Intermittent harsh ride problem solved at last. Hydractive

[isisalar]

I posted recently asking about the E crofting diode mod in an attempt to cure an intermittent harsh ride. Tantalisingly the car would sometimes be super super smooth and then the next minute become very harsh, particularly over drain covers, broken surfaces etc.
This is what I wrote:-
'Well, all the spheres have been renewed, bar the rear corners which are definitely ok, done the pump o rings, new feed pipe, new known good height corrector on the rear, do need to sort out the front one but it's not bad, new dog bones, new genuine p bushes, drop links, front bushes and ball joints and it still seems to be a little too hard sometimes and sometimes very soft.'
Doing every one of those items improved the ride a bit, but still it was hard a lot of the time. Since the rear height corrector was done, which made a massive difference, I'd worked out that leaving the car ticking over for more than a few minutes, or parked for a while, resulted in the super smooth ride for at least a while before the harshness resumed(mostly).
Yesterday I decided to re assemble the tailgate trim, after an unsuccessful HRW repair attempt, started before it got cold last year and while I was there something that Dickie G had mentioned to me many years ago came to mind. A microswitch, attached to the tailgate lock tells the ecu that the boot is open or shut and it was a good idea to cable tie it closed. I knew the switch was dodgy because it had been triggering the alarm, so a Lexia said. I cable tied the switch and re assembled.
Had to do a longish drive yesterday and astonishingly the supersmooth suspension didn't fade away, this morning the same. It has dawned on me that Richard might have said that the suspension goes into hard when the tailgate is open, which would explain a lot.
Of all the things I've done I would say that this, by far, has improved things more than any other and will be the first thing I check if I ever get another Xantia.
The thing I find strange is, considering the amount of questions about harsh suspension that get asked and answered on here I can't recall this ever being mentioned.
Off on the same long drive again today, really looking forward to it.
Cheers
Paul

[Mandrake]

Sorry to be the bearer of bad news Paul, but if you're referring to the switch that's below the tailgate latch which pushes to the right when the tailgate catch plastic surround is pushed down, it can't possibly be related.

That switch is only used by the alarm to set off the alarm, it does NOT go to the Hydractive ECU, nor the interior light. In the lifting part of the tailgate is a tilt switch which operates the boot interior light, (switch 3100 in the wiring diagrams) and the Hydractive ECU piggybacks off this switch not the alarm one.

Also, the purpose of that switch for the Hydractive system is for the "anti-jolt" system. If the tailgate is left open while the ignition is off the electrovalves will be switched into the soft mode for a maximum of 10 minutes, from memory. This is so that pressure to the middle sphere is allowed to equalise when loading or unloading the car. When the tailgate (and all doors) are closed the system goes to hard mode after 30 seconds instead of the 10 minutes when a door is left open.

So the boot being opened puts the suspension into soft mode, not the other way around. The tailgate and door switches make NO difference to the hard/soft switching when the ignition is turned on and the car is being driven, they only have an effect when the ignition is off.

So whatever it is, its something else, or just a co-incidence with an intermittent fault!

[Mandrake]

Is the ride still smooth Paul ?

[isisalar]

It certainly is Simon, did the same journey yesterday and all good and at last consistent.
The micro switch I'm talking about is not under any plastic cover, it's attached directly to, by a plastic lug which quickly wears away, the latching mechanism on the tailgate. It's a spring loaded plunger type arrangement similar to a conventional door light switch but smaller. The tailgate liner panel needs removal for access.
It was when I first had my VSX that I took it to Richard for a Lexia session and this picked up the switch not working. One of the problems I was having with it was that it would flatten it's battery, if left for more than a week. It was explained that with the switch giving an open signal the electrovalves were constantly switching and this was causing the drain on the battery. Cable tie solved that.
Possibly things are different on the estate?
Anyway, very happy for now to have made such progress, just hope the harshness doesn't return.
Re the diode mod, is this likely to be necessary now, is this something like the ignition switch problem that was resolved with the mk2?
I've given the old front height corrector to a local motor engineering firm to recondition the turrets at their leisure, will let the results be known.
Cheers
Paul

[Mandrake]

The micro switch I'm talking about is not under any plastic cover, it's attached directly to, by a plastic lug which quickly wears away, the latching mechanism on the tailgate. It's a spring loaded plunger type arrangement similar to a conventional door light switch but smaller. The tailgate liner panel needs removal for access.

Yes that's the switch I'm talking about, the "plastic cover" I'm referring to is the tailgate liner panel. And yes, they are rather flimsy with the plastic lug wearing away...

It was when I first had my VSX that I took it to Richard for a Lexia session and this picked up the switch not working. One of the problems I was having with it was that it would flatten it's battery, if left for more than a week. It was explained that with the switch giving an open signal the electrovalves were constantly switching and this was causing the drain on the battery. Cable tie solved that.
Possibly things are different on the estate?

No, that switch is definitely for the alarm only.

It's the tilt switch in the tailgate which operates the light which triggers the hydractive system. Easy enough to prove to yourself - unplug that bottom switch which will make the alarm think the boot is always closed - then open the boot a minute after the engine has been stopped and the car will still switch to soft mode.

Probably the battery drain was due to the open tailgate signal preventing the alarm ECU from switching into sleep / low power mode.

Anyway, very happy for now to have made such progress, just hope the harshness doesn't return.
Re the diode mod, is this likely to be necessary now, is this something like the ignition switch problem that was resolved with the mk2?
I've given the old front height corrector to a local motor engineering firm to recondition the turrets at their leisure, will let the results be known.
Cheers
Paul

No, the electrovalve diode problem is still present in the S2 - the electrovalves are the same. So if you haven't done the diode mod its worth doing. One of the first things I did to this car when I got it!

[isisalar]

Been re reading your first reply Simon, and thinking what else might have changed to effect the transformation. The other things I did at the same time were, attempting to clean up the airbag connections under the passenger seat with contact cleaner, and replacing the plastic trim covering the wiring running down from the body to tailgate grommets. Both sides inside the grommets are a complete mess of crimped on connectors and broken wires, but all seems to function except the HRW and the wiper only operates with the washer. On the list of course, but so are a lot of other things. Could the answer lie here? The covers have been off for a while and it's possible that something could have been making or breaking a connection intermittently and now the covers are on it's not.
Can a Lexia read hydractive faults?
Slightly off subject, the airbag connector (brown) has responded to contact cleaner a few times but is now being a bit stubborn and the light comes on again. I'd like to give the connectors a good clean up and when working tighten up well with cable ties. what's the best way to clean these type of connectors?
Cheers
Paul