FJ40 Electrical: Ignition Problem

[Toler]

Hi Fellas,
I'm troubleshooting an electrical issue that I could use some guidance on - figured this is the best place to get some direction.
My rig - LS swapped 40 being managed by Holley Terminator X(running great since 2020).
Issue #1:
The switched power at the ignition suddenly stopped working. When I cycle the key through the ACC and ON positions, the dash panel that normally comes online is completely dead. That switched power also controls the Holley ECU.

Battery has a full charge - brake lights, marker lights and turn signals work fine. I've replaced the ignition switch and key cylinder with new ones, and checked and replaced all fuses and relays, which hasn't solved the issue. As a test to rule out the Holley ECU as the issue, I ran a positive lead directly from the battery to the soldered pin on the ignition switch at about the 1 o'clock position, and it powers the Holley ECU, primes the fuel pump and I can start the truck - as long as I hold that wire in place.

Issue #2:
When performing the workaround start as I just explained, the truck actually cranks when the key reaches the ON position, vs. the usual method of rolling it all the way forward to crank, then releasing it as it springs back into the ON position.

I'm wondering if my ignition was the initial cause, and that I wired it incorrectly when installing the new one(previous owner did not have the original 4 PIN connector in place for plug-n-play replacement), OR whether the actual cause is something else entirely.

I appreciate any insights and experience driven recommendations you guys may have. Also, I'm located in S. FL in case anyone in the area is interested in taking a look.

Thanks guys!

 

[peesalot]

The ign should not heat the solenoid power for starter and crank engine in the on position, it sounds to me like you got the main power into ign switch & the output from ign to starter switched.

 

[Engineer8000]

Maybe check your fusible link and associated connections.

 

[Toler]

I can crank and start the truck using the bypass explained above, so I think a fusible link issue would be ruled-out.
(I can't find any on the positive lines from the battery)

I'm getting 12v power to the ignition switch on the always hot wire. Just won't provide power to the switched power wire/pin on the ignition switch when the key is turned. Could the circuit be open someplace and causing this? I've also bench-tested the new ignition switch to ensure there's continuity when the key is being turned.

Scratching my head on this one.

 

[Engineer8000]

Your jumper from the battery, where on the battery? Are you measuring 12V on the WL wire at the ignition switch while attempting to start (cranking over the engine with the starter without your jumper)? What color wire on the ignition switch are you jumpering to? DMMs have very high input impedance (10 Mohm typically) so they draw very little current through any resistances in the circuit. It could be the voltage on the WL wire at the ignition switch is dropping to near zero when the circuit is loaded. Not enough to pick up the starter solenoid.

 

[45Dougal]

Sounds like a corroded crimp terminal on the ignition switch connector on the harness side.