69 Dash Brake Light

[Kelly H.]

The brake light above the tach in my 69 is always on. I have the emergency brake console off and can see a switch that simply depresses when the brake it released. Not sure if that is bad or if I should be looking at something else? Any tips on diagnosing the problem? Thanks

[Joe L.]

Re: 69 Dash Brake Light

The brake light above the tach in my 69 is always on. I have the emergency brake console off and can see a switch that simply depresses when the brake it released. Not sure if that is bad or if I should be looking at something else? Any tips on diagnosing the problem? Thanks

Kelly-----


The "brake" light on the tachometer of 68+ Corvettes has TWO functions. First, and most obviously, it indicates that the parking brake is on or off. This is controlled by the switch attached to the parking brake lever. The first thing I'd do is to check this switch for proper operation.

The second function of the "brake" light is to indicate if an imbalance exists in the hydraulic brake system. That's because an imbalance can indicate a failure of one of the two separate braking systems used for all 67 and later Corvettes. However, it can also be caused by a failure of the brake distribution block and pressure differential sensing switch which is mounted to the frame below and to the left of the master cylinder. If the switch fails or if the switch becomes stuck "off-center", the light will remain on. Also, there can be an actual deficiency in one of the braking systems (like AIR in one of the systems) which can cause the light to illuminate and remain on.

Service instructions are contained in your Chassis Service Manual.

[Jim T.]

Re: 69 Dash Brake Light

Kelly if you are going to examine your emergency brake light activation switch the emergency brake console will have to be removed. Besides the screws you can see on the sides of the console there is a hidden bolt that screws into the steel console support/brace directly behind the rear of the console.
With the jack storage tray removed and reaching from the passenger side with your left hand over to to center of the compartment wall you should be able to feel the head of the bolt. If it is the original bolt, it is a shouldered bolt. The size is 3/8 or 7/16.

[Kelly H.]

Re: 69 Dash Brake Light

Thanks, I found the bolt and removed the console. Any way of testing the switch or do you just replace it? To be honest I can't see how the circut is "switched" The whole "switch" just moves up and down when the brake handle is moved?

[Joe L.]

Re: 69 Dash Brake Light

Thanks, I found the bolt and removed the console. Any way of testing the switch or do you just replace it? To be honest I can't see how the circut is "switched" The whole "switch" just moves up and down when the brake handle is moved?

Kelly-----


It's easy to check the switch. Just do a continuity check using a VOM with the switch button fully depressed and with the button in its free position.

[Jeffrey S.]

Re: 69 Dash Brake Light

Kelly:
Remove the brown wire attached to the distribution block switch. If the light goes out the problem is the switch. If it stays on it is the e-brake on/off switch. Also, check continuity to ground from the post on the dist. block switch. If there is continuity then the switch is off center as Joe suggested. If there is no continuity than, again, it probably will be the e-brake switch.
Jeff

[Kelly H.]

Re: 69 Dash Brake Light

Thanks guys, I really appreciate the help. If the distribution switch is the problem does that mean the brake lines need to be bled, there is a an imbalance caused by air in the lines?

[Joe L.]

Re: 69 Dash Brake Light

Thanks guys, I really appreciate the help. If the distribution switch is the problem does that mean the brake lines need to be bled, there is a an imbalance caused by air in the lines?

Kelly-----


It might mean that. Are the brakes otherwise "soft"? It might also mean that the switch just needs to be centered. As I recall, there is a procedure for this in the service manual. Another possibility is that the switch and block assembly needs to be replaced. You're in luck if that's the case. Reproductions and rebuilt assemblies of all the various 67-82 blocks are now available.

[Joseph K.]

Re: 69 Dash Brake Light

I believe it is caused by an imbalance of flow of brake fluid. In other words there is more flow to the front brakes or the rear brakes. This is caused by a leak in fluid in the front or rear system. I bled My brakes when replacing the entire system and it did not trigger. I would have thought it would have shown an imbalance then....

Joe

[Terry M.]

Re: 69 Dash Brake Light

Sometimes it does show an imbalance when bleeding the brakes, and sometimes not. Depends on the method of bleeding.

[Chuck S.]

Re: 69 Dash Brake Light

Thanks guys, I really appreciate the help. If the distribution switch is the problem does that mean the brake lines need to be bled, there is a an imbalance caused by air in the lines?

When the light came on my 70, the general cause was a system pressure imbalance as Joe described. More specifically, it meant a rear caliper was leaking due to corrosion in the bores, with resultant piston seal failure.

If the brakes have not been well serviced over the years, that sceanario is very likely. Be careful the caliper repair doesn't suck you into an uplanned restoration vortex.