Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: 4380r on Saturday,May 31, 2014, 04:38:41 PM
-
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?
-
It's a hydraulic switch (as opposed to a mechanical one). Look for it in the brake line just near the oil dip stick.
-
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.
-
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
-
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.
-
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.
-
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.
-
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?
-
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.
-
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?
-
I know nothing about Europa wiring but did you check the bulbs and try cleaning of the connections?
-
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.
-
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?
-
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.
-
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?
-
Check for power on the Green/Purple wire on terminal 5 on that relay, when the brakes are pushed. That is the trigger in.
This in turn should trigger the relay to give power to both Green and Red, and Green and White wires, terminals 3 and 7 on that relay.
-
I'll give it a try.
Although where the relay is located I can't tell which terminal is which. And will have to put some thought into how the brake will be depressed while I'm laying under there with my mulimeter. :welder:
-
You should be almost on top of the brake pedal when you are upside down under the steering column looking up at the relay.
Beware, it is not and easy position to get out of, and removing the steering wheel makes it a whole lot easier.
-
If I am laying on my back under the dash, head against the firewall, looking up at the relay (the ends of which peak out from behind the steering wheel bracket, the middle terminals look very hard to access with relay in place), what is the orientation of the terminals?
Wiring diagram indicates 1 and 5 are on the extreme left, 4 and 8 the extreme right.
Laying there I'm looking up at the relay and see the metal housing. Is that the same 'view' as on the wiring diagram, or is the diagram looking at the relay from the other side?
Thanks
-
You will have to trace them through the colours:-
1 is green/brown 5 is green/purple
2 is green/white 6 is green/red
3 is green/white 7 is green/red
4 is green/white 8 is green/red
You need to find if 3 and 7 are active as those go to the red RH and rear LH brake light, respectively.
-
You will have to trace them through the colours:-
1 is green/brown 5 is green/purple
2 is green/white 6 is green/red
3 is green/white 7 is green/red
4 is green/white 8 is green/red
You need to find if 3 and 7 are active as those go to the red RH and rear LH brake light, respectively.
I do see that in the wiring diagram bug, ahh, there is the conundrum, I am partially color blind, so I was hoping to match the orientation of the terminals on the actual relay with those in the diagram.
And since I know that power is leaving the switch, I'd probably test 3 and 7 first. If the juice is going through the relay, but nothing lights, and the bulbs are ok (as evidenced by functioning of turn signals) then I know that there is a break in each of the lines heading back to each tail light, as they are independent of each other. I think it's a long shot that the only two wires a mouse chewed through would be those two lines.
-
Does this help?
-
Does this help?
That's the ticket, thanks! You could be doing something else with your evening, thanks for your help!
Come to think of it, I could be doing something more constructive at work.
-
(http://www.lotuseuropa.org/gallery/albums/album13/Brake_Turnsignal_detail.jpg)
(http://www.lotuseuropa.org/gallery/albums/album13/Steering_column_detail.jpg)
-
Thanks, Joe. I've been studying that very diagram from the KB.
-
Must be above my pay grade.
Issue: Hazards and brake lights do not work.
Tail lights and turn signals work. Conclusion #1: both filaments in both bulbs work.
Visual inspection of fuse looks good. Reverse lights work off same fuse and they are fine.
Confirmed power to and through the switch when pedal depressed.
Confirmed power gets to #5 on the relay.
Replaced original 40 year old relay with brand new one. Double checked all connections and connectors.
Power for taillights and turn signals are getting to the back of the car.
The hazard and brake lights worked until recently.
Only things hazard and brake lights have in common seem to be bulbs and relay. Both check out.
So, power gets to/through switch, to relay, bulbs work, replaced relay.
New relay no good?
Acknowledge DCO (Dreaded Current Owner) might not have installed new relay correctly. But I don't think so. It is pretty straightforward.
Hazards and brakes still don't work.
What am I missing?
-
Is there any power at 3 & 7 terminals on the relay when the brake switch is activated/shorted out?
-
Is there any power at 3 & 7 terminals on the relay when the brake switch is activated/shorted out?
I do need to check my assumption that the brand new relay would be functioning. If power is going into the relay, and it is, but not coming out where it should, then the new relay would be at fault. Maybe there is a short in the wiring that is shorting out the contacts in the relay...on the OEM and the new.
-
Until you sort out what is happening to all the wires going in and out of those 8 connections, I don't think you will trace the problem.
-
I have had some experience with this area, even making my own DB10 Relay substitute, described in Lotus Europa Central.
The brake, hazard and indicator functions share common wiring from the relay to the bulb, so if the indicators are working there's little point in trying to trace a problem there.
Try this - test the brake lights with the Hazard Switch in both the On and Off positions. I think that if the switch is On, but you have a faulty hazard flasher unit, you will get the symptoms you describe. Worth a shot, anyway.
-
I have had some experience with this area, even making my own DB10 Relay substitute, described in Lotus Europa Central.
The brake, hazard and indicator functions share common wiring from the relay to the bulb, so if the indicators are working there's little point in trying to trace a problem there.
Try this - test the brake lights with the Hazard Switch in both the On and Off positions. I think that if the switch is On, but you have a faulty hazard flasher unit, you will get the symptoms you describe. Worth a shot, anyway.
:I-agree:
-
Gone Quiet now. It'd be nice to know if the problem is resolved, and what was the solution.
-
I'm having the same problem here as of just last week with my 73 TCS. Brakes lights stopped illuminating, however rear hazards, rear turn signals, and reverse lights function as normal. It's simply not detecting the brake pedal push. Fuse box fuses are OK. Traced it to either the brake switch by the oil dipstick, or the relay under the steering column. My money is on the brake switch (which has a mechanical component, yes?), because I think it may have been damaged when I had to absolutely smash the brake pedal into the floor to stop the car when some air got into the brake lines. Perhaps pushing the brake that hard that quickly (i.e. increasing brake fluid pressure too fast) broke the switch?
-
You can use a test light to see if the brake switch is completing the circuit. If it is, then it might be the relay. You can test that in a similar way.
Good luck! Let us know what you find out.
-
You can use a test light to see if the brake switch is completing the circuit. If it is, then it might be the relay. You can test that in a similar way.
Last night during my initial inspection I depressed the brake with a piece of lumber and used a multimeter to see if any juice was traveling from post 1 to post 2 on the brake switch. The reading was 0.0. I did NOT yet test to see if any juice was even arriving to post 1 of the brake switch as delivered from the relay (which I'll do tonight).
-
Do yourself a favour and get a 12v test lamp like this:
http://www.benzworld.org/forums/attachments/w163-m-class/581802d1380320782-ml270-cdi-reversing-lights-not-working-test-light.jpg
Test lights put a light load on the circuit and are a much better indication of the quality and quantity of the voltage present. Digital multimeters can often sense a full 12v on the circuits with corroded connections and frayed wires, easily confusing newcomers to electrical troubleshooting.
PS: fused, switched power goes to the brake light switch. Hydraulic pressure closes the contacts and then the power goes to the brake/signal control unit.
-
Check your ground wires also!
-
Traced it to the brake switch. Using the ohmmeter function of my multimeter, I disconnected all the wires from the brake switch and depressed the brake pedal. The circuit didn't complete, hence faulty brake switch. How might one of these go bad? :confused:
-
I had an oil pressure switch go bad which caused it to leak quite a lot of oil. I don't know what they look like inside. If there is a diaphragm, it could have enough of a leak so that it it would not activate the switch but be contained so you didn't lose pressure. Just a guess. After you get your new switch, try cracking it open to see if you can find out why it didn't work. It'd be interesting to find out what happened.
-
I've never had one fail internally either but like all mechanical things no doubt they do go bust. I've had one corrode at the contact tab which meant a new one, but otherwise they've been reliable. Does shorting the switch out put the lights on ? I guess that's the 100% confirmation for a duff switch. A pain to replace if it is the switch, but on the good side your car gets new brake fluid ;)
Brian
-
Brake lights fixed! Swapped the brake switch with a new one, bled the system and refilled. Ta-da! But of course, it's rarely THAT simple...discovered the bleeder screw for the right drum brake was snapped off. Spent nearly 5 hours extracting it before I could even start bleeding the lines. But good now!
-
Glad you got it fixed! :beerchug: