68 Wiring Problem

[Jerry G.]

I'm a straight axle guy, but I just bought a 68 that I'm having a wiring problem with. It first had brake lights, now nothing. Turn signals and flashers worked, now no flashers. Left front signal not flashing but rear does. Just the oposite on the Right side. Right rear works, but not the front. Dash indicators doing the same thing. Both worked, now just one. Brake light fuse OK. Bad ground? Bad flasher? Are they tied into each other somehow? It's driving me crazy, and that's a short trip. Thanks in advance.

[Wayne W.]

Re: 68 Wiring Problem

Check all grounds and all bulbs and sockets. Any one bulb that goes out will cause that side to quit flashing. The corresponding front or rear will come on but not flash.

[Harmon C.]

Re: 68 Wiring Problem

The grounds at each tailight housing are a common problem. If the studs are rusty they break easy when you try to remove the nut to fix the ground.
Lyle

[Jerry G.]

Re: 68 Wiring Problem

Thanks, I'll check the grounds. I forgot to mention that when the headlights are turned on, all four tail lights are on also. Go figure. I don't know how all four work if one of the grounds is bad. Are they on another ciruit?

[Wayne P.]

Re: 68 Wiring Problem

Sonds more like it's in your turn signal switch.

[Jerry G.]

Re: 68 Wiring Problem

Thanks Wayne. So the brake lights are wired through the signal switch also? As you can tell, I'm certainly not an electrical expert.

[Jim T.]

Re: 68 Wiring Problem

Wayne I was just reading the package of a heavy duty flasher I have not used. It states "Warning: If one or more turn signal bulbs fail, a heavy duty flasher will continue to flash the remaining bulbs. Since bulb outage is not indicated, it is recommended that your signal system be frequently checked for bulb failure." A 68 Corvette has 4 rear tail lights and 4 stop lights, so a left or right turn signal operation will illuminate two left or two right turn signal/stop light bulbs. This 68 may have a heavy duty flasher to operate the turn signals. The hazard light flasher will have to flash all four tail lights. I just checked my 68's owner manual quickly and did not see what the actual flasher requirement is. Almost want to remove a front left parking light/turn signal bulb to see if the rear two left turn signals will still work and if not use the heavy duty flasher and see what happens.

[Jim T.]

Re: 68 Wiring Problem

Jerry your 68 has a separate fuse for the taillamps, separate fuse for the stop lights, and a separate fuse for the turn signals.

[Jim T.]

Re: 68 Wiring Problem

Jerry activate your hazard flashers and see what flashes. The turn signals has it own separate flasher and the hazard flasher has it own separate flasher

[Terry B.]

Re: 68 Wiring Problem

One more thing. I had a similar problem on my '68. I had a connection problem with the fuse. Corrosion had built up over the many years. Since you said this was a recent purchase, I'd take all the fuses out (one at a time) and lightly sand the ends of the fuses and and use a finger nail file on the fuse bock contacts. Worked for me.

[Jerry G.]

Re: 68 Wiring Problem

Jim. I had a blown fuse on the flasher side. I replaced it, but they blink real fast. The turn signals are still the same. L rear, but no front. R front, but no rear. The previous owner told me he had replaced the turn signal cam switch. He did, but I found that he spliced the new switch into the old plug-in. Why? I don't know unless it's hard to feed it through the column. I'm going to replace it, but I'm not sure that it will fix the brake light problem. I still don't have brake lights, but the lights work when the headlights are on.

[Jim T.]

Re: 68 Wiring Problem

If the left rear blink, that verifys the bulbs on the left have good stoplight and turn signal filiment. It also verifys that your turn signal flasher is OK if it is blinking bulbs. With number of bulbs that have to blink with the hazard flasher switch on, two in the front and all four lights in the back, and yours blinking real fast, you might need a heavy duty flasher. Do all lights blink fast, the L/R fronts and all 4 L/R rear? If so all the bulbs are good. The lights that work in the rear when your headlights are on are tail lights not brake lights or turn signal lights. To bad the previous owner did not take the time to correctly install a new turn signal assembly so the wired plug in would just plug in. With all the lights that should blink activating the hazard switch, and only some lights working with the turn signal the previous owners wiring may be where the problem is. You might be able to buy a new turn signal switch from a local auto parts store. Some GM cars use same turn signal switches. Do you have telescopic steering wheel? The brake light switch for 68's is a one year brake light switch from what I understand. It used to be available. Since the previous owner did some work on the car I would sure check out all the connections at the brake light switch and test the power to and from the unit during activation at the switch. Luminated test light is inexpensive to purchase.

[Jerry G.]

Re: 68 Wiring Problem

Jim. I replaced the flasher for the signals. Left side is working OK now. Left front, rear and dash indicator are working. Right front and dash indicator working, but not the rear. I replaced all the bulbs in the rear. Still no brake lights. The brake switch is 68 only. I disconnected it yesterday and jumped across the feed wires, but they still did not work. There's a resistor with the switch that I did not use on the jumped connection so I'm not sure if it makes a difference. When I bought the car last week, the brake lights did work. I'm hoping that replacing the turn switch will fix it, but I don't know if the brake lights are tied to it or not. It does not have telescopic. I did not know it might be available over the counter. Jerry

[Jim T.]

Re: 68 Wiring Problem

Jerry glad to hear all turn signals are working except the right rear. Does the right rear work when the hazard switch is activated? The resistor you mentioned is to keep noise out of your radio when the brakes are applied. I don't know if your switch would be available over the counter, O'Rileys had one for my 70 a year ago and it was also available as an AC Delco part, 69-76 Corvettes without tilt/telescopic had the same part number switch. The old part number for yours from a 1981 GM parts book lists the 67-68 turn signal switch #5698520. Hope you get lucky. The 68 only stop light switch with lever is #1993446 from the same book.

[Jerry G.]

Re: 68 Wiring Problem

Jim. Neither side works with the flashers on. Just the front and the dash indicators. I orderd a switch this evening. Hopefully that will solve it.