Ls400 Series Iv - Gps Antenna Location?

[steve-bedford]

Hi All,

Does anyone know where the GPS antenna is for the satnav on the Series IV please?

Thanks in advance.

Steve

[alanr]

Hi Steve,

I'd always been under the impression that the satnav aerial was built into the rear screen along with the phone aerial, but having just looked in the handbook, I'm no longer quite so sure. There is a brief note in the handbook stating that objects placed on the dashboard may obstruct the GPS signal, so I can only assume that the aerial is somewhere just under the windscreen area. Perhaps someone with a bit more knowledge can come up with a definitive answer.

Do you have a problem with your satnav, or is this just a thirst for knowledge ? I note that worn tyres can affect the accuracy of the satnav - I really must find the time to actually read the handbook properly, and learn to use the satnav for its intended purpose. So far, I've managed to tell it how to take me home, but I already knew how to do that journey anyway. Life seemed to be so much simpler when everything was steam powered.

Regards

Alan

[steve-bedford]

Hi Alan,

I'm pretty sure the GPS antenna isn't built into the rear window. I do know that manufacturers usually build them into things like the door mirrors, bumpers, a fin on the roof or as you say under the dash - Anywhere that "can see the sky".

You should have a GPS sign in the top left of the display. What colour is it? Mine ranges from being out to red, to yellow to green. I'm guessing it's connected to the signal strength and number of satellites it can see.

All advice is welcome.

Thanks in advance.

Steve

[alanr]

Hi Steve,

I have been reading your threads during the last few weeks and had already taken on board the fact that you were less than happy with your 400. Off the top of my head, I really haven't the faintest idea what colour my GPS icon is, but if you give me 24 hours or so, I will get back to you with some concrete information. No icon means no signal, and I would suspect that the colour changes with day/night panel illumination.

You can do a manual calibration - see page 59 of the Nav system owner's manual. I have noted that the signal can be easily blocked by high buildings etc, and also gets confused by repeated direction changes. I do 2 right turns and 2 left turns in quick succession to get onto the main road about 100 yards (sorry, metres) away from my house, and my satnav generally takes about a quarter mile before the cursor aligns with the main road, instead of showing me being 100 yards away in a field.

I can't help but feel that your satnav problems may well be connected to all the water that's been sloshing about in your boot for goodness knows how long. The unit is basically a simple CD player, with extra attention paid to protecting it from excessive vibration. It isn't waterproofed, and certainly wasn't designed to operate in a humid atmosphere, and I suspect that that the CD drive may be a better place to start your fault finding investigation. I can probably rustle up an old CD of about 1997 vintage if you want to try another disc before delving too deeply. PM me if you want to try this route.

On DHP - I have driven two, and found them both slightly 'crashy' over rough road surfaces. With the standard 16 inch wheels and suspension the ride is about as good as you're likely to get without going to air suspension, although it is like trying to con an ocean liner around country lanes and roundabouts. Also, standard Dunlop D8Zs are still available for about £110. Sorry if that seemed like rubbing salt into wounds. The throttle is a bit of a b*gger, but I can assure you that you do gradually get used to it, although I did have the benefit of coming from a previous car with ECT. (Merc)

The thought was endearing, but I really couldn't recommend part exchanging against a traction engine, not only will you end up being divorced, but all your fillings will fall out from the vibration - been there and done it in years gone by.

I really do hope that your problems get resolved quickly - I suspect that your car may not have been treated too well in the past, and you are now having to put up with other peoples latent faults.

Regards,

Alan

[steve-bedford]

Alan,

Thanks very much for taking the trouble to reply.

[passman53]

In the hope that it may just be a bulb, do not get one from a lexus dealer.

I have a receipt for one that was replaced before I bought my car for £140!!! You can get a branded one, eg Phillips for around £70 off e bay.

[steve-bedford]

In the hope that it may just be a bulb, do not get one from a lexus dealer.

I have a receipt for one that was replaced before I bought my car for £140!!! You can get a branded one, eg Phillips for around £70 off e bay.

Thanks very much for the steer. I am very pleasantly surprised as both prices are much cheaper than I thought. Do you know the approx age / mileage of the car when it failed? My local Lexus dealer says it's very rare to have to change them.

[passman53]

In the hope that it may just be a bulb, do not get one from a lexus dealer.

I have a receipt for one that was replaced before I bought my car for £140!!! You can get a branded one, eg Phillips for around £70 off e bay.

Thanks very much for the steer. I am very pleasantly surprised as both prices are much cheaper than I thought. Do you know the approx age / mileage of the car when it failed? My local Lexus dealer says it's very rare to have to change them.

I would say 98% of the time the headlamp comes on perfectly, the remainder it tries to start (flickering like a kitchen light - you know what I mean) and then just gives up. Turn them off and back on again and go through the above procedure again.

The painful thing is that unless it's very dark, you're in front of a mirrored shop window or you are close enough to the car in front - you have to get out to check that it's fired - Very annoying - lol

The receipt (Lexus Milton Keynes) dated 7th feb 2007, Bulb £140.91, fitting £19.00, vat £27.98 = £187.89. Mileage at the time was 117,418. When driving you can see the newer bulb makes the other side seem a little bit less white but not enough to bother me and certainly not enough to warrant splashing out on another bulb.

[alanr]

Steve,

I've spent the last 36 hours driving around with my eyes glued to the satnav screen - probably at the expense of road safety. So if by chance I have swerved or driven erratically in front of anyone reading this, then I apologise profusely - mea culpa ! It's all been in the interests of science.

Firstly, colours of the GPS symbol on the top left of the screen. Mine also has different coloured moods, and I think your assumption that it is linked to how many satellites it can 'see' is a pretty good assumption - it's certainly very logical. Mine has four conditions, the only difference to yours being that my yellow symbol is actually blue. I should point out that I am using a slightly later software version than yours, which may well account for minor detail differences. Mine seems to work as follows -

No satellite signal - No GPS logo

1 satellite signal - Red GPS logo

2 satellite signals - Blue GPS logo

3 satellite signals - Green GPS logo (full triangulation)

My logo turns blue in built-up areas, and red when first starting up in narrow streets lined with tall buildings. It normally takes about 20 seconds from first starting up to working out who and where it is, but the initial 'where' is often about 100 yards out. That said, it's still a hell of a lot closer than thinking it's in Norfolk. Just as a matter of curiosity, was the location in Norfolk somewhere that you had actually travelled to, or is Norfolk a randomly surreal location travelled to only in the innards of your satnav ?

I have also tried driving around with my big thick trusty book of maps wedged in various places on top of the dashboard in an attempt to artificially block the GPS signal, but all to no avail - the GPS logo remained resolutely green. Bear in mind that I live in a very rural location, so green is predominately normal for me.

Things to check before spending any money or pouring petrol over the car and striking a match -

Drive out to the wide blue unobstructed yonder and see if the GPS logo turns green. If it does, and you are still in Norfolk, then my gut feeling is that the antenae is probably working OK, and that the problem lies in the CD drive somewhere. All the displayed information has to be read from the CD, and possibly the drive is sticking or freezing. If this is the case, then Norfolk is actually a fairly irrelevant place - it could just as easily have been Bournemouth or Carlisle. I should certainly speak harshly to the CD drive, or even chastise it, before taking the dashboard apart in seach of the antenae.

With regard to your Xenon headlamp failure, do check for slightly loose or corroded (high resistance) electrical connections at the back of the headlamp unit before splashing out on a new bulb. This type of bulb has a very long life and a very low failure rate, and the symptoms described are typical of a poor electrical connection.

Please do keep us all informed of progress - satnav faults are a learning curve for us all.

Regards,

Alan

PS I seem to have somehow inadvertently referred to Norfolk as irrelevant - does this mean I'm now going to get hate mail ?

[JellyBean]

PS I seem to have somehow inadvertently referred to Norfolk as irrelevant - does this mean I'm now going to get hate mail ?

Not from me, you won't. I moved up here from Twickenham 22 years ago to start a new job AND NOW I CAN'T ESCAPE. Helppp...

[steve-bedford]

Alan,

Thank you so much for going to all this trouble. I really didn't expect you to go to the lengths you have, but I'm delighted you did and it's much appreciated. Good advice thanks, I'll take a look at the weekend.

[steve-bedford]

This has a positive, igniton and earth connection and I do wonder if the engineer has taken a feed from a wire that is causing a poor system earth - We'll soon see!!

[alanr]

Hi Steve,

Have just read the latest update on your satnav - if my satnav is representative of the system, then it should find a satellite signal long before the 2 mile marker from your home. Mine takes about 20 seconds, even when blocked by tall buildings it always seems to find at least one satellite and display a red GPS logo at minimum. Unless you drive at the speed of light, then 2 miles is far too long. I can't fault your logic process now in thinking that it is antenae related.

Although I am a retired engineer, I belong to the old school of external combustion, and a lot of this modern electronic wizardry is quite frankly beyond me, although I do have a slight grasp of general principles. Your satnav has exhausted my meagre knowledge, and I am now reduced to clutching at straws. Your mention of having had a tracker fitted recently makes me pose the question as to whether they share any part of the antenae hardware, and if not, whether they somehow interfere with each other in a radiowave or electromagnetic sense. Is one set of GPS data signals being cancelled out or otherwise degraded by the other ? Do you know a friendly wizard ?

The fact that the satnav works on some occasions but not on others actually means that the fault finding process is more difficult. Intermittent faults can be an absolute nightmare to try and resolve in any sensible manner, they sometimes go away of their own accord, but are often found by a sheer random process coupled with a large dollop of luck.

I really do feel for you, and have stuck a quid in your fund ! Keep taking the tablets, and above all Nil Desperandum.

Regards,

Alan

[steve-bedford]

The tracking device has its own GPS antenna. That won't interfere with the vehicle's GPS antenna as they're purely dormant there to receive GPS. But what could be happening though (depending on how the tracking device was "wired in") is that it could be creating an electromagentic loop which is effectively what a GPS jammer does.

A random example here.........> http://uk.gizmodo.com/2006/11/18/gps_gsm_c...ammers_hit.html

Very popular amoung white van man who does not want GPS tracking telling his fleet manager where he is.

[steve-bedford]

Hi Guys,

For info - I called the dealer today (out of interest) to see the price for a replacement GPS antenna (fitted) on the basis that I could do some digging in terms of where it's actually located. The dealer said it was under the rear shelf then a colleague shouted over and reckoned that was the "older" version and that mine would be under the dash. I didn't get a great feeling of confidence from this so I'm not really any the wiser other than it's £300 for the part and £250 for labour.

Let's hope nobody ever needs one!!

[steve-bedford]

I think it needs an hour or so to "warm up".

[steve-bedford]

I had a response from Lexus GB at last.................

Firstly I apologise for the late reply to your email, we have been experience some problems with our new email system.

I can advise you thant the location for the antenna is positioned centrally under the dashboard, if there is anything else I can help you with then please contact me.