Hello From Frustrated Is300 Sport Owner With Headlight Puzzle

[philndeb]

hello all, I have been reading through some of the threads on this site and there are obviously some very knowledgable peolpe who i hope can help be avoid being shafted by my local auto electrician who wants to dismantle the entire front end of my car before giving me a qoute!

I have a problem with the headlights, a while ago the main beams flickered and went out with a burning smell, i found a relay that was knackered (broken stalk) , lexus wanted £80+ for a new one so i ordered two from eBay in the states and replaced it, the original relay had two wires soldered to the broken stalk that go to another added relay that is connected to the positive feed of an ingnition igniter. when i replaced the wires as they were before i got no headlights until i flash the high beams, then the mains come on. they have now started to go out after a while and i have to flash the highs again to get them to come back on. i have had a poke around with a multimeter but i dont really have a clue what to look for. i have noticed that even with the lights turned off if i flash the highs both the mains and the highs come on which i am sure isn't right.

my local auto electrician said bring it down and leave it with us but we will have to take the bumper off and the lights out to check the xenons so it's a "big job" but i suspect a short or wiring problem so i don't want to have my pants pulled down by them!

I will try to get some pics of the relay that has been added and post them later today with any more details i can think of, i there is anyone who can guide me through some sort of fault finding process it would be very much appreciated.

[philndeb]

hello again, here is a pic of the relay that someone has added at some time, the feed from the igniter can be seen, the two terminals from the relay had wires that went to the light blue relay in the picture, i have placed the wires temporarily but it made no difference, i did not solder the wires in permanently as i don't want to ruin the new relay.

Does anyone have any idea why the non standard relay might have been addded or have any idea where to start looking for answers? thanks

[sparkystav]

Hi mate

The full and dips should both come on when you flash the lights. That's normal.

However your right there's and issue, it's the rear fog light switch or the theft unit. Do you lights come on when you switch the stalk to auto?

You could bypass the theft unit, but you'll lose auto lights, I'd have to check up on the fog switch.

[philndeb]

thanks for the reply,

Checked the auto and no dip beam, just side lights. Dips do not come on even when I flash high beam.

Why are the dips coming on and staying on when I flash the highs?

Any idea why another relay would have been added to the light relay ?

If you think it may be the theft unit where is it and is there a way of testing it or do i need to bypass it?

Thanks again for your help!

[philndeb]

hello again, I have taken the theft ecu out and it does indeed have burn damage on the pcb, the only ones on eBay are a slightly different part no. ( mine is 89730-53070 and the ones on eBay are 89730-53010 ) Some of the listings say that they come from is200's but will fit an is300, does anyone know for sure what the difference is and will it work?, many thanks. BTW it appears that the extra relay has been added so that the lights can only work with the ignition on so i think my car has at some point had the dreaded "lights on all the time syndrome" ( i will be checking the screen asap but everything appears to be dry atm)

[sparkystav]

Yeah same happened to mine, you can just bypass that part of the theft unit easy enough and then you don't need to buy a new one.

You'll lose auto lights though

[philndeb]

cheers stav, how do i bypass the theft ecu? phil

[sparkystav]

cut wire 1 - red/black and join to wire 12 - red/yellow

that will bypass the theft unit

[philndeb]

many thanks to Stav for your help, i managed to find a salvage replacement theft ecu with the right part no. , it cost me £80 but lexus wanted over £400 for a new one so not too bad, plugged in and hey presto, lights! all working perfectly. So what would have cost me at least £600 parts and labour from an electrician who wanted to take the front bumper off and take out the headlights to start with (i am doubtful that he would have ever found the real problem), cost me just £80 and a couple of hours fiddling which has given me some knowledge in-case the problem occurs again,

It is really good of you to share your expertise to help others, much appreciated!