mikesands

.... But that's my problem I can';t identify what the control module actually looks like Mike

The light comes on on the control switch. Neither the seat base nor seat back heaters work on the driver's seat but both work on the passenger seat. Not sure whether this is relevant but the interior lights were left on and ran the battery completely flat. The seat memories had disappeared but my daughter thinks the seat heating was off before the battery went flat (I am suspicious about coincidences though). I restarted the car by connecting a moderately discharged spare car battery in parallel with the flat one while it was in the car. All seems good now with the battery, but could something have gone wrong with the seat heater as a result of the flattening or recharging of the battery? I've looked at that diagram a few times Colin, but it looks too simplistic compared to what's actually under the seat. One would imagine that it would be easy to simply unplug both 'seat heater controls' and swap them over, but I can't identify them in real life. Mike

Came across mention of this in another thread. The reason I ask is that after the 12v battery was run completely flat on my rx400H, the driver seat memories had gone but also the seat heater now doesn't work (passenger side heater is fine). There may be other things that are 'off' too but in this weather it's the seat heater I'd like to get back on. So is the 8sec reset likely to cure the problem, or any other reset that anyone knows about? Thanks Mike

I'd like to try swapping the seat heater relays between the two seats, but is it likely I can do this without removing the seats from the car? I can see two or 3 connectors that come apart, but none of them look like a relay. Also it's not obvious how to separate any of the connectors (I think there should be 3 year college courses in how to fathom auto electrical harness connectors 😀). Mike

All plugs and wires under the driver's seat look sound, and the single 20a fuse is intact (but that was bound to be as there's just one for both seats). Can't find the relays though. Mike

Passenger seat still works so presumably not just a fuse unless they have separate fuses. Read somewhere about wires under seat becoming disconnected so will check that. But also read that there are two separate relays and a good test would be to swap them over - can anyone tell me where these are (which fuse box and relay numbers)? Thanks Mike

well ...... yes the exhaust is definitely sorted, but the droning noise hasn't gone. And in another thread one poster suggests that might be a worn bearing around the mid-point of the drive shaft. I mentioned this to a knowledgeable independent garage who said yes it's possible but he wasn't so sure as I'm not getting any wobbling of the car. And the droning noise has been there for a couple of years without getting any worse. Could a bearing last that long if it was failing? I think I'm getting a bit fussy .... this car is amazing for 172k miles 😄 Mike

just an update on this. I took the car to an exhaust specialist (one-man band) in Middlesbrough and we looked underneath the car on his lift. The whole exhaust was in surprisingly good condition for 172k miles (and he said it wasn't stainless). Anyway the problem was being caused by a fracture around what he said was a resonance damping weight that Lexus have designed into the long pipe between two of the boxes. Today he sleeved that pipe all the way to the back box and welded the balance weight as accurately as he could into the original position. And it's worked. Much quieter. He's sending me some pics later which I will post. £200 total. Mike

Well the reason I still have my RX400H is that each time I have gone to upgrade, I have been completely underwhelmed by the ride quality on the later RX's. The model before this very latest one was somewhat better, but the original poster is correct - the first of the RX450H's were IMHO unacceptable. Lexus seemed to succumb to the idea that their target market wanted sporty handling vehicles - so firmer suspension and low profile tyres and the problem is compounded by the 450 car being bigger and heavier than the 400. What astonishes me is that at 172k miles my 2009 400H still rides amazingly on the same suspension and original shocks. Even though it was the final limited edition it still had the small wheels and fat tyres which of course helps. And I agree absolutely with Theo. Went for a test drive in a Jaguar F-pace recently and it was so appalling that at the second roundabout I turned round and drove back to the dealership. Salesmen said ' yes they are a bit firm'. Hah - what an understatement. Mike

I can't imagine what would trigger a noise with no warning symbol in the display, but my guess (ignoring that) would be a flakey switch on something like the parking brake, or the detection system in the front passenger seat for the seat belt use. Mike

Interesting ..... My RX400H seat produces a ripping pain across my shoulders on a long journey. Unfortunately I don't think it's the same cause as shown in the video, because I get the same pain after a similar number of hours on my electric bike or my motorbike, and I have always thought it was LACK of support rather than something digging in (which it couldn't be on the bikes of course). I think the top of the drivers seat on the Rx400 flares away from my back too quickly, so there is nothing pressing in the shoulder area where Mr Vlad is getting a problem ..... but I will have a fiddle around tomorrow and see if there's anything sharp in there. Presumably the seat back will come off in a similar way. Mike

acf50 washes off exposed motorcycle parts within 2 or 3 winter rides, so I assume it will be gone from the underside of a car just as quickly. It does however penetrate nooks and crannies and if those nooks are not exposed to a jet of salty water from the roads then it will do some good in those parts. XCP is a compound many motorcyclists are switching to. Mike

Is there any point in me doing my 400H at 177k miles when it looks pretty bad underneath at the moment? A guy who is welding my exhaust for me showed me a leaflet for Lanoguard and says he can apply it, but I wonder how effective it would be going on top of pretty corroded parts. Mike

yeah ..... i had found them all. Will try some soapy water and retest now Mike

I think I found them all but may not have done - particularly the front sensors. - are they hidden in the black grille? By the way - do I have to switch on parking assist for them to beep at all? Mike

yes - just been going through the user manual and realise that there's a lot missing when it's the Luxury Trim. Having said that it's got 18 inch wheels and a nice ride. Many of the options available on the F-sport are not what I want. Oddly I found this morning that I could accept the standard 6 speaker system (and I have ML in my RX400H). Having been caught by Lexus's absolutely dreadful and expensive satnav systems previously, I would always use my iphone, so that aspect of the upgrade options is irrelevant too. ..... But there were some other obvious stuff missing that looks as though I might pine for it. This car has nice grey leather though and most of the cars are funereal black. I hate the reversing camera in my RX and much preferred the beeping sensors in my previous LS and Gs. This RC has the sensors but there's a message saying they need cleaning - which I have done but the error is still there - any tips? Mike

so how feasible is it to DIY upgraded speakers if you are stuck with the 6-speaker system on the Luxury 300H? Mike

Had a test drive and assumed kids in rear seats would be OK (since they were in school at the time). But after double checking that the XK seats are NOT really viable it made me wonder about the RC. Good to know your thoughts. Mike

Hi all, I've got the chance of picking up a rc300h to sit alongside my ageing RX400H (177k miles and still brilliant). I was going to get a Jag XK but the salesman very honestly pointed out that the rear seats are totally impractical and showed me that a 10 year old would be most uncomfortable even if she could get in. So are there RC300H owners on here who regularly take youngsters in the back - one would need a booster seat I guess, and a third. even younger one (nearly 4), might need a proper kid's seat .... but if that can't be done that's not a deal killer, as it's the 8 and 10 year olds that I regularly run about. Thanks Mike

Thanks Brian - I have emailed them, and they aren't too far from me Mike

Hmmmm - it seems the fault was the 'temporary' fix my mechanic did about 18 months ago in the exhaust system. I shouldn't complain since it was only paste and it's lasted 18 months. But he says the back box of the system is fine and the top end is fine, but there are 3 sections of pipe in between that are paper thin and the flanges and joints are badly corroded. Does anyone know of a source in the UK where I could buy these bits? Just the one section of pipe that he has pasted twice was £400 from Lexus last time we looked at it. Thanks Mike

I thought I would open up the bonnet lid when I started the car this morning, and now I'm thinking the noise is more an intake noise. It definitely reduces after 30 seconds when the fuelling changes. And it seems to be coming from the mid/left side as I look into the engine bay from the front of the car (ie the side where the battery is but not that far over) Mike

Thanks - I will get those checked tomorrow Mike

When the car is first started from cold, the engine is so noisy that it sounds like there's a hole in the exhaust, after about 30 seconds it quietens down to about half the volume (but is still too noisy). After driving for a few minutes the engine noise level drops to about normal. Anyone any ideas what I should check? Mike PS - from outside the car the noise seems to be coming from high up rather than low down where the main part of the exhaust system is .... but I might be wrong

My post of a year ago highlights this issue. I am now at 2 years since the dealership noted the corrosion and its since gone through 2 MOTs Mike