Tom_K

1968 BB conv.
Did my switch just go bad?.
car turned off while driving- then turn back on (big boom out sidepipes)

Got it home and Car didn’t tune off with key ..
did amd 3rd try

i assume the key key switch is bad.
Is that correct. - this is a dash mounted key switch

if bad, is there any secret or issues replacing it?

Seams like a simple job.

thanks.

terrys6t8roadster

You do know about turning the key to accessory position, then inserting paper clip into small hole to extract tumblers? T

Tom_K

Hmmmm? No,
I am fairly new to the Corvette world.

How does that relate to getting the switch to work properly? or does removal via this method allow for inspection and fix?

carriljc

Also check the wiring around the starter. When my 68 had similar symptoms it ended up being the wiring down there. While fixing that I also discovered that I had an intermittent short in the starter solenoid which would cause the battery to drain.... I had a heck of a time finding that.

Tom_K

Just went through starter wiring, all looks good.

On the Ig. Switch, is it typically the key tumbler or the switch that fails?

Do I simply replace both?

Rescue Rogers

The switch would be the problem, not the key tumbler if it's not a short

scottjamison

Right. Replacing the tumbler will just give you a different key.
You will need to pull the front of the dash off to get to the switch from the back. It is kind of a PITA to get the connector on and off, but I did it and it worked.
THEN pull the tumbler out of your old one and put it into the new switch to keep the same key (Since the ignition and door keys are the same).
You could do it all in a day. Just be patient putting it back together to the panels line up nicely.

TimAT

IIRC, the tumbler has to be removed to get the nut that holds the switch in the panel.

scottjamison

Ah hah! You are right! I forgot about that

carriljc

You do NOT have to pull the front of the dash. Just remove the center bezel and can access everything from the center.

.... On my 68 the car was doing weird stuff like NOT stopping when I turned the key to off... You can reach in & disconnect the elec connector from the keyswitch from the center with the bezel removed

ronarndt

If your hands are normal size you can reach in without taking the entire dash off. I tilted the center panel (the part with the gauges) forward and reached in. The wiring connector that plugs into the switch may stick and be difficult to disconnect, since it has been connected and stuck fast for 50 years. Also, the threaded collar on the front of the dash that holds the switch in place is a PIA to get off and get back on. Do not cross thread it or it will never tighten properly. There is a specialty tool to grip the notches in the collar to remove it, but you can sharpen the tips of a cheap pair of needle nose pliers instead of paying $10 for a tool you will use only once. Don't forget to disconnect the battery or you will see sparks. Not fun working behind the dash, but it sounds like your switch is worn out.

carriljc

I was troubleshooting my switch, and when I disconnected the plug on the back and the car did NOT stop, then it was obvious that it was NOT the switch. You can try that once you get that center bezel out.
When the car did NOT turn off with the key, or even with the back plug disconnected, then at that point it was NOT the keyswitch. Might want to give that a check.....

Rescue Rogers

If I remember corectly, there is a special tool to get the bezel off if you are removing the whole thing. I think you can just unplug it though. I dont think it will shut off if you unplug it though, it will run if its still getting power from the alternator. Have you, a mouse, or the PO messed with the wiring at the alternator. I remember shutting off my battery cutoff switch that kills all the battery power to the entire car and the car still running. You can turn the key to run, (not start) and check the power at the coil, then turn the switch to the off position and see if the power stays or goes. Then disconnect the lead on the alternator, start the car and see if the car stays running when you turn it off. Are you still using the voltage regulator?

And yes the switch is easy to see with the center console partially out.

Tom_K

I got the new switch in - was quite easy by removing the upper center console. -It took about 10 minutes to remove.


With new switch in, the car will crank but it will not fire and none of the "ignition on pre-start bezel lights" go on .
It would appear that the ignition is not on. All fuses look in foot-well block are good.


this is the part: https://www.zip-corvette.com/68-igni...placement.html



When the original switch failed - car shut off while driving, I got it home then it took me a while with the key (on and off) to get the car to shut off.
When I went out the following day the battery was completely drained.

Now when I connect the battery there is a strong power draw, you can hear what sounds like a relay switching.
I left it connected for a little while and the wiper motor is now hot.
I disconnected the battery,

It was my hope that selling my vintage Fiat Spider and getting the corvette would eliminate the constant electrical gremlins.....
I know it's an old car but..... I do not want to spend the summer chasing this crap down.....

any Ideas? I do not know where to start. Hell, I do not want to start.

carriljc

Turn your key to on and turn on the wipers. Make sure they go thru a cycle and then turn the wiper switch to OFF and then let them "park" before you turn the key to OFF... hopefully that part of your switch is still working.
IF NOT, then just unplug the wiper motor until we get the ignition fixed.

I really think you got ahead of yourself by already replacing the ignition switch. No biggie though - now you have 2 switches so it's all good.

Here is what I recommend.
1. Disconnect or otherwise removed power to the wiper motor since your ignition switch is acting up.

2. Plug in the old ignition switch and see if the car starts, or if the symptoms are different from the new ignition switch.

3. Report back and we can commence troubleshooting.

I am suspecting (speculation really) that disturbing the leads behind the ignition switch altered what was going on.....put in the old switch and check.

Tom_K

carriljc,
I hooked up the old switch and let the wipers park.

The car fired right up and all appears normal.

What started this is - I was driving - normal about 35 and the engine stopped making power for about 3 second then it was back
about 20 minutes later same thing under acceleration, 5 seconds or so then back 5 minutes later cursing it happened and I determined that the ignition simply shut off.
It came back on in a few seconds, this time to a huge backfire, I was going about 60.

I drove the car home and when parking it, I could not get the engine to turn off. Turing the key did nothing. I fiddled with it a bit and it turning off.
The next morning the battery was drained.

Not that the Ig. switch has been removed and reinstalled it appears to work. So is it the switch or could something else cause the ignition to turn off?

Thanks for the assistance,

carriljc

Tom_K
hmmm... well, now we have a conundrum!!

I just re-read this and see that you have the old switch installed....hmmm....

QUESTION: Did you by any chance use the wipers on the drive when it failed? Remember that on a 68 you should let the wipers finish their cycle and park before you turn everything off.

Still should not affect the system as you mentioned so I'm a bit confused.... check the leads for the ignition switch behind the dash and recheck the leads in the bundle near the starter... really carefully check because this would annoying as hell if it happened again out in the middle of nowhere.
The leads around the starter get really hard and brittle as they get old. You could have an intermittent short, or intermittent open, or intermittent ground, causing your troubles. I think it would be well worth the trouble to disconnect the battery and go through and check all the leads around the starter. Clean, repair, replace, and reinsulate as necessary ---

Tom_K

carrlijc,

I have the center console out so this is easy. I have installed and tested both switches and they both work.
The wipers are a non-issue. I must have bumped the switch and started a cycle. Now that they are properly parked there is no issue.
Everything else is working normally.

I think the original switch is faulty. The issue I had with the car was it shutting off a few times while driving and then I could not turn it off with the key.
-had to go on-off on-off several times to get the car to shut down.

Is it possible that the original switch is simply getting real old and the contacts and sloppy causing intermittent failures?

I really appreciate the assistance

Having owned many vintage cars (mostly euro) and relying on many forums, I can say with experience that the Corvette group is the most engaged and enthusiastic!

carriljc

Tom_K
Well, for the situation that we're in I would just leave the new switch in and just be aware that if it happens again it is probably some of the wiring... either behind the dash, or down by the starter.

You can take your old switch and hook up and ohmeter and wiggle the key back and forth between terminal locations and see if there is some intermittent open.

That failure to turn off with the key is the problem I had . Just be aware --- you can always turn it off by putting it in gear, holding the brake, and dropping the clutch. (assuming it's a manual?)

I found my old post. It was an intermittent internal solenoid short .... it would also cause a constant battery drain (sometimes - remember it was intermittent). I also tidied up all the wiring around the starter and resoldered, heat shrunk, and protected all while I was at it. Here you go:
https://www.corvetteforum.com/forums...s-running.html

Tom_K

carriljc,

well.... it happened again
Diving at 45mph the car simply turned off
I could turn the key and it would start but the minute the key came off the starter switch the car shut off.
I eventually got it running, then to shut it off I had to hold the key hard left against the accessory side.
seams the key lock section could be too sloppy in the switch.