Brake lights have "stopped" working!!

[trim code 76]

My last puzzler.* I recently took my rear taillight pods out, cleaned them extensively and put them back in.* Now my brake lights stopped working.* The bulbs are good and I tried a new brake light switch off the master cylinder.* Checked the wire connections there as well.* No help.* The wires are in excellent shape around the tail light pods and the turn signals and rear lights work, just no brake lights.* WHAT GIVES????? (I hate electrical problems!!!!!!!!!!!!).* Thanks again guys!!!!!

[JohnG]

First I would see if I had any power at the brake light switch. Hopefully you have either a multimeter or test light. One of those two wires to the switch screwed into
the master cylinder assembly should be hot. IF it is then connecting the two wires together should make the lights come on as you have bypassed the switch (I use a drill bit as both are female)

If neither wire is hot then you need to go to your headlight switch as that is where the power comes from (see article I wrote in Technical Resource Library on headlight switches)

If one IS hot then the problem is between the switch and the rear end.

I often ask myself the question when something fails "since it recently worked OK and I just worked in the area, am I the cause of the problem?" meaning that I accidently disconnected the hot lead to the rear taillights somehow...

John

[LuckyJay]

My 60 HT had a blown fuse under the dash near the ignition switch that caused the same problem.

[JohnG]

good point... if he did not disconnect the battery and shorted out a hot lead while working then the fuse would quietly blow. As the power comes from the headlight switch and on the 60 there is a fuse then that fuse has to be checked if he finds no voltage at either of the two leads to the brake light switch on the MC. If he finds voltage then the fuse is off the hook...

The switch, for me , is no fun to get at. With the fuel gauge removed, I can look at the whole thing and maybe get at the fuse with no further dismantling but I am not
sure on this one. But first things first...decide if there is power from the switch.

john

[trim code 76]

no brake lights

THANKS GUYS! I can't believe i forgot about that fuse. (Electrical is my worst area). I will check on SAt. and let you know! Cheers and get them birds out!! Also, anybody on this sight from the northwest? I will be taking the car to the regionals in Spokan WA in 2009. See you there!!!
Greg

[JohnG]

by all means let us know how you make out!

john

Ps The brake light power is not switched... it is always On independently of the key and Ignition Switch. So if one is working in the area, caution is needed, or disconnecting the battery. In other words, with no key in the Ignition Switch, and you step on the brake, the lights will come on.

[byersmtrco]

by all means let us know how you make out!

john

Ps The brake light power is not switched... it is always On independently of the key and Ignition Switch. So if one is working in the area, caution is needed, or disconnecting the battery. In other words, with no key in the Ignition Switch, and you step on the brake, the lights will come on.

What he said !!!!!!! Check those old style "pole" connections.
My brake light switch is 1973-1978 1/2 Harley Davidson FXE
But it does have those dumb connectors like he orig had.

[trim code 76]

still no brake lights!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Ok, sorry not to get back sooner on this, but other things have taken priority.... I just checked both fuses on the light switch and both are good. I cleaned each push in connection for each tail light socket and all are good and clean. On both sides, the outer two red lights come on when the head lights come on. The reverse lights come on when they are suppose to. I have replaced the brake light switch on the master cylinder and that did nothing. My wiring is in excellent shape. I checked the light bulb connections, all good. COMPLETELY STUMPED!!!!!! ANY IDEAS??? Thanks guys!!
Greg

[JohnG]

Cleaning connections is an excellent idea but you still have to get a multimeter and follow the voltage. That the tailights and reverse come on OK is pretty much irrelevant.

1) do you have voltage at the brake light switch? Y/N?

2) If No do you have voltage to the brake light switch from the headlight switch?

3) If Yes do you have voltage at the center contacts of the rear brake lights? (connect the two leads that go to the brake light switch together to perform this test)

But no matter what you have to determine where you do and dont have voltage in the circuit.

john

[LuckyJay]

As I said and has been mentioned before, see if you have voltage at the Stop switch. If not, look for the in-line style fuse near the ignition switch. It may be folded back up against the dash (hiding). It is NOT on the headlight switch. Before you dig too deep, pull the + lead off the battery post as this system is hot all the time. Be careful with the battery connected or learn how to use an ohmmeter when the car battery is disconnected. I was able to get enough length in the fuse holder to move it closer to the underneath side of the dash to replace the fuse more easily. Good Luck.

[trim code 76]

Thanks! I guess I will buy a multitester and check it out. As I said, electrical is by far my worst area, in fact I will have to learn how to use it! I much prefer mechanical and restoration over the gremlins of electrical. Oh well, time to learn. I will keep you informed. Thanks again for the help.

[Guest]

After you are sure you have power to the brake light switch,and you have jumped the power direct to the line that goes back to you brake lights and they don't work then the problem may be in the wiring that goes to the back to the brake lights. Using a Multimerter I would run a seperate wire from the brake light switch wire out side the car hook one end to one of the lines on the multimeter,and then check each light connection of the brake lights to make sure I have connuity at the brake light, if you do then you know that the wire from the brake light switch to the rear is good.I would then check the light bulbs with the multimeter to make sure they are good.

[JohnG]

I got a multimeter in the sale bin at the local autoparts store for $9 recently. They dont last forever but do OK while they work.

You want to find the DC scale for voltage first of all. Then you need to develop a litte confidence with it.

Open the hood and test the voltage across your battery. You should see a reading of somewhere between 12 and 14 volts. Set up the meter so the Red lead goes to + and the Black lead goes to Com on the meter (which goes to - on the battery). If you can get this to work for you (get the 12-14 volt readings) you are off and running!!

With that success, go to the two leads to the brake light switch on the master cylinder. Touch your black lead to the master cylinder for a "ground" (-) and your red lead to the two leads to the switch, one at a time. One of them should should 12 volts or so. If not, you know the problem is at the headlight switch (see earlier posts). If there is voltage then the problem is between there and the rearend.

Keep us posted!! If you are going to have an old car then a multimeter is an important tool, but also easy to use.

John

[trim code 76]

Thanks Guys!!!! Your A Big Help. Will Check This Week And Let You Know. This Sight Is Very Helpful!!!!!! Knew I Bought A Squarebird For More Than Just A Very Cool Car!

[trim code 76]

ok, got the multitester, and I have NO power at either lead going to the brake switch (battery is at 12). So it is either the headlight switch or the in line fuse (?). I have checked my manuals, wiring diagrams and they do not show this fuse (?)(maybe I can't read the diagrams, QUITE POSSIBLE!). So it is around the the ignotion switch? Do you know the color wire I am looking for? I ALWAYS keep the car (all cars) stored with the battery cable off (+). I guess it is possibe I did some work at one time with it on. I will be looking for this in line fuse to see the condition of it. I thought the only in line fuse was for the clock. THANKS GUYS!! Again, this sight is fantastic!! I have other cars and there is no other site like this, then again, there is no other car like the squarebird!! I have a little time left so I will do a little prelim hunting.