Author Topic: Brake lights permanently on!  (Read 2530 times)

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Offline gturner008

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Brake lights permanently on!
« on: Sunday,August 09, 2015, 12:35:19 PM »
Noticed my brake lights were on all the time. Even with keys out of the car. Disconnected battery to get the darn things off!

Should I suspect sticking brake light switch? Guess that switch in the pedal assembly? Easy fix? Or am I looking at a wire that's letting me down? Any advice welcome

Offline BDA

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Re: Brake lights permanently on!
« Reply #1 on: Sunday,August 09, 2015, 01:03:09 PM »
It sounds like the brake switch is stuck. The switch is located on the frame near the battery. You might also have a short on the green/purple wire coming from the brake switch. I think this is the part of the wiring you need to inspect (GP is code for a green wire with a purple tracer). It was taken from the TC (UK) wiring diagram.

Offline gturner008

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Re: Brake lights permanently on!
« Reply #2 on: Sunday,August 09, 2015, 01:49:33 PM »
I'm really showing my poor knowledge here, but you're saying the brake switch is nowhere near the foot pedal? It's in the engine bay? Does it work by pressure in the brake line? Thanks. Gary

Offline BDA

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Re: Brake lights permanently on!
« Reply #3 on: Sunday,August 09, 2015, 02:20:09 PM »
Well, I've already gotten caught by my ignorance of how different the UK and Federal Europas are. On my TC Federal Special, it's near the battery. I suspect it's the same for all TCs, but that's not guaranteed. I've seen the brake switch on the pedal before, but I think that was on an MG or something (way back in the dusty cobwebbed recesses of my mind I seem to remember that a guy who raced MGs would play a trick and adjust his pedal operated brake switch to come on early or late to fool his competitors). I think that was an older method and Lotus used a more modern setup. Take a look there first. It should be pretty easy to see if it's there. There'll be brake lines running to and from it!  :)

On second thought, I'm cooling on the short scenario. I'm thinking it's is most probably the switch.

Offline gturner008

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Re: Brake lights permanently on!
« Reply #4 on: Sunday,August 09, 2015, 03:16:17 PM »
Think you could be right about the MG. it's late here in UK. I'll look tomorrow evening. Part must be cheap. I'll call Paul Matty and get a part. Sounds like a switch. Thanks a lot. Gary

Offline Grumblebuns

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Re: Brake lights permanently on!
« Reply #5 on: Sunday,August 09, 2015, 03:19:42 PM »
Looking at a federal wiring diagram, the brake lights come off the first fuse which is switched. With the ignition switch off the fuse should be dead, thus no power to the brake light. I would check to see if your brake light wiring is connected to the correct fuse connection. Check your ignition switch. With it off there should be no power to the fuse box except for the one supplying the side markers and parking lights.

For an S2 the brake light switch is located outside of the right frame rail just aft of the bulkhead. On a TC it's the opposite side, inside of the frame rail. 

Offline gturner008

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Re: Brake lights permanently on!
« Reply #6 on: Sunday,August 09, 2015, 03:24:25 PM »
Thanks. My brake lights are on all the time. Even when I remove the key, lights still on. Strange.  As you say, even if the switch is stuck, lights should still go out. I'm hopeless at electrics. Process of elimination I think.

Offline BDA

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Re: Brake lights permanently on!
« Reply #7 on: Sunday,August 09, 2015, 04:59:34 PM »
I think the brake lights are independent of the ignition so that wouldn't be strange. I suspect the switch is bad and you just need to replace it. Of course, that opens up the brake system so you'll have to bleed them, but it shouldn't be a big deal. You could probably get a 'generic' switch. They're pretty common.

Good luck and let us know how it goes!

Offline EuropaTC

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Re: Brake lights permanently on!
« Reply #8 on: Sunday,August 09, 2015, 09:58:36 PM »
Thanks. My brake lights are on all the time. Even when I remove the key, lights still on. Strange.  As you say, even if the switch is stuck, lights should still go out. I'm hopeless at electrics. Process of elimination I think.

Hi,

It depends where the feed comes from. If you think about it, your courtesy light comes on when you open the door and that's with no key in the ignition as well. Some circuits will be permanently live (feed for some modern radio's memory is another example).  Without checking the diagram I can't remember if the brake lights are on a permanent circuit but even that doesn't preclude a previous owner getting the fuse box connections mixed up, does it ?  This is a Lotus after all, the car loved by "tinkerers" world wide  !   ;)

The brake switch is hydraulic and on my (UK) TC was also in the engine bay on the passenger side. The image shows the sort of thing you're looking for, there will be two wires going to it. If you disconnect a wire and the lights go out, you've got the answer !  Gently tapping with a Mk1 hammer might loosen it off but personally I'd just replace as they're cheap enough.  They do come in different threads (imperial & metric) so you need to check it's the right part for your brake system.

The mechanical brake pedal switches were fitted to some Elans (I think the Sprints) and would no doubt be cheaper and have been fitted to the Europa but for the pedal arrangement being different.

Brian


Offline buzzer

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Re: Brake lights permanently on!
« Reply #9 on: Monday,August 10, 2015, 05:09:54 AM »
yes it should be located on a brake union just near the battery. Just about all brit cars used pressure switches in the 60's & 70's. goodness knows why, because there is a delay in the lights coming on (pressure required rather than a slight movement of the brake pedal) and from what i can remember always unreliable and sticking on or not working at all.

Dave
Dave,

Other cars. Westfield SEiW. BMW E90 Alpina D3. BMW 325 E30 convertible and Range Rover CSK

Offline jbcollier

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Re: Brake lights permanently on!
« Reply #10 on: Monday,August 10, 2015, 06:19:20 AM »
The brake lights are fed by a green wire.  A green wire is fused ignition power.  Go to the fuse box and pull out all your fuses.  Brake lights still on?

Offline EuropaTC

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Re: Brake lights permanently on!
« Reply #11 on: Monday,August 10, 2015, 08:12:32 AM »
The brake lights are fed by a green wire.  A green wire is fused ignition power.  Go to the fuse box and pull out all your fuses.  Brake lights still on?

If that's the case then it sounds like someone has got the connections wrong at the fuse box. I think there's a permanent live feed on at least one of the fuses so that's the first suspect ?

Offline BDA

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Re: Brake lights permanently on!
« Reply #12 on: Monday,August 10, 2015, 09:18:58 AM »
That's a good guess, Brian! It looks like somebody may have connected the green wire to the brake switch (on the right of the fuse box in the attached diagram) to one of the positions or wires connected to one of the two positions on the left of the fuse box. Or there's a short involving a wire from either of the two wires on the left of the fuse box.

Gary, when you look at the fuse box, IIRC the orientation in the wiring diagram may not match the orientation in the car. You'll need to check that a white wire is feeding the green wire.

Offline Grumblebuns

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Re: Brake lights permanently on!
« Reply #13 on: Monday,August 10, 2015, 11:38:51 AM »
With the ignition OFF, the only circuits with continuous power at the fuse box will be the courtesy light and what ever else a PO has hooked up at that fuse position. For a brake light to be continuously on with the ignition off, a brake light switch will have to be stuck closed, assuming a stock setup and have power from a live source. I would first check to see if there is a green wire attached to the fused position for the courtesy light (purple wire) Other wise basic electrical troubleshooting is in order.


Offline BDA

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Re: Brake lights permanently on!
« Reply #14 on: Wednesday,August 12, 2015, 08:15:53 AM »
Gary,

Is there an update on your brake lights?