When I was dash-off and had an issue with the RH blend motor the HEVAC unit did not move the distribution motor either in response to any of the buttons - but it would move the distribution flaps during the start-up test. Once the RH blend issue was resolved, the distribution function worked fine. Message is - don't panic - but as above, diagnostics is the key.

I just put the relay between U/ Blue and the H/L switch and it works no problem (still driving the coil of the relay from the cigar lighter). Like that it still leaves the ability to have Park lights on, so I may just leave things there, as I guess that function is of some use. The relay will end up in the centre console cubby, so it can easily be replaced, or just jumped, without pulling things apart

Does it matter which way round 85 and 86 were with a std relay? My bench test said no. (9V battery across the coil and measuring resistance across 30/87). I actually have 85 going to ignition anyway, so that's ok.

"Disconnecting the ground from pin 3 of C219 is no different to the headlight switch being in the off position, no ground signal being sent to the BeCM" - i thought the same - but really it's not as the ground wire is still attached to the switch - perhaps "the system" needs that ground whether or not the switch is on.

Anyway - i've replaced the original ground on the H/L switch and reconfigured my relay wiring to break the U/Blue wire instead. And then if that works/ I can be bothered I'll put a second relay on the OR to do the side lights

I think the pin type is a red herring (still interested for the future, if some has a reference doc for Connector make/ model).
If I put the lights on with ignition on and remove the relay I get the same flashing effect so the new pin seems fine - but the second you remove the earth from the H/L switch - either because the relay is inactive, or the relay has been removed then you get the flashing (the lights don't do anything with switch off). I'm assuming it is some sort of BeCM logic I have fallen foul of - so maybe it's just better not to try and interrupt the ground to that switch.

Any thoughts? I may just replace the original ground pin in C219 and see what happens if I put the relay on the OR wire to interrupt the headlight wire to the BeCM instead

I can disconnect everything at C619 and the car still does the flashing thing. The only thing I haven't done yet is take the new pin out of C219. The new pin I used (econoseal) was microscopically different from the original one, I'm just wondering if it's not delivering a good connection - but then how would the switch be functioning fine at ignition on, if it had a poor earth connection?
Is there a document somewhere which lists off the connector make & type of each connector?

Since I had my dash off, as I put things together I thought I'd give this a crack. But I've ended up with headlights (no side lights) flashing at ignition off (and HL switch on) !!

Easy enough to roll back if I can't solve it, but what I changed was pretty trivial:
i I depinned C219/3 Black (ground to E252) which goes to the Headlight (H/L) switch
ii I replaced it with a new pin/ earth wire going to a 4 pin relay
iii I put the other side of the 4 pin relay to the earth at C619/ Cigar lighter (which grounds to E621)
iv. to activate the relay I used the +ve and -ve of C619/ Cigar lighter

I can feel the relay come on with ignition on, and go off with ignition off. With ignition on, the switch functions fine. With ignition off and H/L switch on then the headlights and tail lamps (but not sidelights) flash as well as the interior lights (HVAC display, clock, dash), even if I remove the relay from its base.

Is it possible that the BeCM (mis) interprets the lack of earth at the H/L switch (ie when ignition is off) and then starts pulsing the headlights. The flashing command can presumably only come from the BeCM?

I'll think some more...anyone else got any genius ideas?

Fair comment !

There's a Vogue 50 one on ebay the guy wants 500 quid for !! It looks ugly anyway IMHO Dave, do you have any encapsulation recommendations?

i'm still "dash off" too... on the indentation on the top of the dash - there's the soft skin - and a layer of ABS straight under which would take a self tapper. If you drill it and self-tap it there's no reason why you should have an air leak (any more than every other join in the ducting), but you cd add some RTV if it was a concern. However the windscreen edge is a lot clearer than the cabin edge if you're drilling blind. I think i'd be tempted to use a good double-sided tape. The wires can come up through the centre vent, and follow the same route as the alarm/ sun sensor wiring

Replaced battery on my DMM and suddenly the range tests ok, moving the motor with 9V - anything from about 2k to 9k ohms resistance (motors fitted, so limited by the movement of the flaps). I also redid a pin on the LH blend motor and replaced the connector block. Now all is fine, no service book symbol.

I've got the new ones coming anyway, so I may just put those on to test them and see what resistance values they give. Thanks for the tip Leo, if I'm fitting them I'll open the new ones up for a quick check first. This UK house-arrest thing has put a damper on my P38 work as I'm now home-schooling two kids.

Thanks for looking Richard, I'll try with a different meter.

I have the dash off my RR.
Q1. The blend and distribution motors were 90% ok before I started (periodic service book symbol), but anyway, now that I have everything out the HEVAC is showing me “Feedback circuit on RH blend motor faulty” (or some such – reporting via Nanocom).
I'm not an electronics expert, but possibly know enough to be dangerous. I can move the motors back and forth with a 9V battery. I took the 10k ohm pot off the board of the RH blend motor (ie desoldered it), and it goes all the way from 0 to 10k ohms (measured on multi-meter), but when I soldered it back to the board it goes from 0 to 3k ohms mid-range, and back to zero again (measured at the circuit board) - looking at the ETM there is a dotted line going from the pot to the motor, so maybe something is messing with the way the DMM measures resistance. Thing is all 3 blend motors seem to be like that (I didn't remove the pots from all 3 though!!). I’m just measuring this on a Uni_T multi-meter 20k ohm range – the fact that all 3 are the same may just mean my meter’s getting it wrong. Or maybe my test is wrong (just measured between the white/ wiper and one of the reference legs of the pot)?
Anyway – if the feedback error is not due to a dodgy pot then what else ? wiring? I think I may scrap the RH blend motor anyway, as the case has been cooked by a hot heater matrix manifold at some point (although the innards look fine ) but the principle is so simple that it then annoys me I can’t crack it !! As future-proofing I'm considering just installing 3 brand new ones at this point - just because accessing the blend motors is such a PITA.
Q2. Has anyone had any luck freeing the Distribution mechanism - I've greased all the pivots i can see, but it's still quite stiff - the gearing in the blend motor shifts it without complaint though. There seem to be two black toothed wheels driven by the main grey one, how do the black wheels come off ? Pull hard? I found a link to someone who had dismantled the whole heater box to do this, which i'm not very keen on.

As luck wd have it I am "dash out" at the mo - as in HEVAC out, centre switch panel out, Dash instruments out... plugged the instruments back in - started on the turn of the key, so yes, no problem

Kultur- I'm not sure what you though I was dishing out, but I think I was being pretty polite and trying to be inclusive.

I've done plenty of off-roading thanks - in an SIII/ Defender/ Camel DIsco - I happen to prefer a Series/ Defender as a base for off road mods - I personally have no time for lifts/ snorkels on a P38, but winches and off-road tires no problemo. Poor Leolito - you completely hijacked his welcome thread

Tnx for the vid Morat - that was pretty impressive. Kultur- fight xenophobia with xenophobia, that's what I say, you must really get wound up by Top Gear. 90%+ of these off-road mods are just for on-road posing. There are a handful of people, like your good self, that make use of the mods, but i don't think Gilbert D was referencing you - us lesser mortals just end up watching youtube off-road videos. Anyway the P38 is a poor choice of off-road vehicle, for as long as you have the terminals of every electronic system in the car lying on the floor.

In these times of coronavirus, and social distancing, I decided to whip the dash off and dig into the HEVAC looking for the source of a noxious smell. The dash came off without too much trauma, I buttoned a shirt around the s/w, so didn't bother removing it. All I found so far was that the the foam gasket on top of the heater box was completely u/s. Now contemplating removing the heater matrix to take a look at the outside of it (no loss of coolant though) - for now I'll probably plug in the dash and HEVAC and see how the HEVAC powers up. Bunch of other things now i'm in there - put a relay on the earth for the headlight switch, fix my centre console where some idiot PO cut it open, grease up the blend motors, clean out the temp sensor and tidy up the routing for the wiring.

So far I fished a rusty torx bit, and a one pound coin, out of the heater unit with a magnetic pick-up, god knows how they got there

Had a look, and found the same bulge as you, injected a bit of RTV for now. And yes, the back edge of the sunroof has a bit of give, probably around 5mm

I feel exhausted just reading that. I hope you manage to get back to the UK alright

Ah OK, so 4 big ones, and is the smaller one, by the screw-in stud for the spare, also removable? I don't want to try and pull it out if not.

Smart that they worked out how to drain the spare wheel well after wading but not protect the BeCM

Tanis - your "cut the seal" fix... how's it bearing up? would you recommend it, and what did you use to fill the gap. Ive just remounted my old seal, but it may well have shrunk and so need a cut too