Aloha after a long hiatus, a number of personal, professional and other issues has kept me away from the RR and from here as well. Sorry!
I had almost not used the car in these past months, very occasionaly. Obviously I kept the battery topped with the charger, and I must say the V8 rumbles to life every time even after 10 weeks without hesitation. Great!

Unfortunately, a couple of occasions I had to leave the car out of the garage in the street, and obviously after a couple of weeks battery goes dead. A couple of times I managed to resurrect it, wit some deep, slow charging, but last time I forgot the lights on (in spite of her beeping I neglected to check) and this time I think the barely 2 year old Varta is kaputt - by the way, I am VERY disappointed about this particular battery performance, I am never buying Varta again .... three days I am trying to get it alive but I think i done. Very bothering as this is a 'present' to the next owner, as I believe I will part with the car, I want to replace it with something more 'agricultural' I can go back to the woods again.... would love it to be a Landy, but ... will see ...

In the meantime what I've accomplished:

• finally got the front bumper repaired and painted, costed me a fortune for a piece of black plastic ... here a healthy bumper is unobtanium! Only to fit the fogs and I am done ...and I drive VERY carefully now!
• finally got around to have it professionally polished, first time since 2016 (urgh) ... if I have time next week I want to refit the emblems in the bonnet and rear tailgate, and I am planning to take it to a good PDR shop I got acquainted with, and that will be the end of the "bodywork activities" here ...

Here are couple shots for viewing pleasure ... note still with winter tires, sigh

https://1drv.ms/i/c/05b738b1c4563d88/EdQdeC56heBJn9ntLzOfDH4BFm3p9h4fN78nBy1VIPs90w?e=OvFsu6

https://1drv.ms/i/c/05b738b1c4563d88/ERwtTbpM2rdDlSxkbqfIu9YBBCzdpb_UcbtxEMyeuwbZ1A?e=pU9ypp

Not today but over the last couple of weeks. Back in August I replaced the AC evaporator and all appeared well, but it wasn't..... Now I install domestic AC systems and to be qualified to do that did a full F-Gas course which includes how a system works. A mate did the cut down automotive course which tells you how to do it but not the finer points of why you are doing what you are doing. He gassed it and the pressures didn't look right. If a system is working correctly, it should have shown around 150 psi on the high pressure side and 50 ish on the low side but it was showing low on both sides (like 95 and 15 psi). Normally that would suggest a low charge but as we had just put the correct 1250g of R134A into it, we knew that wasn't the problem. But it was working so leave well alone.

Only it wasn't working, or at least not as it should. After it had been run for 15-20 minutes, the book appeared on the HEVAC and it refused to engage the compressor. Leave it for a few minutes then start it up again and it worked but the low side pipe (the thick one) was covered in ice. It should be cold, but not that cold. Not only that but the compressor seemed to be running all the time. Consulting the course notes this suggested a restriction somewhere. As it is always advised that the receiver dryer should be replaced if the system has been open to the atmosphere or the desiccant will solidify, decided that must be the problem. Both of us missed the obvious in this diagnosis, the dryer is on the high side so a restriction there would affect high side pressure not low side.....
Ordered a receiver dryer, the gas was recovered, and fitted it. Regassed it and it was even worse! Now the high side pressure was still just under 100 psi but the low side, the suction side, was going minus down into a vacuum.

That would suggest a problem with the expansion valve or evaporator. The replacement evaporator had come complete with expansion valve but, due to getting at it being a bit awkward (up against the bulkhead behind the throttle linkage) I'd managed to cross thread the bolt that secures the clamp that holds the pipes on and buggered the thread so had taken the expansion valve off my original evaporator and used that. That had been working perfectly before so it couldn't be that which only left my replacement evaporator. Not wishing to dismantle the dash again, I bought some AC Flush, a cleaning fluid with so many hazard warnings on the container the label is only just big enough for them all. Disconnected the pipes and noticed this.....

So it appears that my receiver dryer really had been shot and the desiccant had been escaping. Cleaned it out, pumped the fluid through the evaporator. A couple of bits of dirt came out along with a lot of green dye and it seemed clear so, after removing the high side (thin) pipe and blowing it clear, put it all back together again. Mate turned up, regassed it, and the pressures were still low so that only left the expansion valve and we figured it must have been damaged by being hit by lumps of desiccant with 100psi behind them. Gas was pumped out yet again and the AC Off button left switched on. A Britpart expansion valve is £65 but a pattern part from an AC specialist company ( https://www.autoairconparts.co.uk/ ) did one for £25, so ordered that. That arrived the next day so took the pipes off again (at this rate I should be able to whistle and they will jump off on their own!), removed the expansion valve, fitted the new one and put it back together yet again. Went over to my mates place and we gassed it for the umpteenth time. This time the pressures were spot on, air at around 4 degrees was coming out of the vents and the Nanocom showed an evaporator temperature varying between 0 and 6 degrees.

The way it works is that if the evaporator temperature is above about 2 degrees, the HEVAC engages the compressor clutch. When it gets down to 0 degrees the clutch disengages and it starts to warm up from the air being drawn through it but as soon as it hits around 6 degrees, the clutch comes in again to bring it down. It does this ALL THE TIME, even if you set the desired temperature to Hi. The AC still works to dehumidify the air and the temperature of the air coming out of the vents is controlled by the blend motors directing air through or around the heater matrix. I suspect the only time the AC doesn't kick in would be if the temperature of the air being drawn in from outside is below zero. So, as well as reminding me of stuff I learnt when I did the course, I've learnt more about how the HEVAC system on a P38 works.

Good stuff Richard. I know you know way more about these than I do, but my understanding is that the AC does come on when you select Defrost/Demist no matter how cold the ambient temperature is.

Yes it does but it shouldn't allow the evaporator to go much below zero or ice will form on the outside of it which could potentially damage it. I'll have to wait until we get a frost, which if last winter is anything to go by, might be one day sometime in February, and see what temperatures are shown then. Don't have any plans to go to the In-Laws in Latvia this winter so can't test it in really low temperatures. I know you get cold weather in Canada, do you have a Nanocom to check yours out of interest?

Yes. Maybe I’ll remember to check it when it gets cold.

Not on mine as I've run out of things to do with them now I've got the red one running properly on petrol as well as gas, but on one I was asked to look at a couple of months ago.

The problem was a permanent SRS light but although the Nanocom would connect to all the other systems, it wouldn't connect to the SRS ECU. Checked the obvious things like the connector behind the RH kick panel and could find nothing wrong there so ended up taking the centre console out to get to the SRS controller. Checking there showed only 3.3V at the supply line. Traced it back to the fusebox and still only 3.3V coming out of that, in fact, there was only 3.3V at the SRS fuse. So diagnosed a failed fusebox. Grabbed another from a local breaker, fitted that, the SRS light went out and everything was working as it should.

Quite why there should only be 3.3V on one fuse was a bit of a mystery so I pulled it apart a couple of days ago. It showed signs of burning around the output pin of Relay 9 but everything else looked OK from the outside. Getting it apart and it was obvious that someone had been in there before and had cut the pins between the two boards to open it up. Unfortunately, when they'd put it back together, rather than replace the pins, they had just soldered the cut ends together.....

When I did my apprenticeship (many years ago), I was taught that solder is to give electrical conductivity and not mechanical strength but whoever had done it obviously missed that part. You can see from the pic above that some of the pins just had blobs of solder on the two halves but the solder hadn't flowed properly between them (there's at least 2 that are obvious if you look). When I came to cutting the pins again, at least a third of them just came apart. I'm actually surprised that it was only the SRS that wasn't working looking at the state of it. Some of the board connections had been re-soldered but it looked like they had been done with plumbers solder or a soldering iron that wasn't up to the job.

So, I ground down the solder and punched the old pins through the board to remove them so I ended up with nice clean pcb tracks to solder to.

Once that had been done, I went round any iffy looking solder joints and did them again and cleaned up some of the pins and relay/fuse contacts that appeared to have been damaged by water getting into it at some point. Folded the two boards back into place and clamped them so they were parallel and fitted new copper 1.25mm straps between the boards and carefully soldered them.

Checked to make sure there were no solder bridges between pins and put it all back together.

So now I have a fully refurbished fusebox for a later (99 onwards) V8 P38 (part number YQE103410, the one that is no longer available) which I did consider putting on eBay but decided that I may as well keep it until someone needs it.

I've also get one that has been similarly fettled for a GEMS but that is going in my stock of spares as I have 2 GEMS of my own and I may need it myself one day.

Maybe a dumb question but couldn't you use say solid core cable thus introducing some flexibility for future 'taking apart' shenanigans? I haven't had to repair one or anything similar on mine, just the footwell connectors delete both sides.

Not if it is still going to fit in the box. The circuit boards are the exact size to fit inside the housing so the connections need to be where they are.

If anyone has never seen the inside of a fusebox, have a look here https://web.archive.org/web/20180516002340/http://www.rangerovers.net/repairdetails/electrical/fusebox.html#dismant. There are two circuit boards that are connected together with wide copper strips so they open up like a book. Then there are the two rows of pins down either side that also connect the two boards together.

There are 3 part numbers for the GEMS fusebox. The original one (AMR3375) was prone to failure as some of the copper tracks on the board could overheat and eventually burn through. It was replaced with the second attempt (AMR6405) which was redesigned so the tracks that were prone to overheating were made wider and this one was fitted to '97MY cars. For the '98 model year (AMR6476), the design doesn't appear to have changed from the previous version but the copper tracks are thicker so increasing the current handling capacity. Whether a '98MY one can be fitted to an earlier car I don't know, I'd need one of each apart to compare the two.

For the Thor (YQE103410), they carried on with the thicker copper tracks so these are less prone to failure.

The diesel also had similar changes. An early one (AMR3376) which supersedes to AMR6406 (which was fitted to '97MY cars as standard) and AMR6477 fitted to '98MY cars. From '99MY onwards they got YQE103420, but for some reason they got another change very late in production so from VIN YA438098 they got yet another one, YQE000010. That isn't shown as a superseded part so no idea if that one will fit an earlier car (well, any of them will fit but whether they will work as intended is anyone's guess).

In all cases overheating relays cause the fusebox to fail as it overheats the connections in the fusebox so if any of them are starting to show brown marks, replace them with good quality 40A ones.

Are the petrol GEMS fuse boxes interchangeable?

The early AMR3375 (94 to 96MY) superseded to AMR6405 which was fitted to 97MY cars and they are interchangeable. I'm not sure if the AMR6476 as fitted to 98MY cars are compatible with an earlier car but the fact that the 97 version doesn't supersede to the 98 version would suggest there are differences and they are not a straight swap.

Thanks - I will keep an eye out for a decent 1997 one.