Can’t get brake lights to work (new wiring)

[busmania]

I purchase all new Rhode Island wiring for my 40. Everything has been installed and everything works except the brake lights. The tail lights and blinkers work, but nothing happens when I hit the brake.

I assumed that if I touched the two wires at the switch together the lights would light up. Am I wrong about that?

Any advice or what/where to check?

Thanks y’all.

[alanwoodieman]

yes, short out the two wires on the brake light switch if that makes the lights come on then the switch is at fault. did you install a low pressure bl switch?

[busmania]

I installed the stock style switch with two prongs

Touching the two wires together does not make the lights come on. I feel like there’s no power going to the switch. If my light switch is hooked up wrong, is it possible for everything to work but the brake lights? Everything working but the brake lights makes me think it’s wired correctly. I’m confident all of the wires are in the correct places (except for maybe the light switch cause I kind of just played around with the placement of those four wires until it worked). I’m also using an aftermarket light switch but it has 4 prongs like the original.

[Mart]

Well, you need something that will tell you what is live and what is not live. You need to know, not feel there is no power to the switch.

Also guessing which wires go where is problematic. Wiring diagrams should exist for all your components. Get a multimeter or a test lamp and probe and treat each circuit as a separate entity. Check for live at each stage along the circuit starting at the battery or whatever live feed is used and follow the circuit all the way along.

You just need to be methodical.

We can't say why it isn't working but you ought to be able to trace it through.

Mart.

[deuce lover]

Contact Rhode Island wiring and see what they say.

[Ggmac]

Sponsored Links (Register now to hide all advertisements)

When installing a turn signal, make sure the flasher is correct for the type of bulbs and prongs on the flasher . The reason I mentioned the flashers is that most times the brake power goes through the flasher set up . Double check the connections and make sure you dont need Two bulbs in the tailights assembly. Some tailight wiring ( european ) have a separate bulb . Sorry no coffee yet , hope this makes sense .

[slowforty]

Run a jumper wire with power to the wire going to the brake lights. Check to see if they work. Put the jumper wire on one side of the brake switch, connect the wire going the brake switch. Step on the brake,check to see if they work.

[corvette8n]

Get yourself one of these, I keep it in the trunk of my ‘41. About 20 years ago I bought 10 of these at a dollar store in Ft. Worth, gave them all away over the years. Btw the brake light switch was bad on my 41.

[pistonbroke]

Your turn signal switch is the culprit. You should have power from the brake light switch to your turn switch then it should go out to the tail lights. Are you sure about your turn switch wiring, do your front turns work ? I help a guy who got the front and rear turn wires flipped and when he stepped on the brake the front turns lit up. I can't tell what is hooked up wrong but it will be between the turn and stop light switch . Tim

[busmania]

Thanks y’all. I have a test light and volt ohm meter. Every other light works as it should. I’ll start testing stuff at the turn switch and see where the power gets lost.

This is the first electrical work I’ve really done in 30 years of wrenching so it’s all new to me.I’ve diagnosed and fixed all other electrical issues as they came up so I should be able to figure this out too. Thanks for the help.

[pistonbroke]

That power from the brake switch is only when the brakes are applied. Just saying as some might misunderstand me on that. Tim

[TJ]

From the turn switch there should be a constant hot wire to the brake switch.

[busmania]

Thanks tj. That helps. I’m going to look at it here in a bit and I’m suspecting turn signal switch.

[Mart]

Originally Posted by TJ

From the turn switch there should be a constant hot wire to the brake switch.

No.

There is a constant live feed to the brake switch. This feeds into the turn switch when the brakes are applied.

[jplutz]

As tj states, 1 wire to the brake light is hot, the other goes to ground. Make sure that the ground wire goes to a good chassis or body ground. Bad grounds are often the most common electrical problem on old cars. Good luck, JPL

[pistonbroke]

TJ, Not to be rude but having wired many cars and trucks over the years I have to disagree. The brake light power goes to the brake light switch and on to turn signal switch where it may or may not go to both tail lights depending on the position of the turn switch. There is power to the tur switch but it is for the turn signal function only. That's why your brake lights work anytime you apply the brakes but your turns only work when the key or ignition switch in this case is on. Again no disrespect , Tim

[pistonbroke]

I'm sorry guys, but I just installed the same my new harness from the same supplier so I have to disagree. Tim

[busmania]

Update. Maybe

I have power going into turn switch. Per the switch diagram, the wire going from switch to brake light switch is gray/black. The gray/black terminal that goes to the brake switch has no voltage when I check with a meter. should it read 12v constantly?

Second, I took a jumper wire from hot to black/gray wire at switch. I then jumped the second wire for the switch (green) but still no brake lights.

I’m thinking turn switch is faulty? But don’t want to say 100% because I still have not gotten the brake lights to work jumping the two wires.

Next I’ll make a ground for each tail light but I’m doubting that since the other lights work fine.

Edit: rears now have their own dedicated grounds and still no dice.

[busmania]

I really hate it when a problem fixes itself without knowing what caused it.

Anyway, I called Rhode Island wiring. He walked me through testing from the turn switch app the way to the brake light switch. After everything continuity tested out as it should, we moved to the brake switch. As I tested the continuity there…it all worked, including the brake lights!

I confirmed with him that the way I was testing (bypassing the brake light switch by connecting the two wires ) was in line and ok and so therefore, I have no idea what fixed it. Maybe somewhere along the way a wire has become disconnected. My ONLY complaint on this wiring is the connections come apart easily.

Otherwise…GO BUY A RHODE ISLAND WIRING SET! the wiring is top notch, instructions superb for a newbie like me and the customer service is great! This was the 4th time I called and they helped me.

Thanks everyone…onto my first test drive now!

[Steve in Denver]

I know the surpasses logic, but replace the brake light swithch on the master. I had the same problem and that was the solution. Can't tell you why, but that solved my problem.