These are just some/many of my crude observations on the 3 amigos, battery voltage and other things. I can't back them up with codes since I was so busy during during these years, up until about a year ago, that I just drove my truck and used it as a tool in one of my lines of work (antique architectural salvage) and rarely paid much attention to it other then keeping the tank filled, oil changed and fluids checked.

When I bought my truck 03D2, back in early 07, it had the 3 amigos. At the time I didn't know what the 3 amigos were and thought those were just more pretty lights in the dash on these trucks so, I drove it with them on for a few months and didn't know any difference.

So this was around mid 07: First time I fixed my 3 amigos it was by accident and pure luck... I had noticed that when I would use the horn it would blow a fuse and take out the cruise control. I would replace the horn fuse and the cruise control would work again. I had no idea why but, I knew it was electrical so, thought it may be a grounding problem or something. This was before I knew anything about this or any forums dealing with land rover so, in an attempt to get to the bottom of it, first thing I did was check my battery cables and noticed the ground cable was a little loose. I disconnected and cleaned them, put them back on and I couldn't get the ground cable end to tighten up on the battery so, I bought a generic HD cable end terminal and put it on. I also cleaned all of the ground connections that I could find. I removed and sanded/filed the other metal end of the ground cable and also where it connects to the fender well. Put it back together drove it a few days and thought I had fixed the horn/cruise control problem (I later found out I hadn't) but I did notice the 3 pretty lights on my dash were no longer on. They didn't come on again for several years...probably around 2010.

Around 2010: My 3 amigos came on again and I went through the whole cleaning and tightening the cables and this time it didn't help. It was around this time that I needed new brake pads. I bought EBC dimpled and slotted rotors and akebono pads. I bought akebono pads because I had read that they would not put out so much brake dust and since my wheels were always black with dust I figured I would give them a try. I bought EBC rotors because I pull a trailer alot and thought they may be a good choice for stopping power. When I put them on, shortly after, I noticed my 3 amigos lights were off again. They didn't come back on this time for probably a year or two, we'll say 2011 since I don't know the exact dates.

Around 2011/2012: It was around this time I needed a new battery. I bought a new heavy duty battery, put it in and 3 amigos went out again and didn't come on again until a few days ago.

And finally a few days ago: I hooked up my trailer and was headed to new orleans to pick up a load of antique fixtures and noticed my truck was awful sluggish on take off and didn't feel right. I stopped at a store a few miles from home to fill up with gas and noticed my M & S lights were flashing (can't see them on the dash for the steering wheel airbag unless I am leaning forward).

I decided to head back home and stopped a few times along the way to look under the hood and truck to see that nothing was smoking or leaking. So I shut down and restarted my engine probably 3 or 4 times on the short trip back home. Along the way I got a warning from my ultragage and a code of P0705 and I also noticed my 3 amigos had returned but no codes were set on that.

So I came in and started reading up on the P0705 code ("Transmission Range Sensor Circuit Malfunction) and first thing I thought was that when I was replacing head gaskets a month or so back, maybe I had tugged on the wiring harness going back to the transmission or maybe I got cleaning fluid in the harness while cleaning everything under the hood. So after searching the forum and turning up plenty of hits pointing to the XYZ switch, I ran across a few threads on P0705 that mentioned low battery voltage.

So first thing I checked was the battery voltage on my UG. It was 13.7 idling which I thought was borderline since cranking voltage would be lower and may be the problem (not sending enough voltage to the transmission Control Module on start up).I remembered that I had removed my battery cables a few days earlier to fix a gas line leak at the rear and thought I may have not tightened the cable ends well enough. I also thought maybe since I hadn't driven my truck for a few days prior that the battery may be weak and going out...not holding charge.

Anyway, I cleaned and tightened my battery connections, cleared the code, cycled the key switch on and off a few times, started it up and all lights ( M & S and 3 amigos) were gone. After re-tightening everything I let it sit and idle about 15 minutes and checked my battery voltage again. This time it was around 14.10 idling. I headed off on my trip and kept an eye on my UG and dash lights and no 3 amigos and no flashing M & S. I have clocked probably 350 to 400 miles since then and probably 20 or so engine starts and still no lights or codes.

So I'm keeping my fingers crossed that it was a bad battery cable connection or weak battery this time and if the M & S lights or 3 amigos pop up again I will have my battery tested and probably buy a new one since mine is about 3 years old. I know batteries can last from a day to forever but, I think my problems, both M & S lights and 3 amigos, were something to do with the battery or connections this time.

Maybe this will help someone down the road with 3 amigos or even flashing M & S or P0705 code. I know they can pop up for many reasons but this is just how it has all played out for me so far.

BTW: My truck still blows a fuse sometimes when I use my horn and still takes out the cruise control with it. I still haven't figured that one out yet. I now only use my horn when I am out of sign language or yelling range.

Anyway, sorry it takes me writing a book just to say a few things, that's just the way it is with me. Probably why I'm about 10 years behind the rest of the world...I've spent 10 years trying to explain things that could have been said in much fewer words! Could be it's the only way I know of getting my point across now after 25 years of marriage?

 

Useful write up RicketyTick. Re the M&S lights flashing, the issue is the transmission goes into 'limp home' mode which is, I believe, restricted to third gear and feels totally gutless. I had these M&S lights occasionally and it was the xyz selector switch playing up but after removing it and drilling out the rivets then cleaning it out and resetting the internal contacts it was good. I also extended the A/C drain above it by 6" as originally it discharged over the xyz switch.

Defective batteries are renowned for causing all kinds of ECU glitches particularly when starting due the the high current absorbed. I'm on my second battery in 11 years but that is, eeeerrrr, getting marginal although the TD5 always starts immediately so probably saves my bacon most times. Next battery will be an HD Varta/Bosch or an Optima as they are better lasting although, as you rightly say, batteries are fickle and can last as little as a year or even last as long as a decade. Luck of the draw I suppose

 

Yea the XYZ selector switch was my original plan of attack. I was leaning toward drilling that out and cleaning the contacts when I stumbled upon one of your posts about possible low battery voltage and decided I would try checking that first. Since I got the flashing M & S and the 3 amigos all at once it was pointing to the battery. That fixed it for now..... time will tell. Thanks for that post, it saved my butt as I was already running late for my trip that day.

I do need to extend the A/C drain to get it away from any of that. I was thinking mine drained on the u-joints also.

This forum is a life saver...don't know how I ever got along without it.

 

My truck is not a daily driver so frequently the battery gets low. I had the 3 amigos pretty regularly last year. I put the truck in the garage over the winter and put a trickle charger on the battery. When I started up in the spring my 3 amigos was gone. I assumed it was just magic or luck. Recently i let the truck sit for a few weeks without driving (the battery is probably towards the end of its life) and it wouldn't start. I charged the battery to about 55% and it started so i drove it around. The 3 amigos came back. This was the first time i started thinking about a link between 3 amigos and battery charge. I fully charged my battery and for now the 3 amigos went away.

Not a lot of data here but my experience and this post above is making me wonder if a low/weak battery charge can kick off a 3 amigos fault. I plan on getting a better quality AGM battery for deeper cycling and will see if that help keep my three friends away.

 

The horn and cruise control are linked by some fuses, so I'm not surprised that your cruise goes out when the horn blows the fuse. The horns are in a really exposed place (right behind the grille) and get a lot of road debris and moisture pushed up in to the opening. One of the ways they can go bad is essentially shorting out. Replacing them is fairly easy (I upgraded to some Hella Supertones) and is worth your time, I was always a little nervous driving without a horn and now that I have a good loud one it really helps to umm...get the attention of the offending party...