RX300 Brake Lamp Failure

Delphius1 · August 22, 2018

Got told by the boss the other day that my nearside brake lamp wasn't working. On the RX300 the brake lamp unit is actually a series of LEDs and not filament bulbs. So it's unusual for something like that to fail.

After a bit of a faff I got the light unit off and the LED module out of the lamp unit:

Only 2 of the LEDS are working, the rest are glowing dimly. Keen-eyed readers may see I've tried to solder the legs to get a better connection, but to no avail. It looks like the LEDs are worn out and have gone higher resistance in their old age. The bad thing is that 12v is fed via a resistor to a pair of LEDs in series, so if one goes high resistance, the pair stop working. I'm down to the last pair of working LEDs, the outer ones at 12 o'clock and 2 o'clock.

I'm looking at options to replace it. I can see there are non-Lexus light units available made by Depo, but I'm not sure how accurate a match that is for the original.

I might have to call my local dealer and find out how big a loan I have to take out to get an original replacement.

Pity we're not in the USA, they're freely available on the internet over there. Takes me back to my Supra days when I ordered parts from the US because they were (a) easily available on the net and (b) half the UK price even with tax and duty.

For reference the Toyota/Lexus part number is 81563-48060 for the L/H unit. They are handed.

Edited to add: Luckily the local Toyota dealer can get hold of it, which is great because they are closer than the nearest Lexus one. Current price is £53.86 ex VAT.

Britprius · August 22, 2018

Why not solder in new LED's. Single high output LED's are available on eBay, and you can always adjust the resistor value to give the correct LED current.

I had to replace the rear light on my Prius a few years ago for the same reason, but with the Prius you needed to destroy the light unit to get at the LED's. The light unit for that
was £286.

John.

C Andrew Green · August 22, 2018

I guess another option might be to replace the LED's in your existing assembly. It appears to be made by Lumileds, try searching RS or Farnell (these two links are filtered to only show Lumileds products). Actually buying from RS or Farnell can be difficult as a private individual but it mi9ght help to establish whether the component parts are available.

Andrew

Delphius1 · August 22, 2018

I did think about fitting LEDs as a cheap option, but decent quality replacement LumiLEDs are a couple of quid each at least, so I'm already half way to the cost of a genuine replacement and I reckon the other half is worth the lack of hassle. What I might do later is have a play with the defunct unit to see if it's possible to ressurect it, even if I buy a couple of LEDs and replace one of the pairs to see if it's feasible. Just in case the right hand light unit gives up the ghost.

I've just had a look at the RS and Farnell links. I did look at the Farnell site yesterday and saw you can't get the same LED package as fitted to the original light unit. Everything is surface mount these days and trying to mount them on the metal plates instead of the original LumiLEDs is an issue. I did look at a few options, but the genuine replacement thankfully isn't a rediculous price. The Depo aftermarket light unit is virtually the same price.

Delphius1 · August 22, 2018

2 hours ago, Britprius said:

Why not solder in new LED's. Single high output LED's are available on Ebay, and you can always adjust the resistor value to give the correct LED current.

I had to replace the rear light on my Prius a few years ago for the same reason, but with the Prius you needed to destroy the light unit to get at the LED's. The light unit for that
was £286.

John.

Ouch, £286 for a light unit, at that price it's worth having a go. Luckily on the RX300 only the brake lamp is LED and the module is replacable. Looking through eBay I did notice the RX400h light units are all LED and sealed.

One quirk of the RX300 LED module is it has a 300 ohm resistor across the 12v feed. I wonder if the car was originally designed to have a filament brake light and the resistor is in there to stop the bulb failure module going nuts.