Ignition issues

[PowderB]

I recently bought a 1975 Gmc k1500 Sierra Grande for 400$. The kid said the lock cylinder was bad and already had a new one to replace. Well problem is since i put the new one in the thing seems backwards. I have replaced millions of these things but this is a first. What is going on is, when you roll the key forewards in order to start the thing, it cuts the ignition off. When you roll it back to kill the ignition normally and lock it the thing starts. What do i do to fix this and make it work like its supposed to.

[ray_mcavoy]

Is it a straight or tilt column?

It sounds like someone installed the wrong ignition switch ... the electrical part, not the lock cylinder.

The rack & pinion mechanism that connects the lock cylinder to the ignition switch is different for a straight vs. tilt column. I can't remember which one goes which way right now, but one of them has the rack gear on top of the pinion so it pushes on the linkage rod when you rotate the key forward to the start position. The other has the rack gear on the bottom of the pinion so it pulls on the linkage rod when you rotate the key forward to start.

So to fix it, I believe all you will need is the correct ignition switch that matches the type of column you have. The electrical connectors should be the same, but since the switch orientation is backwards, you will have to twist them around the other way so they'll line up correctly.

[PowderB]

It is a non tilt type column.The rack seems to be on top but as of now the gear that moves it has popped out and is out of line with it. I dont have the knowledge about anything like that to take it apart further and repair/replace these parts.

[ray_mcavoy]

Replacing the electrical part of the ignition switch isn't that difficult. It is located on the outside of the steering column. But to make it inaccessible for anti-theft purposes, it's on the top side where it's tucked up inside the brake pedal hanger bracket. So gaining access to the switch involves unbolting the column and lowering it down away form the dash. Once that's done, it's simply a matter of removing a couple of screws to swap out the switch.

The gear popping out of position does complicate matters a bit. I think it's possible to put it back into place without having to do any additional disassembly though. I just checked a repair manual to refresh my memory, and yes, the straight (non-tilt) column does have the rack on top of the pinion gear. So you can probably use a small screwdriver or other suitable tool to hold the rack up while you slide the pinion gear back into place. The trick is going to be getting them aligned correctly. Since the pinion gear doesn't have teeth all the way around, getting it a tooth or two off will limit the travel of the rack.

[PowderB]

i did get the gear put back into its proper position. I turned the key to watch the rod to see which way it moves, and it moves down in order to start it. I have the switch in my hand and it moves up in order to start. I guess the ignorant guy put the wrong switch in possibly at the same time they wired up a push button ignition with speaker wire.

[PowderB]

good news is that the new switch i bought works like a charm. key works now like its supposed to. Thanks for the help, I bet now I can sleep good. Next problem to iron out is bolting up the throttle linkage and getting the nasty sticky stuff off the steering wheel

[bonestock72]

This post saved my bacon. Many thanks