only 1 brake light!!!!

[68 special]

Ok, here's the situation.

Replaced front drum brakes with K/H disc brakes. All brake lights on. adjusted master cylinder rod so brake lights are off when pedal is relaxed and replaced stop light switch. NOW, only the drivers side brake light comes on!!!! Ideas???? Checked wiring to switch and grounds at the r/h taillight. Still only 1 side. very puzzling indeed.

Bret

 

[franklinair]

The brake light switch supplies 12V to & thru the turn signal switch to the brake light circuits- it does not differentiate between left or right. The turn signal switch does that. My guess would be a faulty turn signal switch OR a bad connection to the right brake light wire at the harness connection. (This is based on the assumption that the right brake light wiring integrity is OK)

Neil

 

[Ruppstang]

+ 1 Marty

 

[68 special]

I guess standing on my head, I didn't get the wires on the switch completely engaged, because I went in , had a brew, pondered the situation, went back out, stood on my head again and both are working now, who knows. Gotta love the classic cars. My wife said, "I don't know how or why you keep working on something over and over, You must really love that car." I said "keep it up and it will be here longer than you." Good thing she knew I was joking. (sorta). AAAHHHHH, GOOD TIMES.

Bret

 

[admin]

Bret, glad you got it fixed. That is odd that a partially plugged in brake light switch would give you only one side of brake lights. As Neil said that switch is an all or nothing sort of deal. If it happens again the turn signal switch (under the steering wheel) is a good bet as mentioned. If the wires/contacts in that plastic turn signal cam get hot they can partially melt the plastic causing a condition where they sometimes connect and sometimes don't. Causes intermittent turn signals also.

My strangest brake light issue came right after I had my very first Mustang painted in high school. The body guy had patched a small hole in the rear quarter panel with a mig welder. The weld was too close to the rear wiring harness and melted off the insulation, grounding out the circuit. That one took me a while to track down and it was one of my first lessons in "99% of the time it's the last thing you did, no matter how unlikely."

 

[rvrtrash]

I have to agree with the turn signal switch. You've probably had a problem with one side for a while, but just didn't notice. I'd have someone watch the tail lights while you apply the brakes and then wiggle the turn signal lever a little. See if one side drops out.

Steve

 

[aemoo28]

I will share my sign with you.

Hey Rob, remember this? Guess it wasn't such a hot idea to advertise to traffic cops that my car was not street legal without brake lights.

Here Bret, you can use my sign.

 

[aemoo28]

Oh and here's Rob trying to get to that brake light switch under the steering column. What a project. We got to talking and realized after we "switched out the new one from the old one" that we'd actually REinstalled the old relay switch instead. Friends + etoh + hot summer days = goofiness.

 

[68 special]

Love the Satan pics, Amy. I bet Rob had to do the "cat" arch after that, I did.

I thought of the signal switch, but just replaced it awhile back. All the turn signals and taillights work, so I was almost positive it had to be the stop switch. Here's another question for the experts. Would it make a difference if I retained the original "drum" brake pedal versus using a "disc" brake pedal? From what I've read, basically the only diff is leverage to make applying brakes easier.

Bret

 

[franklinair]

From what I've read & heard, you must use a P/B pedal. (Different lenght/folcrum??)

Neil

 

[CougarCJ]

From what I've read & heard, you must use a P/B pedal. (Different lenght/folcrum??)

Neil

Correct, power drum and power disc use a longer brake pedal.

Anyone doing a disc brake conversion can use 1968-69 disc brake pedals from a Cougar or Mustang with the closed 'J' push rod. A 1970 disc brake pedal can be used if the matching 'lollypop' push rod is used.

1967 disc brake pedals will not reach around a 1968 collapsible steering column.