brake lights don't work??

[rodstored-72]

ok guys,
i know i have asked this before, but i am still not able to find the problem i have no brake lights what so ever. i have all new wiring from m-h from the rear harness to the body harness to the engine harness & now a new dash harness & they still don't work when the lights are turned on the pass. side rear light comes on but no brake lights. when i have the lights turned on the only lights that work are the headlights. i have no blinker or corner lights as well??? i am mainly just trying to get the brake lights to work!!! i think it's a ground, but i have no idea where to look!! i would be very much appreciative if someone could give me some clues as to what could be the problem. i also have replaced all the fuses(since my new harness has the new fuse block as well) all the gauges work & when i turn the blinkers on they show up in the dash but they don't work on the outside??? please help!!!!! i have also replaced all the bulbs!

i could really use some expert advice!!!

with many questions... rodstored-72

[truckdude239]

common place on brake lights where the house meets the body i took a wirewheel to mine cleaned it up and boom everything works

[rodstored-72]

truck dude, i am not sure what you mean??? but the frame & everything underneath is new or has been sanded & painted with por-15. i checked the conn. from the body harness to the rear light harness at the frame & it seems tight plus the light on the pass. side works???

thanks for the input & please!!! keep it coming for i am at a loss on how to fix it. i am sure though what ever it is i will look back & say "well i never would have thought of that!!!"

rodstored-72

[oldcycler]

It might be the turn signal switch. I believe the tail lights, brake lights and turn signal lights all run through this switch. If I'm not mistaken there is also a switch somwhere that senses when the brake pedal is depressed and sends voltage to the stop lamps. I don't remember where this switch is though.

[67_C-30]

The turn signal switch in the column was the problem with the brake lights on my '67 C-30.

[72LoBurb]

Originally Posted by truckdude239

common place on brake lights where the house meets the body i took a wirewheel to mine cleaned it up and boom everything works

I believe what truckdude means is the taillight housing isn't grounding to the body. If you use a wirewheel to remove some paint behind the housing , the housing will ground to the body better.

[GREASEMONKEY72]

and to add to everything check your bulb grounds and make sure they have full contact and also make sure that the bulbs arent burnt to but good luck and i hope you fix it asap

-steven

[rodstored-72]

old cycler,
do you mean the switch at the fuse panel or the actual arm in the column?? i will replace the switch at the fuse if so??. if it's the arm then i will need some guidance. (thanks!)

67c30,
i will try that.. i am not sure how to do it. if i can get some guidance then i will do it. (thanks!)

72loburb,
i will "scuff" it up tonight when i get home from work.. thanks!

greasemonkey72,
when i scuff up the housing tonight i will check for that as well, i am don't remember where the ground wire is for the lights??? will i see it when i take the housing off??

thanks for all the great info.!! hopefully i can get these items checked or fixed & get'er back on the road!!!

anymore suggestions????

thanks!!.... rodstored-72

[oldcycler]

My first comment was to check the turn signal switch - like 67 C30 a bad turn signal switch made my brake lights not work - you will have to remove the steering wheel to replace it.

Secondary was to check the brake switch. It has been many years since I looked at this so I don't remember where to find it - it is not a fuse.

Your most likely problem is a bad ground - like 72loburb and greasemonkey72 said.

There is no ground wire. The ground connection is made from the lamp housing to the body of the truck and from the truck body to the frame. Your battery is grounded to the frame so that completes the connection. If you have all new paint you might not have a connection between the lamp housing and the body and/or no connection between the body and the frame.

I had a previous truck that was a little rusty with grounding problems that I could not solve by sanding and scuffing. I ended up running a ground wire from the lamp housing directly to the frame - I drilled and tapped a small hole in the frame to connect the ground wire to the frame and just used one of the housing mounting screws to connect the other end of the ground wire to the housing.

[rodstored-72]

oldcycler,
thanks again! i am thinking that it is grounding as well. i think now that you mention it i remember a wire from the housing. i will check tonight. does anyone know what the locations are for the "factory" ground straps??? i know there is a faq on it & i printed it out, but to be honest when i read it through i really still didn't understand the locations. i have straps at the engine (originals). thanks again for your help!!!

rodstored-72

[rodstored-72]

ok guys,
well i tried to do some stuff for the lights last night. i checked the brake light bulbs & i did have a bad one. so i thought great i will repalce this & the universe will be right again.... wrong!!! i put a new bulb in the socket & imedaitly it came on & stayed on untill i disconnected the batt.!! so now i am really at a loss!! i don't have a clue as to why the light would stay on even when the key was not on!!! i assume there is a lead wire that for some reason is staying on??
so i am trying to figure out why the light would stay on!!!
if it is a grnd. would the bulb stay on??? please help!!!
i am just needing to get this fixed & then i can begin to drive this 5 yr project again!!!

thanks!!!

[67chevy2wd]

There must be a short somewhere in the brake/taillight circuit. I think it would be helpful for the people trying to help you if you tell us what lights are on when you:

Pull the headlight switch to the first detent (park lights)
Pull the headlight switch to the second detent (head lights)
Step on the brake pedal With the headlights on and off
Use the turnsignals with the headlights on and off and brakes on and off

This might be a little over the top but I am confused as to what lights work and which ones don't.

[rodstored-72]

67chevy2wd,
the only lights that work are the headlights & the pass. rear light when you use either of the detents at the light switch. when all lights are off nothing comes on (except the driv. rear brake light which stays on the whole time even with the keys out). the brake pedal seems to have no effect on any of the lights. all the wiring through out the truck is new (from m-h)when you turn the blinker on the dash light works but not any of the outside lights. at this point i am just trying to get the brake lights to work so i can get through inspection & be able to drive during the day. i am not a elec. person so i am sure my questions seem to be silly... but i am willing to try things if given good instructions.

any help would be greatly appreciated.

thanks!!!
rodstored-72

[rodstored-72]

anymore suggestions????

[67chevy2wd]

It sounds like there is more than one problem, Is the harness that goes from the rear crossmember to the tailights new? Are you sure the one light that stays on is a brake light and not a taillight? They only I know of to be sure is pull the bulb out with all the lights off and see with conector has power should be two or three I can't remember. When you find which one has power find out what color the wire is and that will tell you wether it is brakes or taillights, I don't remember the colors off the top of my head. I would use a digital mulitmeter if you have one if not a testlight will work. Either way if it is the brake or taillights the problem almost has to be in the harness from the rear crossmember to the taillight buckets becuase you tailights come back in one wire and so do the brakelights then somewhere after the rear crossmeber they both split into two wires one to the left and one to the right. So I would think if the problem was more towards the front both lights would be on unless something is unhooked on the other side. Anyways after you find out which wire has the constand power go to the rear crossmember and unplug it there and see if any of the four wires have power there if not then that is good. make sure you have a good ground for you test light or DMM. I am definetly no expert on electrical stuff but that is were I would start and if I am wrong someone else please chip in.

[rodstored-72]

67chevy2wd,
thanks for all the help & time on helping me. i will try all the above things. i too am not good at elect (as i know you can tell). i will see if i can get a buddy who does know elec to come over & help me, he has the tools that you mentioned. i just get soo mad because i buy all this stuff new & i think that i put it back the way it was & then the stuff that worked before i messed with it now doesn't work!. i didn't think that replacing a "clump" of wires would be such an ordeal!!!!

thanks again!

rodstored-72

[CochinoFilipino]

I had a very similiar problem on one of my past cars (don't remember which one). The two wires going to one of the rear tail lamps were crossed. It made the whole system act goofy, kinda like your describing. And on an old Mustang, the bulb was not in properly and that caused weird problems too.

[69TowRig]

I don't have many new suggestions:

1. Get and use a multimeter to check for voltage along the way.
2. Like suggested above, there are a few spots that all the voltage must get through for the lights to work. 1 is the light switch itself, the other biggie is the turn signal switch.
3. Unplug and re-plug in the dash connector. Part of the signal harness runs through that too.
4. If you do not have the wiring diagrams, get them. Somewhere online here someone posted them up.

Good luck with it. When I bought my Blazer the only circuit that worked right was the starting/running circuit (thank God that worked). I spent nearly 2 months worth of evenings re-wiring and debugging the electricals in the truck. Now everything works. It sounds like your problems cropped up more or less all at once so I think there is one thing in the chain that is failing.

[kwmech]

Check this--- The power for the brake lamps comes from the fuse box to the stop lamp switch thru the orange wire, when you step on the brake power is put into the white wire. The white wire goes thru the harness into the connector at the turn signal harness. If the turn switch is neutral, then power will then go out thru the yellow AND green wire---(yellow being left turn and brake and green being right turn and brake). Does that help?

[67chevy2wd]

I have the wireing diagrams but they are a little hard to understand, It would be nice if there was a schematic that shows all the switches drawn out, what wires are connected when the switch is in a certian position. Like the blinker switch and head light switch. I didnt' even see the blinker swith on here just the connector.