LR3 Failed Transmission Fixed With A Light Bulb.

Started by Matt H, May 13, 2020, 12:52 PM

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Matt H

Recently I picked up a poorly Land Rover LR3 with a failed transmission.  I've owned one previously and my wife currently drives an LR4. I have shied away from modern model Land Rover project vehicles of late as they can be hard to work on. But the price was right and I felt like playing with something newer for a change.
The LR3 was locked into park, unable to shift out park and just about every single warning light that worked was illuminated.

There is a neat trick to overcome the shift lock solenoid on the 3 that is way easier than on previous models where the centre console needs to be dismantled. All you do is remove a rubber coin tray and reach inside. So, after having got it mobile and verifying the transmission does in fact have the ability to physically move the vehicle I looked for other possible causes.

One of the strangest things to get your head around with newer vehicles is that the trouble codes are not the be all and end all of fault diagnoses. A fault code is just the pre programmed response to a set of circumstances. Most codes are designed to interpret hard mechanical faults and electrical faults can confuse it. But it's not always very accurate. The more systems you have monitored, the more codes you have, the more warning lights you have the less likely it is any of them is the cause. A lot of time and money can be wasted following these phantom trouble codes blindly.

Anyway, the rear lighting system on the 3 is a well known troublemaker. For some reason Land Rover decided (Ford do this as well, in fact that's likely where the idea came from as Ford owned LR at the time the LR3 was designed) to run one brake switch with dual contacts. On set of contacts for the lights and one for every thing else. The lightning system is not monitored but the other systems are and here is where the problem lies. If a bulb is used with a different resistance or fits in the holder in a different orientation and fails it causes issues in the monitored systems through the brake switch.

So I removed the offending bulbs and started the engine. Bingo! All systems are a go.... Result!

So the moral of this story is the more warning lights you have illuminated the less likely it is that repairs will be serious. The amount of repair information and parts out there now on these vehicles compared to just a few years ago is vast. So if you fancy a newer model an LR3 is not totally beyond diy repair. 
No Road Except For Land-Rover.

Red90

This similar thing happened to Kirk on our trip this summer. The truck would randomly shut down the special programs and he would lose diff locks, traction control, HDC and ABS, normally in the middle of something difficult. He had a brake light out. Nobody in their right mind would have ever joined these two faults.  After the trip a little internet search showed this to be the case. Just using the North American version of the bulbs is enough to make the entire truck lose it mind randomly for no reason.

So, to everyone with one of these "well" designed trucks, buy a case of Lucas branded P21/5W, part number LLB380 bulbs and pass them around to friends.

Trevor

Hehe, nicely done Matt. Those boys down at Satek are going to be dragging you down to work for them for sure now.
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binch

wow....taken out by a light bulb!??!?!   :o

Great job sorting that out and better yet to share the experience and info!  Thumbs up!!!!
Cheers, Bill

Red90

Quote from: Matt H on May 13, 2020, 12:52 PM
For some reason Land Rover decided (Ford do this as well, in fact that's likely where the idea came from as Ford owned LR at the time the LR3 was designed) to run one brake switch with dual contacts.

Apparently, the brake switch is a Ford part and have a high failure rate. Probably worth replacing.  They appear to be quite cheap. I'm guessing they get carbon dust connecting the two switches.

Land Rover part number is XKB500110.
Ford part number is SW6572.

Matt H

Quote from: Trevor on May 13, 2020, 05:14 PM
Hehe, nicely done Matt. Those boys down at Satek are going to be dragging you down to work for them for sure now.

After fixing snow plows for the last few years I may just take him up on his offer lol.

I'm so over being cold for 8 months of the year.
No Road Except For Land-Rover.

Matt H

Quote from: binch on May 13, 2020, 10:36 PM
wow....taken out by a light bulb!??!?!   :o

Great job sorting that out and better yet to share the experience and info!  Thumbs up!!!!

I credit the internet, so helpful.

Now these vehicles have been in the wild long enough to get into the hands of large numbers of DIY folks that couldn't afford them when they were new, more of the 'unique' design problems have been figured out and the details shared.

The good news is the engines fitted to the 3 are substantially more powerful and reliable than the late Rover V8's in the previous model.
No Road Except For Land-Rover.

Matt H

Quote from: Red90 on May 14, 2020, 12:47 PM
Quote from: Matt H on May 13, 2020, 12:52 PM
For some reason Land Rover decided (Ford do this as well, in fact that's likely where the idea came from as Ford owned LR at the time the LR3 was designed) to run one brake switch with dual contacts.

Apparently, the brake switch is a Ford part and have a high failure rate. Probably worth replacing.  They appear to be quite cheap. I'm guessing they get carbon dust connecting the two switches.

Land Rover part number is XKB500110.
Ford part number is SW6572.

Yes, I always point out to the brand faithful (any brand, not just LR) that often the parts that make up their beloved vehicles are shared among many others including makes and models they don't rate very highly.

The UK based disco3.co.uk site is an excellent resource for anyone that owns an LR3/4


https://www.disco3.co.uk/forum/
No Road Except For Land-Rover.

Matt H

Now just to add to the seeming unrelated fault causing transmission issues saga, I had to fix the ZF EAT in my 2003 Discovery 2 the other day that was stuck in limp mode with flashing M & S lights. After many an hour looking at wiring diagrams and circuit library with a multi meter in hand, turned out I only needed to run an extra wire from the engine bay fuse box battery terminal to the alternator. It had developed a slight resistance in the fuse box buss that tripped the transmission into fail safe!  :o
Surprising as the car had always started and run fine with a good battery and alternator.
Even in what is now considered an 'older' Land Rover, the amount of systems that are monitored and have a bearing on fail safe parameters can be surprising.


I think I shall have to go and play with Series gearboxes for a while. At least when they have problems the cause is actually something to do with the Gearbox lol.
No Road Except For Land-Rover.

binch

Quote from: Matt H on May 26, 2020, 10:50 PM
I think I shall have to go and play with Series gearboxes for a while. At least when they have problems the cause is actually something to do with the Gearbox lol.


ROFL ;D
Cheers, Bill

88Hillman

John, I think another part number for the Motorcraft brake switch is 7E5Z13480A.