DISCO4.COM - View topic - Fuses re the air suspension system

bbyer

Member Since: 25 Dec 2008
Location: Edmonton Alberta
Posts: 702

Side light out, eh!

That is the first time I have heard that a Hill Decent Control problem indication may have been caused by a non functioning side light. It is very possible however, given how the Land Rover computer system seems to sometimes respond to lighting faults, but that is a new one for me.

You make reference to towing a trailer. I assume the trailer has tail lights etc and that you plug the trailer lights into a plug at the rear of the 3. Do you know if the wiring and plug on the 3 is official Land Rover, or sourced elsewhere?

I ask this as the official Land Rover wiring, when properly connected to the trailer, is supposed to sense that something is connected, (assumption is a trailer), and then forbid the air suspension computer from changing the vehicle height. I note that this does not answer your question, but it does tell you what should or should not happen.

Re removing Fuse 35p from behind the lower glove box door, I wondered if you also removed F26e from the engine compartment fuse box. What I seemed to determine is that both fuses had to be removed to completly depower the air suspension computer. F35 is on the ignition and is alive when the engine is running, but F26 is alive all the time - it is on a full time battery feed and will power the air suspension computer and hence the exhaust valve, (the psst you hear as the 3 drops), at random intervals when the engine is off, as a part of the wakeup auto level program circuitry. What this means is that when you park the 3 and then later return, you could find it down on the stops. If so, it is the F26 fuse powering the air suspension computer in wake up mode, and then deciding that there is a problem, and hence releasing air from all four corners.

With the fuses out, and as long as the 3 is sitting at normal height, I regard the 3 as safe. As carverD3 has noted, for various reasons, the ride will not be as good, and therefore one can assume control not as good, but at normal speeds, all will be well - well much safer than crawling along on the stops on a public road. 2005 LR3 HSE 4.4L AJ-V8 petrol; Traxide Dual Battery; PIAA 2500K Yellow Ion H11 Fog Light bulbs; CounterAct LT-2 Capacitive Corrosion control; LLumar AIR80 Blue clear Infra Red blocking side window film; Liftgate manual release; Schrader Valve "air in" mod to OEM air suspension reservoir tank; Akebono ceramic pads; OEM solid vented discs; LR4 design hitch receiver; Wiggs D4 MOST bluetooth module; Clock on the Dash; 3 Flash signal light mod; Backup Camera; 2015/16 Nav Data update.

7th Jul 2010 2:02 pm

cazz

Member Since: 05 Jul 2010
Location: sheffield
Posts: 7

2005 Discovery 3 TDV6 Base 7 Seat Auto Santorini Black

I have removed fuses 35 3e and 26e and yes the tow bar was fitted by landrover. Air suspention on middle now with no loss of air noise

Last edited by cazz on 7th Jul 2010 2:43 pm. Edited 1 time in total

7th Jul 2010 2:40 pm

cazz

Member Since: 05 Jul 2010
Location: sheffield
Posts: 7

cazz wrote:
I have removed fuses 35 3e and 26e and yes the tow bar was fitted by landrover. Air suspention on middle now with no air reliese

and yes it has tail lights its a horse trailer

7th Jul 2010 2:42 pm

bbyer

Member Since: 25 Dec 2008
Location: Edmonton Alberta
Posts: 702

sounds like the work around works

What you are saying is pretty good news then. Removing the fuses seems to at least allow you to drive in a normal manner and at least go where you want to go.

Also re the Land Rover installed electrical towing harness, I think that they are also supposed to get their T4 unit out and tell the 3 that the wiring harness is installed. (Others disagree, and say that it is automatic sensing and that no T4 work is required.) Regardless, when the trailer is connected, there should be green trailer symbol illuminated on your instrument panel. The owners manual shows where the light should be. If you have the green light, then your 3 knows that a trailer is following behind.

As to what is actually wrong, the odds are that one of the wheel height sensors is defective, or more likely, the wiring to one of the sensors is defective. Land Rover created a kit that consists of a new wheel height sensor connector and about 6 inches, (150mm) of wire. The intent is that the repair person snips off the last 6 inches of cable and connector and then splices in the new kit wiring. Apparently the last six inches of conductor can internally corrode and then not send, or send false signals to the air suspension computer.

When I asked my dealer to install the kits on both of my front wheels, I also had new wheel height sensors installed as well. Note that the dealer apparently has to get the T4 out to reinstruct the air suspension computer as to the values coming off the new wheel height sensors. There are arguments to say that when changing only one sensor, the T4 is not required as the computer can learn from the old sensor on the other side, however there is not general agreement on that point. In any case, if both sensors are changed, then the T4 is needed.

If you have the Nav setup with the 4x4 display, call the display up and watch the action of the wheels on the display. With the fuses removed, the display will not show any wheel action, however if you put the fuses back in, then sometimes the display will show one wheel hopping about while the other three remain relatively stable. If so, then the odds are that the problem is with the hopping wheel electrical. As with all things Land Rover, sometimes that is the wheel that is OK and the problem is with one of the other ones.

What I will do in an attempt to see if the display is working properly, is find a curb or the like to climb and then manouver the 3 such that each wheel mounts the curb individually and see if there is any indication of that particular wheel rising on the display. With all working well, when mounting one wheel up on a 6 inch curb, the upward movement on the display is small, but it is detectable. 2005 LR3 HSE 4.4L AJ-V8 petrol; Traxide Dual Battery; PIAA 2500K Yellow Ion H11 Fog Light bulbs; CounterAct LT-2 Capacitive Corrosion control; LLumar AIR80 Blue clear Infra Red blocking side window film; Liftgate manual release; Schrader Valve "air in" mod to OEM air suspension reservoir tank; Akebono ceramic pads; OEM solid vented discs; LR4 design hitch receiver; Wiggs D4 MOST bluetooth module; Clock on the Dash; 3 Flash signal light mod; Backup Camera; 2015/16 Nav Data update.

7th Jul 2010 3:49 pm

GraemeS

Member Since: 17 Mar 2008
Location: NSW
Posts: 706

2010 Discovery 4 3.0 TDV6 SE Auto Nara Bronze

Re: opportunity to experiment here

bbyer wrote:
and re the F3E, fuse, I kind of doubt it even thought I said to do so - but it is still a question in my mind.

F3E is in the feedback circuit from the compressor supply relay so that the suspension ecu can check that the relay is working. The fuse exists to protect the wiring back to the ecu. Pulling the fuse will achieve nothing in terms of preventing the suspension from lowering.

7th Jul 2010 8:29 pm

landrovernovice

Member Since: 26 Jul 2014
Location: hunter valley
Posts: 2

2006 Discovery 3 3.0 TDV6 HSE Auto Buckingham Blue

Suspension problems- can someone please help

Hi All,

Hoping someone may be able to help us out. We have a Landrover D3 2006 vintage, HSE. We now too have a suspension issue and have been doing a lot of research into the possible causes. We are in a spot of bother due to me being on maternity leave and both of our cars failing at once- my husband car- a very old hilux has had numerous things needing to be replaced and the latest was a clutch and gearbox reco (which had to go back 3 times but that is another story!). This therefore is the worst time my car could play up too! We have been trying to solve the mystery ourselves.

I do a lot of kms and did notice quite sometime ago that after being parked the rear drivers side of the car would be very low resulting in the car being lopsided. But it did not affect the car when in use and never had a warning light- this was almost a year ago. Over the last few months though we have noticed that the car drops right down to bump stops when parked sometimes and is slow to pump up when you go to drive it, once pumped up, it was good though. About 6 weeks ago we went on a bumpy bush track and reasonably long drive and just before we got home the amber suspension light came on. After we parked the car, it did not come back on again. When the car was in having a service not too long ago I asked the mechanic to look into it and he went over the car thourougly with soapy water and could not find a leak- although he said he did not look inside of the rear damper spring module (I assume this is where the airbag is located), he found the compressor was and still is working.
2 weeks ago the light came back on, my husband and neighbour checked the fuses and found the 60amp fuse in the engine compartment to be blown, so they replaced this and the relay- car worked really well after this for about a week, then noticed it was slow to fill again and then the light came back on, in fact intermittently went to the red light on Sat but back to amber and haven't seen the red light again.
Yesterday we took the compressor compartment out and checked the dryer- our silica beads were good and the unit looked like it was in farily good nick. The compressor is the old hitachi type.
We put it back together and the compressor is still working.
We think there is obviously an issue at the rear wheel behind the drivers side but we dont know how to get at the airbag or valves and sensors.
We have tried pumping it up, waiting until the compressor fills all the way and then pulling the fuses as even if we could disable the system until our $$$ were better that would be great but it still went down both if driven or left to park. What I really don't understand is if there is a mechanical fault at either the bag or line on the right rear wheel, why when the fuses are pulled and the air is theoretically trapped would the air go out of the whole car and lower all points to the bump stops and just not the right rear?
If anyone at all could help us we would be so appreciative. Or if anyone is near the Hunter Valley in NSW Australia that would be amazing.
Thanks in advance, Selena and Scott

29th Jul 2014 12:39 am

landrovernovice

Member Since: 26 Jul 2014
Location: hunter valley
Posts: 2

^^^^oh and the rear brake lights have been known to blow, not sur if they have been replaced with genuine parts

29th Jul 2014 12:40 am

bbyer

Member Since: 25 Dec 2008
Location: Edmonton Alberta
Posts: 702

leaks sort of inside the compressor box?

You have done a pretty thorough search of the problem areas.

I am surprised the air dryer is OK as about the only thing I can think of is the air compressor is working too hard. I figure that 60 amp fuse blew for a reason and it was probably the compressor just kept running but did not go down on the internal overheat shutdown but kept drawing more and more amps.

You said your mechanic is pretty certain there are no air leaks. About the only place I would look again is remove the lower cover from the air compressor box and soap sud the air lines right around the compressor and when they go thru the air box.

I have heard of leaks where one hard plastic hose rubs on another kind of almost inside the air compressor box.

Removing fuse F26E in the engine compartment should depower the auto air release circuits and everything else in the air system, hence any air leak should be mechanical in nature. I assume the air tank was soaped as well. I have heard that the older tanks are now developing leaks due to corrosion, both internal and external.

What is odd is that with F26E removed, the front and rear block valves should depower and hence close and no air should leak from any of the air springs. Instead, it seems that given all four go down, that both front and rear valve blocks are leaking - possible with age, and then the air from the air springs escapes in a line common line to all four air springs - that would be somewhere in the area of the air compressor.

I have a number of electrical and block valve diagrams in my gallery under a couple of air compressor or air system files, some of which you may not have seen before. They may be helpful - as I do not think my post here is much help.

I was encouraged to hear that the Hilux has its problems as well, however I do not suppose you see it that way either. As to vintage, 2006 D3, it may seem that way right now, but I regard my 2005 as near new - from the side it looks like a current 4 and from the rear, it is just a tail light colour problem - and I prefer the red. Yes, tail light bulbs can almost create the problems you have.

One other thing that will drop the 3 to its stops is if the wheel alignment is out or the steering wheel points one direction and the vehicle goes another. The steering wheel rotation senor pickups up the misdirection. The air release however happens when you drive, not when you are parked if it is a steering/alignment problem. 2005 LR3 HSE 4.4L AJ-V8 petrol; Traxide Dual Battery; PIAA 2500K Yellow Ion H11 Fog Light bulbs; CounterAct LT-2 Capacitive Corrosion control; LLumar AIR80 Blue clear Infra Red blocking side window film; Liftgate manual release; Schrader Valve "air in" mod to OEM air suspension reservoir tank; Akebono ceramic pads; OEM solid vented discs; LR4 design hitch receiver; Wiggs D4 MOST bluetooth module; Clock on the Dash; 3 Flash signal light mod; Backup Camera; 2015/16 Nav Data update.

29th Jul 2014 5:08 am

caverD3

Member Since: 02 Jul 2006
Location: Oberon, NSW
Posts: 6922

2012 Discovery 4 3.0 SDV6 SE Auto Fuji White

I seem to remember the fuse could blow due a poor connection or fault under the passenger side wing.
There is a a connector there at the back of the whhel well behind the lining which can fail.

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29th Jul 2014 7:42 am

Gazellio

Member Since: 08 Jan 2011
Location: Chilterns
Posts: 4130

2009 Discovery 4 TDV6 SE Auto Indus Silver

Over last few days I have had the dreaded air compressor coming on/staying on and Xmas Tree lights on the dash accompanied by LIMP mode. Pulled the Air Compressor fuse with car at normal height and its driving fine (normal) albeit with two small fault lights on dash. This should allow me to drive it until my garage booking on Friday.

23rd Sep 2020 9:37 am

Weedyapl

Member Since: 23 Sep 2015
Location: Melbourne
Posts: 81

2005 Discovery 3 TDV6 HSE Auto Zambezi Silver

Re: Air Suspension ECU F35 fuse circuit switched.

caverD3 wrote:

Not your imagination, mine had a fault and did the same. Feels like a tall go-kart with much less compliance in the suspension. I still did a 500km round trip icluding some far tracks and paddocks with it.
.

Thanks mate for confirming this. I've got a bad height sensor and its occasionally going to the bump stops every so often really annoying as I live in the country where its all 100 zones and no shoulder. Going to bump stops at 100, no where to pull over safely with a semi up your ass is not fun!.

Pulling fuse 26 makes it bong like a madman and still threatens to go to bump stops but never actually seems to. Aidan
=============

16th Apr 2021 1:06 am

leroymusic00

Member Since: 12 Jan 2021
Location: Carlisle
Posts: 143

2005 Discovery 3 TDV6 HSE Auto Cairns Blue

Fuse 26

Mine drops to the stops overnight - does removing F26 still allow you to change the ride height?

23rd Apr 2021 1:35 pm

bbyer

Member Since: 25 Dec 2008
Location: Edmonton Alberta
Posts: 702

Pulling fuse F26 in engine compartment fuse box.

Re pulling Fuse 26, the short answer is no.

Your 3 will probably still go down regardless if there are air leaks somewhere in the air springs or stuff ahead of the front and rear block valve.

See the file with over 5,000 views per the link below in my gallery. It provides a pretty good explanation of what pulling F26 does and does not do.

https://www.disco3.co.uk/gallery/thumbnails.php?album=3778 2005 LR3 HSE 4.4L AJ-V8 petrol; Traxide Dual Battery; PIAA 2500K Yellow Ion H11 Fog Light bulbs; CounterAct LT-2 Capacitive Corrosion control; LLumar AIR80 Blue clear Infra Red blocking side window film; Liftgate manual release; Schrader Valve "air in" mod to OEM air suspension reservoir tank; Akebono ceramic pads; OEM solid vented discs; LR4 design hitch receiver; Wiggs D4 MOST bluetooth module; Clock on the Dash; 3 Flash signal light mod; Backup Camera; 2015/16 Nav Data update.

23rd Apr 2021 2:00 pm