brake lights

[4380r]

Checking out car for a drive tomorrow. all lights work except brake lights. All fuses look good. things to check? I'm looking at a TC wiring diagram and there is a brake switch...where is that located?

[Arizona]

It's a hydraulic switch (as opposed to a mechanical one). Look for it in the brake line just near the oil dip stick.

[4380r]

Found it.

Wires are snug.

Bulbs ok.

Hazard lights don't work either.

All turn signal, reverse, side marker, headlights (hi/lo), dash lights work ok.

[4380r]

Looking at wiring diagrams and the KB, maybe a wire came off the relay. Where physically can I find the relay on a TCS?

Thanks

[4129R]

The brake light switch on the rear chassis below the battery, gets its feed from the green wire from the fuse box. This green wire then also gives power to the reversing light.

When checking the stop lights, do you have the ignition on? The green wires are either live in the 1st or 2nd position when turning the ignition key.

[4380r]

The brake light switch on the rear chassis below the battery, gets its feed from the green wire from the fuse box. This green wire then also gives power to the reversing light.

When checking the stop lights, do you have the ignition on? The green wires are either live in the 1st or 2nd position when turning the ignition key.

Car was idling when I checked. Reverse lights work.

[4129R]

Then check for power at the brake light switch. It should be the green wire, and there should be two green wires going to the one connector.

[4380r]

Then check for power at the brake light switch. It should be the green wire, and there should be two green wires going to the one connector.

Thanks. I see that on the wiring diagram. Looking at the diagram now, some help reasonging through this?

Looks like the green goes from fuse, as you say to the brake switch, then a green goes from the brake switch to the reverse switch, powering it. Since the reverse light works, that suggests juice is at least getting to the brake switch.

Diagram says Green/Purple then goes back up front to the light/signals relay to #5 on the relay, comes out of relay with GR wire at #6 for the LH indicator front and # 7 for  LH inidator and brake rear.

GW wire comes out of relay at # 2 fpr RH indicator front and a GW out of #3 on the relay for RH indicator and brake.

Both rear indicators work. The brake light is not the indicator light, correct? The brake and hazard bulbs are one and the same.

So if, by the rear indicators are working, power is getting back to the rear lights, and the turn signals working means that power is coming out of the relay...so relay probably isn't bad. R and L circuits come out of the relay with different wires, so failure means it has to be something common to both circuits.

So it may be zeroing in on the brake switch itself. Possible to short it out when checking oil?

[4129R]

If the green wiring is live with the ignition on, put a volt meter on the other side of the brake pressure switch and test the voltage when the brake pedal is pushed hard.

If you have voltage, the fault is between the out wire and the rear bulbs. If you get no voltage, the pressure sensor is broken.

[4380r]

If the green wiring is live with the ignition on, put a volt meter on the other side of the brake pressure switch and test the voltage when the brake pedal is pushed hard.

If you have voltage, the fault is between the out wire and the rear bulbs. If you get no voltage, the pressure sensor is broken.

Makes sense. I have the Pertronix ignitor in the distributor. Instructions say to not have the ignition on for more than 20 seconds or so without actually starting the car, that the Pertronix will burn out.

I'd rather not be reaching down there past the headers testing the circuit while the car is running. If I just pull the main ignition wire from the ignition coil will that take the distributor and therefore the Pertronix out of line?

[EuropaS2]

I know nothing about Europa wiring but did you check the bulbs and try cleaning of the connections?

[4380r]

I know nothing about Europa wiring but did you check the bulbs and try cleaning of the connections?

I did, but will recheck tonight.

I know I have juice back to the switch, when I test that as described above I'll know if I need to replace it, or if it's downstream at the relay or the wiring/connections/bulbs.

[4380r]

Checked the brake switch. If the two green wires to one terminal are the 'in' and the single wire terminal is the out, then the switch checked out ok.

Pulled apart the tail lights again and referenced the parts manual. My taillight has only ONE bulb other than the reverse bulb. It is a twin filament bulb. In parts manual all models, S1, S2, TC, TCS have two such bulbs. Taillights and flashers HAVE worked in the past.

If my taillight bulb configuration looked like the manual I'd be defaulting to relay at this point.

Thoughts?

[4129R]

You should only have the one twin filament bulb in a federal spec car, for rear light and the bigger filament bit doubles as a brake light and an indicator light, with the multiple relay doing the magic for brake or indicator flasher.

Other models for the rest of the world have two bulbs, a stop and tail light twin filament bulb, and a separate indicator flasher bulb separated by a horizontal metal bar with amber and red lenses.   

[4380r]

With power confirmed getting through the brake switch, the only thing the flashers and brake lights have in common are the bulbs and the relay, and the turn signals work and visually neither bulb looks burned out, then I must be dealing with the relay?