Help Wiring Ignition Switch 1985 f150

[ylidk]

Hey all, I've been fighting with some wiring here and want to get some feedback. So the situation here is the ignition cylinder is jammed, and I haven't had luck of removing it to install a new one. Even if I did manage that, the actuator rod is missing, though I could shape a small rod to take the place of it. Instead, I decided I would force the ignition switch into the RUN position at all times, and wire in a starter button as well as cut the battery wires going to the OEM switch, and wire an aftermarket ignition switch to the battery wires. The hot end of the battery wire to the BAT terminal of the Aftermarket switch, and the battery wire going to the OEM Switch to the RUN position on the Aftermarket switch. That would give me something like this drawing, I believe:



Does anyone see any faults with this? I wired it up this way just last night and the lights wouldn't come on and the truck wouldn't start. Maybe I just put the battery cables on too loose and there wasn't a good connection, because this seemed like it would work to me. Thanks!
jgalley is online now Report Post

 

[Curious Hound]

If I understand you correctly, it sounds like your idea should work. Once you put the ignition switch in the run position, you will want to find a way to keep it from slipping out of position.

Looking at this diagram (upper right corner), it appears that there is some minor function in the ABS and instrument cluster that is normally grounded when you turn the key to "start". Without a lot more digging, I'm not sure how important that is. It may just be a lamp test function.

 

[RonD]

Can you pull the wiring connector off the ignition switch?
Maybe install a new switch and rig it so you can select OFF, RUN and START

Generally there is just one FUSED 12volt wire from the engine bay to the ignition switch, but it may be connected to 2 or 3 places on the switch

And generally there are 3 to 4 12v OUT wires on the switch.
1 wire will be ACC power, only radio and inside lights have power, no dash warning lights, no engine 12v power.
RUN will have a few wires and including ACC wire, engine 12v power and dash lights

START position often disconnected ACC and Dash power, leaving only engine power, giving full battery power for starter motor.
START position in 1985 may also bypass Coil Power resistor, giving Coil a hotter spark for cold engine startup.
Installing a STARTER Button for use in RUN position will work but won't give you the hotter spark for cold morning, which may or may not matter, and can be dealt with if it does

Brake lights shouldn't run thru ignition switch?
Neither should head lights

These were powered separately using different FUSED wires