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DPM issue - changing the brake light switch - Ride/Handling/Suspension/Brakes/Wheels/Tyres - The Lotus Forums Jump to content
NathR

DPM issue - changing the brake light switch

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Over the past year my cars developed an occasional DPM fault as previously discussed on here...

 

 

 

 

Recently it got to the stage where it was happening on every drive. Thanks to the forum and the above threads I traced it down to the brake light switch. I removed it (without unplugging), pulled the plunger fully in/out then re-fitted it and set it so the brake lights function as expected. For the following two weeks of driving the car everyday (15 mile round trip to work) I didn't have a single issue. 😀 I put this down to a lack of use thing, possibly extending the switch beyond it's normal working range may have cleaned some contacts or something - I have exactly the same problem with the hazard warning switch due to lack of use.

Last week the car was in for the 4 year service so I mentioned this and 'self diagnosed' the problem as my dealer wasn't aware of it. Apparently it had recorded a fault code relating to the brake light switch (the MIL light has never come on so not sure if this is true), I was quoted a frankly ridiculous price for the labour to change the switch so opted to just buy the part and fit it myself, which was fine. Then on collecting the car the previous day I was told actually I can't fit the switch as it has to be programmed in by the dealer, does anyone know if there's any truth in this? Given the simplicity of how a brake light switch works I'm surprised by this. 🤨

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The switch is adjustable, so you need to make sure the adjustment is correct for the position of the pedal.

Lotus have access to a lot of stuff with "Tech Centre", including being able to calibrate sensors.  I recently had a similar issue, but the brake sensor wasn't the cause, it was actually caused by the steering wheel position sensor. Lotus Silverstone expertly diagnosed and fixed it in about an hour.

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It is like 5 or 6 clics out of the switch, I had the same issue, actually bought a new one which would not work fine, so I just changed the setup of the old one .. 

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2 hours ago, NathR said:

Then on collecting the car the previous day I was told actually I can't fit the switch as it has to be programmed in by the dealer, does anyone know if there's any truth in this? Given the simplicity of how a brake light switch works I'm surprised by this. 🤨

Hi Nathan.

The brake light switch is a two-stage affair, and it should be setup using TechCentre, otherwise you may experience the issue you are experiencing.  You might get lucky and it works fine, you might not.

Dave

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I had this exact problem and was paranoid about number of clicks etc but read on another forum to just pull the plunger out all the way and when you fit it into its bracket press the brake pedal in (so it ain’t touching plunger) once it’s in the bracket release brake pedal and let the plunger set itself. I followed that method and it’s been fine for well over a year. 

I find lotus take the absolute pi$$ with stuff like this. Same as with price of spare parts. 

Its a shame tech centre isn’t available like vagcom is

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As I said, you might get lucky, I've seen it work, and I've seen it not work.  Nothing to do with taking anything, it's a two stage switch, which must trigger the ECU before the lights.

VAGCOM is an aftermarket developed tool.  TechCentre is a manufacturer tool.  Although only for about two weeks, as it has been replaced by Lotus.  Service centres have to pay quite alot of money to Lotus for the diagnostic tools.

Dave

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I just meant it’s a shame the end user can’t do the things you can on tech centre. Vagcom is about £150 I think. I’d pay that for an aftermarket tech centre for my lotus 

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I just looked in service manual and there is a section on things you need to do in Tech Centre. Maybe I was just lucky. I don’t see that you can lose anything by trying it yourself first though. Worst case scenario you lose traction control 

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5 hours ago, GFWilliams said:

I recently had a similar issue, but the brake sensor wasn't the cause, it was actually caused by the steering wheel position sensor.

Exactly the same for my car

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Thanks all for the advice, appreciated.

Pretty sure my problem is the brake switch and not the steering sensor given that I seemed to cure it by pressing the switch in further than it would usually operate a few times.

I can't see that the 'setting up' of the switch requires anything other than adjusting the plunger so the lights come on with slight pressure to the pedal (as any other brake light switch). However if unplugging it and plugging in a new one potentially upsets the ECU by the sound of it I think I'll leave it as is, the cars now off the road for winter anyhow. If it persists in spring it sounds like a dealer job to swap.

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