[Greg Reid]

The 'Brake' indicator lamp on the dash of my son's '78 Bonneville is staying on at all times. I think it's probably a problem within the parking brake light switch or wiring to the switch but I've been unable to locate it.
Any ideas?
I think it was member named "engineer" who has a '78 Bonneville. If you see this, maybe you know where the switch is located?

[455Grandville]

Check & see if the parking brake is just barely moved down, if you sneezed on my 80 Bonnie, it would move just enough for the light to go on -

[79GPrix]

I was going to say the same thing...I have a 79 GP and you can give the pedal a tap down and the light pops on.

[Greg Reid]

I'll check for something like that but I'll tell you, this parking brake is very tight. You know how some cars you can push it down with your hand if your working under the dash? Forget it on this one. It's jam up and jelly tight. You just about have to stand on it to set it.
This problem just started about a week ago and we've only had it for about a month..

[srercrcr]

The cables are probably seizing against their sheathing.
I purposely use my parking brake alot to keep everything working smoothly.
In fact, I just got an extra click on it when I engage it.

[Greg Reid]

But even if they are (and the may be) that wouldn't keep the light on would it? I'm assuming the light switch is under the dash somewhere, actuated physically by the pedal, and right now the pedal seems to be coming up as far as it can physically travel.

[iowapub]

Isnt there a wire plug-in attached to a copper spring-clip mounted on the e-brake assembly? A cam action will allow the spring-clip to make the electrical connection.

Remove the kick panel and the plastic panel under the steering column. Its waaay up there towards the firewall side. Unplug it or pull the copper spring-clip away. That should turn off the light.

Do you want inner door panels for a 4 door bonny? Brown cloth. Only have 3 though.......

[Greg Reid]

Thanks, that's what I was trying to find out. I really want to verify that it's e-brake related and not something wrong in the system. He's telling me that it goes out sometimes.
As for the doorpanels, thanks for the offer but they wouldn't go with this car....

[Greg Reid]

Just to let you guys know, my son wasn't giving me all the details of the problem here. I don't think it has anything to do with the parking brake switch. More likely a problem with the centering valve. I went out and drove it and when I gave the brakes a hard stab, the light went out.
The master cylinder may need bleeding. I'm not sure about what causes that.
Thanks for the suggestions.

[Tin Injun Tom]

Just stumbled onto this thread. Greg, I'm quite sure it is the 'centering valve'.
My '78 Grand Am had the light come on when the fluid got so low, the pedal went way down. Rear wheel cylinders had been leaking for a long time. I had to crack the fitting loose (to the front brakes) at the valve where the switch is, to get the light to go out.
You may not have to bleed the master cylinder. Check the rear wheel cylinders first.

[Greg Reid]

Tom, I looked for any sign of leakage on the insides of the rear tires and saw nothing. If I can get my son out of it long enough at the same time that I feel like working on it, I'll try bleeding the system.
The brakes feel ok but the light comes on intermittently. Mostly, it stays on.

[Tin Injun Tom]

Wheel cylinder leakage doesn't have to be severe. Mine just seaped slightly. I hadn't checked the fluid level in ages, so one day the pedal travel got down far enough to trip the switch. In fact, I never bothered to replace the wheel cylinders. Just filled up the master with fluid. The brakes worked fine after that.
Seems like the problem with your Bonne must be down stream of the pressure differential switch. Usually you have to open a bleeder on the opposite end of where the problem occured to reset the switch.
Oh, and have someone push the pedal down to the floor so the plunger inside the switch will move back to the center.
Intermitant seems a bit odd. I wonder if there might be alot of brake shoe travel in the rear plus front pads very used up. Will be interested to know what you find.

[Greg Reid]

So bleeding the wheel cylinders wouldn't be a waste of time then...Right?

[Tin Injun Tom]

You got me while I was editing that last post. No it wouldn't be a bad idea to bleed them. If just to get fresh fluid into the system.

[Greg Reid]

I'll let you know... and thanks for the advice.