck is what I call "stupid simple".

Ignition switch > Fuse F21 > Clutch Jumper (Auto) > DTR switch > starter relay.

Check fuse F21 under the dash. If good, use your meter on the fuse test points and measure voltage when the key is in START. If no input voltage, go back to the ignition switch. If input and output voltage at the fuse is good, go check at the DTR switch. Continue with your testing direction based on continued half-splitting the circuit until the open is isolated.

Here's a diagram of the circuit "downstream" from the ignition switch. It's for an Expy, but it's identical to your F150.




If you get stuck, just ask. Do not wander off into the weeds.

 

Pardon my ignorance, but which side is which when looking at the fuse holder? I believe the left prong was giving me 0.5v and the right prong was giving me 0v. Based on this, I'm assuming it's the ignition switch - I was under the impression that shifting the truck to neutral and starting it would bypass the DTR switch.

Also, I was able to start the truck if I jump the solenoid's terminal that goes to the battery + and the signal wire. From what I'm told, this indicates a good solenoid, so the issue must be wiring/ignition switch/etc. related.

I've tried replacing the ignition switch, but I'm running into an issue. The replacement will bolt up perfectly with the pin going into the hole, but it seems like I'm unable to fully turn the key in the crank position to crank the truck. Because of this, I'm not hearing that clicking sound in the fuse box that I get when I use the original ignition switch. I've thrown the original back in, and the key turning works/fuse panel clicking returns. At first I figured this might be a defective ignition switch, but I've gone through two at Advance Auto and now one at Napa, and they all have the same issue. What am I missing here?

 

Don't remember offhand, test them both if necessary.

No. The function of the DTR switch is to PERMIT starter engagement ONLY when in P or N. There's no bypassing going on.

The problem does sound like it's with the ignition switch, but not the switch itself. I suspect a mechanical misalignment or fault in the mechanical linkage that connects the cylinder with the electrical switch. Back in there behind where the cylinder sits is a gear that turns with the cylinder. The gear mates with a toothed pushrod that then connects to the switch itself. If the gear gets off by a tooth or two, you will end up with your problem.

Try this: Pull the ignition cylinder out and use a large screwdriver in the engagement slot and see if you can turn the screwdriver and get the sterter circuit to engage. If so, then that should confirm the idea that you're off a tooth or two.

I had this exact symptom years ago on my old 89 SHO when I replaced the switch in the parts store parking lot. I had to move its rack gear so it would mate with the right gear teeth and was able to get it back together correctly after several attempts. I don't know how similar the older column was with the 01's but it sounds suspiciously familiar.

 

My truck was running fine it is a 2008 f250 super duty 5.4l when parked sat for a few days and when I went to use it to move equipment around it would not start I have checked fuses and relays not finding any bad ones if I jump the solenoid it will turn over bit nothing from the switch none of my gauges are working nor any of my dash lights such as blinkers. But my blinkers are working on the outside. I am looking for any suggestions anyone may have.

 

Please start your own original thread in the PROPER section of the forum for assistance.