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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17705
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
Yes, it would appear to be CJB Fuse 13. If your reversing lights are working than the supply to the fuse should be OK (since the reversing lights are fused by CJB Fuse 14 which is powered by the same ignition feed as F13).

There are two switches on the brake pedal, both of which have separate feeds to the ECM, and one of which also feeds the brake lights. It is however really unclear what the two feeds do (and why there are two), although one of them without doubt is there to detect that the brake pedal is pressed and disable the throttle input if both throttle and brake are pressed (an annoying feature if you need to dry your brakes, but probably a good idea since you will be able to stop even if a throttle malfunction results in the throttle failing wide open).
Post #1036477 4th Jun 2024 2:46pm
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BrickBox



Member Since: 05 Oct 2021
Location: Wales
Posts: 923
Wales 2008 Defender 110 Puma 2.4 USW Zermatt Silver
Your wealth of knowledge is much appreciated Bow down

Thank you. I shall look at the brake switch tonight. 2008 2.4 110 Utility Station Wagon XS.
Post #1036484 4th Jun 2024 4:01pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17705
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
Don't rule out the possibility that both brake light bulbs have failed. It is not unknown for people to think that since neither light is working it must be a single fault elsewhere affecting both lights, but it is quite possible for both bulbs to fail at about the same time.

After all, the original bulbs came from the same manufacturing batch and have been switched on and off the same number of times and illuminated for the same duration, so it is actually highly likely that they will fail at around the same time. It probably gets less likely as the vehicle gets older since the likelihood that bulbs have been replaced differentially is greater.

My policy is always start with the easy checks and work towards the more difficult ones.
Post #1036486 4th Jun 2024 4:23pm
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BrickBox



Member Since: 05 Oct 2021
Location: Wales
Posts: 923
Wales 2008 Defender 110 Puma 2.4 USW Zermatt Silver
I’ve already swapped bulbs and complete tail lights to completely rule that area out as an issue.

Same result with my old (still fairly new) tail lights. 2008 2.4 110 Utility Station Wagon XS.
Post #1036487 4th Jun 2024 4:43pm
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BrickBox



Member Since: 05 Oct 2021
Location: Wales
Posts: 923
Wales 2008 Defender 110 Puma 2.4 USW Zermatt Silver
Just to update this. It was a cheap rear tail light bulb holder causing the issue..! The pins in the bulb holder were touching the earth. Swapped out for genuine bulb holders and a new fuse, revs no longer holding..!


Unbelievable how different things are connected Embarassed

Thank you so much BlackWolf. Your theory is now tried and tested with positive results..! 2008 2.4 110 Utility Station Wagon XS.
Post #1036575 5th Jun 2024 3:00pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20722
United Kingdom 
blackwolf wrote:
My policy is always start with the easy checks and work towards the more difficult ones.

100% Agree, there is often the most silly thing that is at fault usually often a very basic or low value item, if not careful can be found after buying an expensive part. WeWillWin🇬🇧🇺🇸
⛽️🛢️⚙️🧰💪
Post #1036592 5th Jun 2024 6:05pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17705
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
BrickBox wrote:
Just to update this. It was a cheap rear tail light bulb holder causing the issue..! The pins in the bulb holder were touching the earth. Swapped out for genuine bulb holders and a new fuse, revs no longer holding..!


Unbelievable how different things are connected Embarassed

Thank you so much BlackWolf. Your theory is now tried and tested with positive results..!


Excellent! It's one of those strange Puma things that sound unbelievable, glad it worked. Very Happy
Post #1036594 5th Jun 2024 6:18pm
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hank



Member Since: 12 Sep 2016
Location: South Wales
Posts: 2322
Wales 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
On a different but related note, do you think the low resistance associated with LED brake lights could result in the same rev hang issue? > 110 XS Double Cab
Post #1036597 5th Jun 2024 7:50pm
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BrickBox



Member Since: 05 Oct 2021
Location: Wales
Posts: 923
Wales 2008 Defender 110 Puma 2.4 USW Zermatt Silver
I certainly wouldn’t rule it out, if you are having issues. Possibly not enough voltage going through the circuit? 2008 2.4 110 Utility Station Wagon XS.
Post #1036599 5th Jun 2024 8:09pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17705
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
I have LED bulbs in all rear lights except the indicators and it doesn't cause any problems.
Post #1036600 5th Jun 2024 8:16pm
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hank



Member Since: 12 Sep 2016
Location: South Wales
Posts: 2322
Wales 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
I've long suspected that my revs were hanging but having bled the clutch a number of times, changed the clutch switch and 'jumped' the clutch switch pins I figured I was being oversensitive.

Makes you wonder though. Perhaps I'll fit some incandescent bulbs and give it a drive

That said I suppose the variable resistance relay does the same job. Perhaps try tweaking the resistance up slightly and see what happens > 110 XS Double Cab
Post #1036601 5th Jun 2024 8:18pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 17705
United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
No, the relay only affects the indicators, the ECM is only affected by the brake lights.
Post #1036613 5th Jun 2024 10:33pm
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jst



Member Since: 14 Jan 2008
Location: Taunton
Posts: 8208
 2011 Defender 110 Puma 2.4 USW Stornoway Grey
hank wrote:
On a different but related note, do you think the low resistance associated with LED brake lights could result in the same rev hang issue?


No.

Fitted led brake bulbs when I gotnher 106k aho. No rev hang Cheers

James
110 2010 XS Utility
130 2011 M57 bespoke Camper
90 2010 Hardtop
90 M57 1988 Hardtop
Post #1036615 5th Jun 2024 10:40pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20722
United Kingdom 
A failing Clutch switch is another factor that can cause this, and it can happen out of the blue then go away, and then come back or happen a lot causing permanent Rev hang.

If it goes away if you bridge the plug, then you know that it’s at fault right away or you can test it.
You can’t just unplug it on a Puma though, it needs an active working clutch switch or a permanently closed circuit.

Lots of things get repeated like what I’ve mentioned but it can be useful to those who aren’t aware.

Blackwolf - That’s interesting info regarding the two brake pedal switches.
I wonder if they engage at the exact same point of pedal travel, or if they possibly engage at a slightly different pedal depression. Idea
Or possibly LR simply wanted two feeds to two different locations, and decided on two switches to do so rather than sharing a single switch.
Which makes me wonder if the reason is to detect a different level of pedal depression, a response or reading showing the different between light braking and heavier braking.
I know for the brake lights it doesn’t take hardly any travel for the pedal for brake lights to be turned on.
One of the reasons I like LED brake lights is the illuminate faster, and that split second if that helps, also more reliable and brighter and vivid.
But as usual all personal choices we all have, that’s what I love about LR’s is the face that they can match owner taste. WeWillWin🇬🇧🇺🇸
⛽️🛢️⚙️🧰💪
Post #1036617 5th Jun 2024 10:47pm
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hank



Member Since: 12 Sep 2016
Location: South Wales
Posts: 2322
Wales 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
The plunger on one of the switches is adjustable on a ratchet type mechanism. I think the idea being they are supposed to be set up to trigger at the same time. > 110 XS Double Cab
Post #1036627 6th Jun 2024 7:43am
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