RX300/400h Daytime Running Lights Sorted

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Finally got round to wiring the DRLs and I'm quite pleased with the results. You don't really get the full effect on the video (presumably the fault or limitation of the camera) but in reality, they work well. The DRL set was just under £12 from China and I think I spent another £8 or £9 on a couple of changeover relays to make sure they went off when the sidelights were switched on.

Just got to get round to refurbishing the headlamp units now as they're yellowing quite a bit. I've got a 3M Headlamp Restoration Kit for that but still need to get some UV-resistant clear topcoat/sealer.



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Hi Sorcerer.

Thank you for a very intereting post and photos.

I have been looking on ebay and there is a couple of companies in the UK who sell front spotlight replacements that have LED Halo on the surround which look quite good but I have to admit that your addition looks more simplistic to install.

I had a peek under the bonnet today and after removing the decour panels (!) I couldnt get my big hands in to reach the indicator lamp holders.

Did you remove the headlamp cluster complete to enable the installation?

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19 hours ago, rayofsunshinegbr said:

...who sell front spotlight replacements that have LED Halo on the surround

Ah yes, the front fog lights on the 400h are round aren't they? The ones on the 300 aren't so I didn't have that option, but if I had, I might have taken it.

Don't get me wrong, there's nothing hard or difficult about the ones I've fitted but as you've already found out, it can be quite awkward to get your hand into the required position. I've not exactly got small delicate hands and did indeed struggle but with a bit of perseverance, I managed it without removing anything other than undoing that one 10mm bolt securing the washer filler tube and just letting the tube lean down a bit.

Don't be horrified by the photos below - this is just a 'first fix' or temporary lashup just to make sure things work and that I like them. Now that I know everything's alright, I'll make a nice neat job of it (got some proper automotive cable and that ribbed conduit to run it in etc).

The car's flasher unit is designed to work with a certain wattage of bulb (21W) but the LEDs are much less than this so the CANBUS system thinks the bulb has blown and they start to 'hyper-flash'. The orange-coloured resistors you can see prevent this from happening and allow the indicators to work normally. However, they do run very hot so they must be screwed/bolted to a metal surface to allow the heat to dissipate and I've also spread some thermal paste on the bottom of them to facilitate this. I repair computers for a living and use Arctic Cooling MX2 thermal paste to mount the heatsink/fan onto the processor so I used a bit of this and it works really well - the resistors are running really cool now.

The two relays are there to ensure that the DRLs only come on with the ignition and also turn off when the sidelights are turned on so that no one gets dazzled by the DRLs at night. This requires a feed from the sidelights and although the passenger side would have been closer, it was impossible to get my hands in and work down there so I stripped a bit of insulation from the sidelight positive wire on the driver's side, soldered a new wire onto it and ran that round to the passenger side to relay 2.

It looks like a lot of work but it wasn't really, just a couple of hours and it was done. Like I said though, I've now got to tidy it up and do the proper job but it'll be a lot quicker this time. Question is, will it be quicker than just swapping your fog lights for direct replacements? I don't know. Depending on how the replacement lights are wired you may still have to install your own relays like I did and of course, there's cost to take into account. I think I've spent £30 in total including the conduit and everything to do the job properly, so I'm not sure how that compares to the units you've seen on eBay.

Anyway, if you decide to do it this way and you need any help or advice (circuit diagram for the relay switching, where to buy etc) just give me a yell.






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59 minutes ago, maurice1 said:

Looks well

Thanks Maurice :smile:

Like I said above, you don't really get the proper effect in the video because I think the LEDs are too bright for the camera to handle, but in 'real life' they do work very well. I'm just ashamed to admit that I haven't got round to tidying the wiring up and doing the permanent job yet, just been too busy this week - but it'll soon be sorted :yes:

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I'm trying install DRL in my RX400h and can't find the source of +12V. The +12V should be only when engine is on or ignition key is set in position ACC.


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