Bake Lights-non opererable

[Jon Scully]

Hello All,

Just another 'stupid' electricial question--If someone knows where it is a;ready answered-- I will go there, just trying to keep the blazer side growing -

1) Symptom- Brake lights not working.
2)Whats been done: Bulbs, are correct- 1157, look good. Running/turn signals work. Fuse for Brake lights is good. There is power at the switch 'when operated'== But no power at the ass end of the truck....

Now I have looked over my wirring-- It apears to be the stock harness from firewall to rear frame- The problem I am having is 1) It is really cold to poke a test light in the harness (especially a 41 y/o harness) -- It is the BRWON wire for brak lights right? 2) Not sure how to test 'where the break is'......


I am looking to fix this properly-- but NOT buy a new harness.......

Suggestions??? Any would be helpful,

Cold And frustrated (WE average -20 to -40 celcius here in THunder Bay for Janaury /Feb)

Jon

[BIGBLU 72]

man i have the same exact problem! no clue what the problem is?? changed all the flashers etc, checked the man plug?? im at a loss on this one too, i really hope someone has some answers

[Jon Scully]

Thanks-- Misery loves company lol-- I just bought the truck, and need to fix this before I can safety it (in ontario we have to pass a safety inspection prior to registration).


Hope someone can point us in the right direction!

Jon

[bouncytruck]

Is it grounded?

[Jon Scully]

I think so==I am not 100% on this-- but when I put a test light (that is grounded) on the power wire that is comming from chasis harness to the brake harness (brown wire) Should there not be power here (i.e--test light goes on when brake pedal depressed??)

All I mean is that the ground is being replaced by the grounded test light-- at this point in my diagnosics I have: power at fuse, switch, and pedal-- But no power at the chasis harness- that goes to the brake harness.....

Thanks

[Cap'n Hook]

I guess I'd check back at the tail light housing, and make the bolts holding the housing in are grounding the housing good. I had issues with my Jimmy when I first got it, and that was the problem.

I took out the bolts holding the housing in and sanded the surface where the bolt contacts it, and reinstalled everything, and it helped!

[jasons]

The brake lights use the same filament in the bulb and the same wires, green and yellow, as the turn signals. If you have working turn signals the problem is not in the wiring or bulbs. If you have 12 volts coming out of the brake switch when depressing the pedal your problem has to be between the brake light switch and the turn signal switch, most likely the problem is in the turn signal switch.

[Jon Scully]

@Jasons-- So you are saying that I may have a defective flasher (or do you mean the turn signal switch in the sterring column? I had no idea-- I assumed there would be a different 'wire' for the brake lights.....

So-- sorry for the naive question-- But where exactly is 'between the brake light switch and turn signal switch'' is this all under the dash....steering column.

Thanks for the input!!! much appreciated!

[1970 Bowtie]

Originally Posted by Jon Scully

@Jasons-- So you are saying that I may have a defective flasher (or do you mean the turn signal switch in the sterring column? I had no idea-- I assumed there would be a different 'wire' for the brake lights.....

So-- sorry for the naive question-- But where exactly is 'between the brake light switch and turn signal switch'' is this all under the dash....steering column.

Thanks for the input!!! much appreciated!

Yes,it is all under the dash,you have to lay on your back under the dash and you will see the brake light switch.Also do a search on wiring diagrams,there is a lot of threads with good info.

[jasons]

Originally Posted by Jon Scully

@Jasons-- So you are saying that I may have a defective flasher (or do you mean the turn signal switch in the sterring column? I had no idea-- I assumed there would be a different 'wire' for the brake lights.....

So-- sorry for the naive question-- But where exactly is 'between the brake light switch and turn signal switch'' is this all under the dash....steering column.

Thanks for the input!!! much appreciated!

The wire from the brake light switch will go to the harness in the steering column then to the turn signal switch. This is what only allows one brake light to be on when the turn signal is activated.

Use a test light to find the wires coming out of the steering column for the right and left turn signals, the test light will flash with the turn signal activated. Then with the turn signals off both of those wires should be hot when the brake pedal is depressed. You can also use the test light to find the hot wire from the brake light switch going into the column. If you have 12 volts going into the column from the brake light switch, but not coming out you may be able to clean the contacts on the turn signal switch or just replace it to solve your problem.

[Jon Scully]

Thanks Guys--- This is encouraging, as I have not had luck thus far!!!

It is -26celcius here....so It may be the weekend before I get a chance to post my update!

I have yet to pay a mechanic yet since my first car.....sure as hell not going to for a 40y/o truck--that would take all the fun away.

I cannot say enough how great a resource this website is-- great community!!!!!!! One more reason to be a proud K5 owner!

[jasons]

Let us know how it works out when you have a chance to work on it.

[trz1000]

I had the same problem with my truck last week. Turn signals worked but no brake lights. May or may not be the same cause for you but I ended up finding that one of the spade connectors in the brake switch plug had broke and the wire was pulled out of position enough to not make contact with the switch spades. I cut out the plug and installed new spade connectors and problem solved.

An easy way to check if the wiring to the lights is good is to simply put a jumper between the spade connectors in the plug. If the lights go on it's either a bad switch, a maladjusted switch, or you're not getting good contact with both wires. If they don't go on you need to start suspecting bad grounds, the turn signal switch, break in the wires, etc.

Good luck! Working on the brake light switch totally sucks though it's probably easier if you pull out the dash. I don't know as I wasn't smart enough to think of trying that until after this little exercise.

[maynardtruckin]

replace your turn signal switch. I had the same problem and the brake lights go from the brake light switch to the turn signal switch and the turn signal switch is not getting good connection through the brake light parts.

[my90k5]

Had the same prob with my brake lights, replaced the turn signal switch which I got from LMC and all is good now.

[Jon Scully]

Thanks Guys, This site and community is amazing! I plan to get some more diagnostics done this weekend--but will prob oder the part anyway if it is the one I suspect-- not that bad a price:

I had a lok at the LMC catalogue (have not even called NAP --would they have it?)

Here is the page I am looking at:

http://www.lmctruck.com/icatalog/cb/full.aspx?Page=127

So-- Is it part number # 11 that I am after?

If so let me know-

Thanks
Jon

PS_ WIll post pics etc once I gt ahead o the game.....in the meantime- Here is a link to the 'add' that got me to buy the truck:

http://www.carster.com/car-pictures/...-230538734769/

Let me know what you think of my new toy!

[jasons]

That's not it. The part you are after is #26 on this page.
http://www.lmctruck.com/icatalog/cb/full.aspx?Page=155

[maynardtruckin]

Napa has the parts or can order the parts. the part number is ECH DL6194 and it runs about $83 but Checker O'Rielly has the part number s3237 at about $37 and its just as good. Lmc sells sub standard parts.

[Jon Scully]

Hello Again,

Thanks for all the help and advice! Once you guys said that there is wirring components going to the steering column, I traced the wires and found that there was a loose connection--- problem solved!

PS__
Took my eleven year old boy out for his first ride in the k5 today-- He loved it --so did I-- To see his face when he heard the sb rev out and power thru second gear lol

thanks again
jon