Problem. When I pull my headlight switch to the running light position, I have tail lights but no brake lights. When I pull the switch to full on (headlights) I get headlights but still no tail lights and nothing when I apply the brakes. Turn signals work fine both front and rear and so does the interior light. Any thoughts? Headlight switch maybe? I really thought that I had this licked. o No:
So I removed and disassembled the headlight switch. Is very clean inside and everything looks to be intact. Nothing was green or burnt. Do these things even go bad when so clean inside? After inspecting and reassembling everything it seems to function fine on the bench. I just tried a jumper between the red wire to the to the other spades on the plug. I got power to everything but the orange and the violet wires. The wiring is dead stock, and has never been cut anywhere that I can see, but I'm still not getting power to the dash illumination lights, the plug for the brake switch and obviously my brake lights. How could I be getting tail lights on the park setting but nothing out back when the switch is full on? I get headlights, running lights up front and blinkers as well. Turn signals work fine in all positions. I have a ghost.
Rotating the light switch stalk will dim and brighten the dash lights. Maybe you have it in the full dim position? Grounds are a major source of electrical problems. Look at the grounds at the rear bumper and at the headlight switch itself. You should buy a Buick Chassis manual for your year Buick. They are available used on E Bay, in Reproduction form, and even on CD ROM. You have checked the fuses, right?
Have been turning the dimmer switch will much distain. Nothing. I had dome light yesterday, pulled the plug to inspect, replaced it and now nothing. Had it working though. I now have tail lights in all switch positions, but still no power going to the leads for the brake lights. Still no dash light or high beam indicator, though the high beam works. I have a factory wiring diagram that I uploaded from the web, but have actually found flaws in it regarding the brake switch wires. It's just a misprint where they turned one of the blue wires into brown mid-path. I figured it out, but it had me scratching my head for a while. All the grounds at the rear seem fine as I have all other lights, including backup lights. My dimmer switch is a little fickle but when it's working it does it's job. I've ruled out everything (i think) that isn't ground related or a dead wire, though I can't imagine that a wire would just short. I haven't found anything burned. There is a tiny 3A fuse sitting at the top right of the fuse block that traces to the rheostat side of the switch and around to the instrument lights, and everything else that can be dimmed. Everything else in the block works fine, but can't get power to that fuse. Could it be a fried switch/rheostat? Would a burned bulb in the circuit emulate a short? Could it be that easy? Ugh, my head.
A '61 Special is a different animal. The brake lights are controlled by a hydraulic switch mounted on the master cylinder. The switch is closed by hydraulic pressure when the brakes are applied. You mentioned that the turn signals work, if they blink then the 20 amp "DIR SIG" fuse should be okay. Never hurts to visually inspect. If you have turn signals and running lights, those two outputs tell you a lot about the car before you even grab a tool. The wiring from the switch and to the lamps are good. The stop light switch is mounted on the front of the master cylinder, just above the supply line that feeds the brake "junction" box. I'm not sure where you got the wire colors but the factory manual shows Dark green w/white tracer for the left turn signal/brake light. Light green w/white tracer for the right turn signal/brake. If you do not have power at the 3A fuse in the fuse block: Verify you have 12v (not just power a test light) at the 14g reg wire feeding the headlight switch. Make sure the headlight switch knob is rotated fully counterclockwise, this is full on. (To dim the lights, turn it clockwise) With the switch in the park or headlight positions, you should have voltage to the smaller white wire on the forward most connection. (that white wire feeds the 3A fuse). I'm confused as to what plug you pulled and inspected when you had a dome light? The plug at the headlight switch or the plug in the harness?
I had a dome light and then pulled the plug at the headlight switch to check the rheostat function. circuit went dead after plugging it back in. Was referring to the blue brake switch wires at the connector where it actually hooks to the brake switch. Shouldn't one side of that be hot and the other not, until brake pressure closes the switch? I traced all of the turn signal lights (you are correct about the dk. green, lt. green w/white) and they are fine. Have checked white wire leading to fuse block w/dimmer turned in both directions and got nothing, but will do it again. Have been using a test light to run everything down, but will grab the multimeter in the morning and see if there is any kind of significant difference in voltage. Sounds to me like it might not be getting anything to the rheostat (broken maybe) but it looks good, even under a magnifying glass. My main concern now is the brakes and why that/those blue wires have no juice. Thanks too ALL for the advice. Will take a more discerning look in the morning and post my results..., or lack thereof. You meet the nicest folks when beating your head against the roof of your Buick. Thanks again. -Steed
Update. Checked red wire at headlight plug w/multimeter. 12 volts spot on. Also took a look at the rheostat wire and 3A fuse in block. No love at all. I do have continuity from the wire running from the headlight switch plug to the fuse block on both sides of the fuse. I didn't check for continuity from the dome light to the block, but the bulb is fine as I get continuity across the clips. Bad rheostat in switch? Just ran jumper from hot to the dimmer fuse at block and got voltage on both sides of the fuse, but when I pulled the headlight switch to the fully on position, it cut the power to the block. I thought that simply hot wiring that circuit with the dome light turned on at the switch would make the danged thing light up, but nothing. No dome, no dash lights. I do have to say that as frustrating this is, I am enjoying the process and now that it's gotten "personal" I am motivated to figure this out. Any thoughts? o No: Thanks in advance! -Steed
Apply hand to face, SLAP VIGOROUSLY. Headlight switch wasn't grounded to dash panel. Amazing. On to my brake light problem. Off topic of forum but does anyone know where I can get a rebuilt master cylinder?
Glad it was something simple. Try Kanter Auto products. www.kanter.com There site isn't working at the moment, I would give it a few days. You might have to send it out to be rebuilt. Do you have power brakes? Ebay search turned up these two. LINK #1 LINK #2
Thanks, I'm getting there. I have been trying Kanter's sight for some while, not sure what's going on there. Think I will end up sending it out to somebody, is leaking into the interior of the car. Single stage, manual drums. Got to looking at it when I was playing with the brake switch. It's ugly and should be fixed by someone who can return it in a better visual state, aside from the internals. Thought about upgrading to a two stage unit, but I don't have any real aspirations regarding speed, so I'll stick with the stock brakes.
