68 Dash Lights

[Kurt B.]

While idling the engine to warm the car up a bit, (it is cold here in New England these last few days,) I turned on my parking lights and all was well when all of a sudden the dash lights went off.
Parking lights, front and rear as well as the interior dome light when turned to on position, work fine but all gauges are dark.
What happened?
Thanks in advance,
Kurt

[mike valliant]

Re: 68 Dash Lights

Ken
There is a good possibility the head light switch
rheostat has failed.
Mike

[Jim T.]

Re: 68 Dash Lights

Kurt agree with what Mike said. The function of turning on the interior lights manually with the light switch and the dash lights inoperative are indcative that the spring looking resistance wire in the light switch has burned into not permitting electrical current to pass from the source to the end of the spring like wire. One good thing new switches are still available. Another good thing about this failure, your Corvette can still log some winter driving. I replaced my original 68's light switch because the part of the switch when it is rotated that slides across the steel spring adjusting the brightness of the dash lighs became loose and was not making enough positive contact to always illuminate the instrument lights.

[Jack H.]

Might be the HL switch...

but it could be something else. A 'safety' feature of electrical system acts to switch off the panel lamps when you have an electrical overload situation that would leave you driving WITHOUT rear illumination. You might have an intermittent continuity problem with your rear wiring harness...

[Kurt B.]

How remove HL Switch

Is there a relatively easy way to replace the headlight switch?
I have an a/c car so I cannot even get close to the switch from the bottom.
Must the steering wheel and dash and gauges come out?
Thanks
Kurt

[Jack H.]

No...

If you're clever and have small hands, you can R&R the HL switch without dropping the column and fully pulling the instrument cluster. The cluster will move outward on the column maybe an inch or two and then demonstrate 'reluctance' to move any more rearward. It's being stopped by two things: (1) the steering column and (2) a clip holding the wiring harness to the cluster between the speedo and tach.

Attempts to FORCE the cluster further rearward can trigger significant damage! Like the harness clip 'sawing' into the harness itself... DON'T do it!

But, with just an inch or so of clearance, it's possible to reach around the back from the side and get your finger on the HL knob/rod release button. From there, it's a matter of gymnastics to move the HL switch out of the cluster to swing freely on its wires and vac lines where you can do the R&R job from below the instrument panel.

The 'rate breaker' shop mechanics can execute a replacement of the switch in about 5-minutes flat. But, then they'll got a LOT of practice that the novice weekend warrior mechanic lacks....

[Kurt B.]

Thanks Jack,

I think I will wait until things warm up a bit as everything is quite brittle with the very cold weather. I don't want to do more damage in the process and have something else break or snap due to the cold.
I think I read somewhere that the switch is still available from GM. ??
Kurt

[Chuck R.]

Re: PLay it safe Kurt

If you don't already disconnect power when the car is going to be dormant, I think I'd kill power to the car now until your ready to work on it.

I wouldn't trust "potentially" funky electrical components (especially anything with a ballast or reostat)to be left un-watched for an extended period of time still powered up. Crap happens.

Just the nervous Nelly in me Kurt,

Chuck

[Kurt B.]

Good idea Chuck Thanks *NM*