Here's where I'm at - 1968 vert 327/350.

The turn signals work, both front and rear.
All the lights work, both front and rear.
The emergency hazards only work in the front.
The brake lights do not work

I pulled the switch, but I don't know how to test it. From a search I ran, it sounds like it can't be a fuse issue if the turn signals are working which they are.

Is it a safe bet that the switch is bad or are thre others possibilities I'm missing? Help, please

 

Maybe all your brake lights burned out at tthe same time.
If you've got an oum meter, just check the contacts with the switch on and off.

 

If you have removed the switch can't you now bypass it to make the connection and see if the brake lights come on?

 

Can't see why not. Bypassing the switch should complete the circuit and put your lights on. Would make sure I have a reliable source of voltage like a power probe to do this so you won't fry the wiring if you do have a short in the circuit, houstonvett

 

The brake lite switch sends power back into the TS switch to turn on the brake lites. If you bypass the brake switch and still don't have brake lites you have a bad TS switch or wiring to the switch.
Mike

 

The ohm meter buzzes until I move the brake switch back (in the direction the brake pedal would push it) then it stops buzzing. When I tested the wire, it did not buzz at all until I put the hazard lights on and then it buzzed each time the hazards would blink on. I hope this makes sense to someone.

When you say bypass the switch, how do I do that and what do I use? The wire just runs into the brake switch so I assuming I need to just complete the circuit and the lights should come on if it's a bad switch right? A test light would serve this purpose?

Thanks,
Q

 

You should have two wires to the brake switch. One (I forget the color code) will have 12 volts with the key off. Use a jumper wire or a paper clip to jump the terminals in the plug. This will send 12 volts into the steering column to the TS switch. Be sure to check all this with the key off. If you don't have 12v at the brake switch start checking fuses. If you do have 12v and no brake lites have someone wiggle TS lever and see if the brake lites flicker.

Mike

 

If the problem is, in fact, the brake light switch, is it still available in production??? I found an AC Delco part number - D862C but there's no picture so I don't know if this is right or not.

 

I just spent the last three hours jerking around with my '68s brake light switch, after following this thread. I got it working, and this is how.

My brake lights would not come on, but flashers and turn signals would. I pulled the switch (that was a bitch, but not near as bad as putting it back in), flipped the lever a few times, and the brake lights came on. Turns out, when the brake pedal is just sitting there, the switch needs to be set so the switch arm is pushed back (the switch arm rests against the driver side of the pedal shaft, not the firewall side). When you push on the pedal the switch arm goes back into its "relaxed" position, completes the circuit and turns on the lights.

Since your prior note says the circuit is complete when the switch is at rest, then your switch is probably fine. You just need to install it (the bracket is adjustable) farther from the brake pedal (so it can get to its relaxed position when the pedal is depressed.

Plug your switch back in, with it just hanging there, and see if the lights come on. If yes, the switch is fine.

After reading this thread I also thought I had a bad switch. Calling around mostly led me to the switches for the '69s and up. eBay has one for '68s listed, and it gives the GM part number of 1993446. My local Chevy dealer did not have any, and he said none of the others around did either.

Hope this helps.

 

I see NOS '68 brake light switches now and then. They generally go for around $60. For comparison, a regular plunger style brake light switch like every other car under the sun uses goes for about $6. I don't know whether they are available through GM dealers any more or not but I suspect, not.

Removing that switch is a major PIA. I was considering going to a conventional brake light switch and bracket. As a last resort, I opened up the switch housing and found that there is a brass bar that slides back and forth with the brake lever. The brass bar in my switch had worn to the point that it wore completely through and was in two pieces. I fabricated a new brass slider bar from some 1/8" wide brass sheet stock that I bought at a hobby shop. I reassembled the switch and it works like a charm. I saved the time and aggravation and cost of buying a new '68 switch or fabricating a bracket to use the plunger style switch.

 

Our local Canadian Tire which you don't have but our auto parts store has the exact switch as a general brake light switch. It is very cheap, forget the price the this universal switch is an exact replacement for our cars.

 

1. If fuse = good then there is an open in the circuit (switch, broken wire, burnt out bulb...)

2. If fuse = bad then replace (fuses get old too)

3. If new fuse blows then you have a power wire shorted to ground (have fun hunting that one down )

 

I think I'm going to try replacing the fuse first. I get a good reading on the Ohm meter when the switch is engaged so I think the switch is good. It was a PIA getting out

The turn signals work, but the hazards only work in the front so I think the fuse may have taken a dump without really blowing. The box has a lot of oxidation on it so maybe that's causing some interferance?

I hope it's something simple

 

The fuse replacement didn't pan out. It did, however, fix my clock

So here's where I'm at - The switch itself is good.

When I jump the brake switch connector, the brake lights still do not come on, but when I turn the hazards on, the front lights activate, but do not blink until I undo the jumper on the brake switch - then they blink again.

If I turn the blinkers on AND activate the hazards, the turn signal in back blinks at the same rate as the flasher so I'm not sure where to even start with this one

If anyone thinks it is somehow a defective TS switch, I found a dealer who carries them for the 68 camaro which is the same switch as we all know ($51.00)

Any other ideas???

 

i had a big problem with my 71' and the daisy chain grnd , ended up having to replace all of the housings , but not sure if you have turn sig , that it could be related to a grnd issue , remove one of the lens and attach gator clip to housing and then to bumper have someone apply brakes and see if you get anything

 

Remember on our cars if you step on the brake when the hazards are on it will stop them from blinking. This is normal.

 

So...

Fuse = Good
Switch = Good
Jumping the brake switch line does not make the brake lights come on
Hazards only work in front
Turn signals work in both front and back

Does the problem lie in the TS switch (more than likely, right???)

 

Before gettting into the TS switch replacement, disconnect the rear harness from the dash harness. The long rectangular plug is near the driver's side kick panel or maybe poked behind it. Once the rear harness plug has been disconnected, jumper a 12V line to the the pins that activate the rear brake lights. Look for the wires running into the plug that are yellow, green, and brown. The brown one runs to the rear running lights. Yellow to the left turn signal lights and brake lights for the driver's side. Green to the signal lights brake lights on the pass side. Check to see that jumpering either the yellow or green pins cause the brake lights to light. The hazard flasher works off of a different flasher unit than the turn signal.

You can also connect a continuity light to the plug on the dash light. Yellow and green wires again with the other lead of the light to ground. This time you're looking for the continuity ligtht to flash with either the turn signal or brake lights when connected to either the yellow or green leads.

If you still see the same as before it's probably the turn signal switch although these switches are pretty simple in design so I'm not sure what could be wrong here. My money is on a bad ground. Since the body of these cars is fiberglass there are many of them and when you lose a couple, the potential for lots of weird electrical stuff to happen is great.

I also want you to be aware of something I encountered with my car when connecting the rear harness. The bulbs in the rear housings push in and turn, but the wiring from the backside of the tail light panel also plugs in the the housing, and in turn contacts the light bulb. I found I had inserted the plug into the housing wrong and it wasn't making contact with the bulb properly, was shorting, and was basically causing really weird stuff to happen. In all my fiddling, I had also unknowingly pulled a ground wire from the connector in the rear. That also caused some weird things to happen.

Hope you get this sorted out. It can be real frustrating tracking down a problem like this.

 

This may be a stretch but...

In a box of parts that came with my vette, I noticed that a retaining plate, which is supposed to connect to the radio antenna was never reinstalled. This plate is about 8 1/2 inches long and maybe 5 inches wide - all metal. It has a ground strap on it which looks like it attached to the frame somewhere, but I'm not sure.

Could the absence of this plate cause the brake lights to not work???

 

That plate is what us radio types refer to as a "ground plane"....the plate will connect to the radio antenna coax "shield" and then most probably a wire to the frame and simulate the other half of a dipole antenna, well, sort of (others of my type!!, I am trying NOT to give radio 101 here )...we have fiberglass fenders...most regular cars have metal fenders connected to the frame and this coax shield is connected, well basically, to the fender, the surface of the metal body acts as this ground plane..if you install this plate, the radio reception in the vette will be "MUCH" better...as far as the brake lites....yeah, that's a stretch me thinks...