Brake Lights Inoperative

[Oldcarhobby]

Greetings all,

My brakes lights, on my '66 BJ8, stopped functioning. My brake switch is located on the pedal (thinking this must be a mechanical switch) with the roller mechanism. I have done the following checks: bulbs are good, I pulled the two wires off the switch and jumped them - no lights came on, cleaned up all wires attached on stop light housings, all grounding wires in boot seem to be solid. I do have voltage to the switch. I thought with voltage to the switch and jumping the wires the lights should illuminate - not happening. I do have a third brake light (mounted on luggage rack) which has been working fine all along. Being this is my first Healey, not sure of next testing steps.

Any ideas or help is greatly appreciated. Many thanks.

 

[RDKeysor]

I've just been through this and eventually found the problem in a wire to the electrical switch box. My complexities include the PO having electrified the reflectors above the brake/tail light fixtures with Halogen 5-watt bulbs. I still have the original hydraulic switch on my BN7's brakes, though years ago I installed an electrical switch that operated off the brake pedal arm and worked very nicely in a Jaguar MK2. In fact, the current owner, who did a lot of upgrades on the Jag, told me he retained that switch. I know I am diverting here, but it is often reported that the electrical switch provides quicker brake light activation than the factory hydraulic switch that triggers the brake lights. The nice thing with that setup is you simply connect to the electrical connection on the original hydraulic brake signal switch for the electric system and, leaving the original wire in place, can reconnect that wire back on the switch if you desire. I know, blah, blah.

 

[John Turney]

Did you install the mechanical brake switch and third brake light? If not, do you still have the hydraulic pressure switch? Perhaps the mechanical switch operates the third brake light and the pressure switch is supposed to operate the regular brake lights.

Fortunately, the late BJ8s have simpler wiring without the 8-way relay on the left front fender.

 

[Keoke]

Might be an inline fuse some where in the mechanical switch's 12V feed.??

 

[GregW]

Check the wire connectors in this area. Left side trunk, green/purple wires at their connectors is my guess.

 

[Oldcarhobby]

greetings, many thanks for all your suggestions , still no brake lights, found a few what looked a few corroded

connections . Thinking of removing my third brake light from the circuit to see if that might be the culprit.

One would think if I have voltage to my switch on the pedal and jump those two wires and still have no lights there

must be a broken or loose connection somewhere in the brake circuit ... correct ?? The hunt continues .

 

[LarryK]

Have you checked the voltage? Not just shorted the wires?

 

[steveg]

Check the bullet connectors at the firewall right near the steering column. The ones going straight down beside the pedal box are the harness going to the rear of the car: brake/turn & running lights, license plate light and fuel pump.

 

[Keoke]

One would think if I have voltage to my switch on the pedal and jump those two wires and still have no lights there


Seems like all this says is that the light is defefetive--?

 

[RDKeysor]

I put a mechanical brake switch that electrically operated the brakes lights on a Jaguar since sold. I also put a third brake light on that car. I have the standard electric/hydraulic brake switch on my Healey and have fitted a third brake light, an inexpensive Chinese bit, that mounts with a single screw that uses the hole in the aluminum trim piece in the back center of the car, a roadster. I have this light on a hinge so that it can be lowered out of the way when either the tonneau or the top is installed, something I rarely do here in north Florida. As mentioned earlier, this car also has illuminated reflectors installed by the previous owner.

 

[madhouse]

I had read elsewhere in this forum that the brake light pressure switch doesn't work well with modern brake fluid. I replaced two, then put in a micro switch just behind the brake pedal. leave the switch in place but jumper the wires to the new micro-switch Its worked for 2 years now.

 

[Bob_Spidell]

I had read elsewhere in this forum that the brake light pressure switch doesn't work well with modern brake fluid...

I can't for the life of me think of a reason this would be the case. The pressure switch is a rubber diaphragm that, when stretched by brake application, makes electrical contact between two terminals (not unlike the terminals under the horn button). The diaphragm could be stiffened or cracked by some chemicals, but DoT3 is a 'modern' fluid--it's specified in some ABS systems because of its anti-foaming properties--but has been around for decades. The switches do degrade over time regardless of which fluids are used (it's a rubber thing).

My '96 Ranger has a potential problem: There is a similar contact switch in the MC that, when activated by brake pressure causes the cruise control to disengage. There have been instances where the rubber 'barrier' in the switch cracked, allowing current to ignite the brake fluid. There was occasion where the resultant fire caused a garage to burn down.