Wacky ignition switch behavior

[IndyAnne]

I love this forum for all the knowledge here. Thanks in advance!
Problem: it has been raining, don't know if it has anything to do with anything, but...
I picked up a couple of neighbors' trash to take to the dump. Nothing out of the ordinary happened until I got there and turned off the ignition to get out and unload. Truck would not turn off.

Stopped by auto parts store because my go-to guy was closed (Pat Lorber at Apex in Greenwood). Only learned to pull the 30 amp fuse for the ignition EMC ? to stop the engine. When I got home, turned the switch off, but noticed a whining sound from near the gas tank. Scary, so I disconnected the neg. battery line. I put one of those quick disconnect devices because I've been preparing to put in a new stereo and try to troubleshoot the lack of courtesy lights including the dome light.

When I d/c'ed the neg battery, the fuel tank sound stopped. Then I reconnected the neg battery cable. It was still daytime here around 7 pm

later, I went out to get something out of the truck and the dome light was on!

And, coincidentally, the temperature gauge indicates the engine is running hot.

I've been browsing the forum and other sites, not getting much specific info.

Would replacing the switch be the fix? I know the current switch is an after-market replacement because I can't get extra keys made without paying a lot to a locksmith for a "chinese made" (pardon if I'm insulting anyone) key duplicate.

Are the engine temp gauge reading and the overhead light suddenly working possibly coincidental?
Anyway -- why would the overhead light suddenly work when the ignition key will not kill the engine?

[ChevLoRay]

Dizzy.....dizzy......I'm getting dizzy.

This is an interesting delimna. I hope someone with some electrical experience will join in, but in my opinion you have several issues. It sounds like whatever you did to kill the engine didn't take the power away from the fuel pump.

Heck, if I didn't know better, I'd think you're having a problem with your computer.

What you didn't tell us is what year truck you have and how it is equipped. If it is a '96 or newer, a trip to a scan tool is going to be easier to help than an '88-95. Give us some more info and that will help us help you.

[jb1016]

Her truck is in her siggy. And I agree, the whining sound is probably the fuel pump...why would it still be running with the engine off? Weird, wild stuff...

[IndyAnne]

Yes, truck details are in sig.

More clarity: I can turn off and lock the steering wheel and remove the key, engine keeps running.

Instrument cluster gauges continue to work, with elevated engine temp.

Heater/air opens upon starting the engine, and closes when the key turns to OFF and LOCK.

All of a sudden, overhead light is working when it has never worked before.

Fuel pump will continue to run when the key is turned to OFF/LOCK.

Removing IGN fuse (30 amp) is not enough. Have to d/c neg. battery cable also.

That's as far as I've gotten in the differential diagnosis. Chilton and Haynes give good illustration on replacing the lock cylinder, but is that enough?

I'll get the low voltage tester and the multimeter out in the morning and see if circuits are flowing ok, try to narrow down the options.

Previos owner installed the current cylinder from auto parts big box store. Maybe Truck Parts Plus will have a GM replacement I can try.

Other suggestions? I'm not ready to pay a shop's labor cost yet, if I can figure it out would be great.

[ChevyTech]

The ignition switch is an electrical part and is separate from the ignition key cylinder.

The ignition is mounted on the upper surface of the left side of the lower steering column. The high beam headlight switch shares mounting screws with the ignition switch.

A rod going down the steering column connects the ignition lock cylinder mechanism to the ignition switch.

When your replace the ignition switch, your will need to remove the high beam headlight switch. If you do not tape the high-beam rod that goes up the column in place, it will usually fall out. It is not a big problem, but it must be installed correctly for the high-beam switch to function.

Also notice the ignition switch and high-beam switch positions are somewhat adjustable because the holes are slotted.

If I were working on it I would unplug the ignition switch electrical connecters and see if everything turns off.

[IndyAnne]

ChevyTech,

Thank you for explaining the differences. I wish I had a photo, but your directions sound very clear. I'll let you know how I do with getting everything apart. I'll take photos and post those as I go along.

Thanks again.

Originally Posted by ChevyTech

The ignition switch is an electrical part and is separate from the ignition key cylinder.

The ignition is mounted on the upper surface of the left side of the lower steering column. The high beam headlight switch shares mounting screws with the ignition switch.

A rod going down the steering column connects the ignition lock cylinder mechanism to the ignition switch.

When your replace the ignition switch, your will need to remove the high beam headlight switch. If you do not tape the high-beam rod that goes up the column in place, it will usually fall out. It is not a big problem, but it must be installed correctly for the high-beam switch to function.

Also notice the ignition switch and high-beam switch positions are somewhat adjustable because the holes are slotted.

If I were working on it I would unplug the ignition switch electrical connecters and see if everything turns off.

[ChevyTech]

You're welcome!

This photo is not of a truck but the switch mounts the same.
Your 1988 truck will not have a park lock cable.


Here is a link to a photo if they do not allow hot linking:
http://shbox.com/1/ignition_switch.jpg
I can't get my saved link to their site to work.
Edit: Here is a link to part of thier site the has some very useful information, and should lead to the source of the photo above.
http://shbox.com/1/4th_gen_tech1.html

If you want more photos let me know if you have a tilt column or not.

[ChevLoRay]

Well, I said I was getting dizzy....guess that made me miss the sig data. Sorry.

When ChevyTech speaks, er, writes....you can take it to the bank. Glad we got some replies that offer promise.

[IndyAnne]

ChevyTech -- great photo!

So, today, I went to pick up the ignition lock cylinder and the switch, and steering wheel puller, intending to start with the least complicated removal (the switch). I got home and put the IGN fuse back in and reconnected the neg battery line.

I forgot to mention, I have the driver side door panel off, and most of the dash, in the process of troubleshooting. Therefore, as part of this mystery (to me), the overhead/dome light that has never worked before was on because the driver side door switch was not being pressed in by the door panel, which means the circuit was closed, in electical-ese, right? So the light would shine until the lamp burned out or the battery totally discharged. This was encouraging, because the courtesy lights have not worked until this event.

When I started up and moved the truck closer to my tools, turned off the key and removed the key -- the engine stopped, no other sounds remained such as the fuel pump.

I started right back up and took the parts and the puller back to the store.

Could it be the computer, as originally suggested by ChevLoRay?

What on earth is going on?

Maybe the battery disconnection for a couple of days reset something.

Still, I think I do need to keep troubleshooting this switch. Too much is missing in the ignition switch related circuit. Something going on. I'll keep an eye on it.

Again, that is a great photo, I knew exactly what to look for.

Originally Posted by ChevyTech

You're welcome!

This photo is not of a truck but the switch mounts the same.
Your 1988 truck will not have a park lock cable.


Here is a link to a photo if they do not allow hot linking:
http://shbox.com/1/ignition_switch.jpg
I can't get my saved link to their site to work.
Edit: Here is a link to part of thier site the has some very useful information, and should lead to the source of the photo above.
http://shbox.com/1/4th_gen_tech1.html

If you want more photos let me know if you have a tilt column or not.

[IndyAnne]

Hey, Ray, yes, I'm dizzy now. As I responded to ChevTech, there was a mysterious case of healing by ignoring today. I put the fuse back in, connected the battery, and everything was normal, including the mysteriously now-working dome light. I'll need to keep an eye on it. I'll try to get some lamps into the rest of the courtesy lights to see if all are working now.

So, the computer was your first suggestion. Does this sound compatible with your experience with the computer's misbehaving? Interesting...

Originally Posted by ChevLoRay

Well, I said I was getting dizzy....guess that made me miss the sig data. Sorry.

When ChevyTech speaks, er, writes....you can take it to the bank. Glad we got some replies that offer promise.

[ChevLoRay]

With the battery disconnected, whatever codes had been set were deleted....especially after 2 days.

It takes a specific number of events to set a code. You may find that the situation reappears after that number, whatever it may be. There are people who "know" what that value is.

So, does that all point to the computer?

Stay tuned for another exciting chapter in......"Wacky Ignition Switch Behavior"...

[IndyAnne]

Oh, good, something to look forward to...

Originally Posted by ChevLoRay

With the battery disconnected, whatever codes had been set were deleted....especially after 2 days.

It takes a specific number of events to set a code. You may find that the situation reappears after that number, whatever it may be. There are people who "know" what that value is.

So, does that all point to the computer?

Stay tuned for another exciting chapter in......"Wacky Ignition Switch Behavior"...

[ChevyTech]

Originally Posted by IndyAnne

ChevyTech -- great photo!...
… Again, that is a great photo, I knew exactly what to look for.

Thanks!
Glad it helped you.

Originally Posted by IndyAnne

Could it be the computer, as originally suggested by ChevLoRay?

The ECM on a 1988 pick-up does control the fuel pump relay, but the engine should shut off with the key regardless of any problem the ECM is having.
Note: It is normal for the fuel pump to run for a few seconds after the truck is shut off.

You said you were preparing to put in a new stereo. I have traced down problems, with circuits being powered when they should not be, by the wiring done to install aftermarket stereos. It is important that the always live power for the memory in the stereo and the power supply for operation of the stereo do not get mixed up or connected to each other. Also make sure the wire to dim the display is connected correctly.

I would also pay attention to how it feels as you turn the key to start it and shut it off to see if it does not feel right,

[IndyAnne]

ChevTech,
You asked:

>>If you want more photos let me know if you have a tilt column or not.

I do have the tilt column.

And, in checking out the wiring for the stereo, I will get back to you about that if it's ok. I have the Chilton and Haynes books with the circuits, and a sheet that identifies the correct colors of wires that came with the original stereo system. As far as those books go with circuits, I'll be ok, but, I know they don't get into specific components and where they are located. That's all part of my learning curve -- like climbing Pike's Peak with my eyes closed :-)

The wiring has been quite messed up. I've removed a bird's nest of after-market wires from under the hood with connections to the alternator and the battery. There is a plate of spaghetti in the cab inside the dash, with lots of wiring clipped in all sorts of ways, hanging loose, but I haven't identified what's live and what's not. With the carpet out and the interior trim all removed, I can see where amps and woofers and such were bolted into the sheet metal of the floor, walls, and frame of the cab. Poor thing.

Come to think of it, perhaps all the broken glass chips I'm finding inside, and every time I open the door on the driveway, maybe someone broke in and stole a previous owner's system. It looks very careless and hastily done to me.

My stereo is not going to be one of those big loud systems, just a simple tuner connecting to the four speakers, that I also have to replace, using average 4x6 speakers. It has a CD player, but I expect I'll mostly be plugging in my iPod when I'm not listening to good ol' FM radio.

A mechanic at the salvage store helped me identify the after market wiring under the hood, but I have not yet tried to label everything that should be there for the stock stereo system. I'm hoping I can follow the schematics and keep everything in order when I get to that project.

Thanks for anticipating those potential disasters!

I'm not going for an Overhaulin' kind of outcome here, just want a safe and comfortable yard-working truck that will haul the Airstream to the parks.

I don't even know yet how the engine and transmission will handle towing the Airstream, but that's going to be another thread ...