Hey all...I've read post after post which has taught me a lot about wiring and further shows how much of a pain it can be. My problem is that all of the sudden I have no brake lights. Turn signals work and I have lights when my headlights are on. Wiring seems fine...all connections are good. Fuses are also good. I have also noticed that when my headlights are on, my signal lights blink slower and flicker a little. This doesn't happen when the headlights are off. So as for my brake lights, could this be the brake light switch at the master cylinder? I'm kind of at a loss right now. Thanks for any help!
could be that brake switch. you can check it by shorting the two terminals, if the brake lights go on then, the switch is probably bad.
years of rust and paint can obscure the ground path. I had to run ground pigtails on my ElCamino due to a similar problem. check the switch first though
only on the rears , fronts do not go thru the brake circuit , I have had this problem come in and the guy said the signals worked but not the brake lights but he didn't bother to check the rear turn signals , just assumed they worked because they clicked and they clicked slow too ( not enough draw to heat the element in the flasher can ) . both of the back lights the brake/turn element were burned out ... other wise check your brake switch to see if its working .
I am now thinking signal light switch as well. I took the car out this morning and my buddy behind me noticed that the brake lights worked briefly when I made a hard left with my blinker on.....so,maybe the switch or a wire in the column. I have the overhaul manual and am looking at removing the steering wheel and stuff..doesn't look too bad on paper...how about actual experience? Thanks everyone for all the help
did you test the brake switch? I only say that, because it's usually a good idea to try the simple things first....and the symptoms you have make it seem like the brake switch is at least 50% likely to be the problem.
if the brakes lights worked breifly the brake switch is more than likely the problem not the turn signal switch ..
Just came from my shop and removed my taillight buckets and added a ground from the bucket to a ground on the frame because when I stepped on the brake pedal with lights on and the taillight would go out with no brake lights coming on. The ground worked.
Just fixed a 2002 Z06 corvette with no headlights..bad ground connection at the battery terminal. My guess would be check fuses and grounds first.
Squirrel.....I have a dumb question, but I suppose it's how you learn....you mentioned shorting the two terminals....I'm just not sure what you mean. Sorry to have to ask
Jump from one terminal of the switch to the other 1951Merk Small jumper wire or something metal... that's what he meant I believe... And the reason your turn signals slow down a bit with headlights on is the flasher relay.. (round thing) may be old, or not heavy duty enough, But normaly with this issue I have always found that the tail lights or parking lights are not getting a good ground, causing a little bit of voltage bleed over through the brake light filament circuit not allowing the field to drop completely when the turn signal flasher tries to drop and then come back. Take every ground at the rear and on parking lights loose.. clean with sand paper right under where the ground attaches and clean the terminal also that is being grounded.. you will be amazed how much one little bit of surface rust or oxidization on a terminal can cause you complete hell with lighting etc.
A bad bulb itself could cause all sorts of odd problems. I would still isolate the brake light switch and make sure all the grounds are good.
First things first...check the brake switch, yes by "shorting the terminals" I mean to connect them together electrically with a short piece of wire, screwdriver, or whatever else, But do not let that thing you use to connect them together touch any other metal parts! or you will short the circuit to ground, and melt wires. There are billions of things that can go wrong with electrical systems, and one of the major things is that parts go bad. Another major thing is that wiring connections fail, often due to corrosion. The many examples of fixing light problems by repairing ground connections are all valid...but the symptoms are not the same as what is going on here. The symptoms here point to the brake pressure switch being bad. If you want to go ahead and check out all the wiring for other loose connections, you can. I usually wait until the symptoms indicate that there's a problem in that area.
I just finished resurrecting my late dad's tilting utility trailer. Pulled off the deck and installed a new basic lighting kit. The kit wiring provides a molded multi-circuit wire almost 20 feet long to power all the components directly from the car/trailer connector. The lights' mounting screws are supposed to ground to trailer frame. I sanded the paint off the trailer chassis so the mounting screw nuts and lockwashers The ground wire at the connector is less than 2 feet long, so is attached to the trailer tongue. After I got the lights mounted, and the trailer wiring secured, I wired a tail light converter with trailer connector into the European tow car. I went to test the trailer LH directional light. Nothing. GRRRR. Dang Cheap W*lm*rt trailer lights. I dug out my digital multimeter and set it for 20 Volts DC. I used an alligator clip test lead ( http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Wire-Test-Leads/_/R-NW_784609_0362424365 ) to connect the multimeter black/negative probe to a car chassis ground. Then I started poking around with the positive probe with the car lights on. There was a full 13 volts all over the place from the light mounting screws, and the main trailer chassis, but zero volts on the trailer tongue. Apparently the tongue pivot bolts are too rusty or painted to conduct any electricals. Adding a wire from the tongue to the main chassis across the pivot joint, and all the lights starred working. The voltage drop from the car chassis ground to the main trailer chassis was 0.4 volts with just the tail lights on, which is 2 or 3X too high. It would probably be even higher if the brakes and turn signals were on. I probed my way back checking each screw and joint. The voltage drop seemed to be the wiring kit's wire and connector assembly. I plugged and unplugged the connector a few times trying to scrub the connection clean and reduce the voltage drop. No better. The lights are pretty bright, so I'll leave it for now. The Bottom line is, measuring the voltage drop led me right to the main problem, with no parts swapping or repeated un-necessary cleaning/tightening calisthenics required. ============= If there are any worried about voltage drop tests being non-traditional, check out this page from the 1955 Chevy factory shop manual starter system checking section. http://chevy.oldcarmanualproject.com/shop/1955/55csm06y24.html ============= decent ================ The lower half of this page here is fairly useful. http://www.fluke.com/fluke/uses/com...articlecategories/electrical/diagnosevoltdrop ========== From Delco Remy - Substitute "While energizing the starter to crank the engine " or "with the car running and the headlights and blower motor on" for plumbing an adjustable load carbon pile into the circuit. ============ This is long winded, and DANGER the first 12 minutes shows how to go down the wrong path, that is, what NOT to do.
That's the right way to do it. When it gets fun, is when you are trying to find that last bad ground...you touch the voltmeter test lead to the light socket, and the light goes on. Huh. Eventually you find that where the socket is crimped to the housing, there is internal corrosion....which is fun to fix....
Your turn signals blink slower for one of several reasons, one may be a bad battery the other may be that the generator or alternator is not making enough zot to keep up. if the battery is weak the power is going to keep it charged which is taking away from the rest of the system. As for trouble shooting your wiring there are a lot of back yard options but your bets bet it to buy a multi meter. I just wore out a 7 dollar radio shack digital after about 20 years of constant use. easy to check the switch turn your meter to ohms the symbolis below. Now touch the leads together and see if it reads zero of not there should be a little wheel that you can turn on the meter until it reads zero now you are calibrated. touch both leads to the pins on the switch and have someone depress the brake, it should read zero if the switch is making up if not get a new switch.
...but never use an ohm meter on any circuit that has power applied to it! like the brake light switch...unless you disconnect the car's battery cable first
I would think that removing the leads so that you can get to the pins on the switch would be a given. maybe not, my bad. But you are correct the best way to fry a meter is to try and check resistance under load. I had a guy fresh out of school try that on a relay to some lights ( 240) and after we removed the melted plastic from the palm of his hand I had the opportunity to explain his mistake to him on the ride to the e room.
Assuming that you have brake/turn signal bulbs, and not separate turn signal bulbs in back, your problem is brake switch and/or turn signal switch! If turn signals work back in the back back there, and the tail lights work, ground should be good. If you have hydraulic style brake switch then it might have gotten to where you really have to hit the brakes hard. I have seen this on older vehicles.
When I clipped my 40 Pontiac and added the front disc brakes, the car stopped so good it did not trip the brake light hydraulic switch. I had to go to a manual switch. Gary
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