Bit of an odd issue (indicators) LS400

Connor2x4 · January 14, 2018

So my 400 has a strange issue with the rear indicators. They work when using the lock and unlock buttons on the key but don't work when using the indicators or hazards. It's only the rear. The original owner had some super bright lights installed above the number plate ( some of you may remember the picture I posted) but since I removed them at the rear and cut their power the indicators have been off ever since.

Today I was looking in the fuse box to try and see if it was anything easily fixed and found the wires where they were originally tapped into the circuit but I don't know what they were wired into, hopefully some of you may be able to help

In the first picture it's the empty slot on the far right where they were plugged. It's a chunky three pin plug

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ambermarine · January 14, 2018

Connor

It looks like the person who put in the bright lights as used the rear indicator circuit to power them up they will have been wired in series so when you took them off line so to speak you also took out the indicators,

Without knowing what he as botched you could mess a lot of things up searching for the fix .

My advice is take it to an auto electrician who will sort it properly.

Connor2x4 · January 14, 2018

Connor
It looks like the person who put in the bright lights as used the rear indicator circuit to power them up they will have been wired in series so when you took them off line so to speak you also took out the indicators,
Without knowing what he as botched you could mess a lot of things up searching for the fix .
My advice is take it to an auto electrician who will sort it properly.

So do those three wires run just the rear indicators?

After a bit of research it seems a few 400's have suffered from faulty 'flasher relays'. Trying to pull out that relay to inspect for external damage has lead to me throwing my dummy out the pram as I just can't seem to remove it [emoji23] it's plugged in behind those three wires between the fuse box and the side of the vehicle frustratingly.

Before taking it to an auto elec is there any other advice before I do So? I suppose I could rewire the rear indicators back in but I'd rather do the easier fix if possible

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The-Acre · January 14, 2018

4 minutes ago, ambermarine said:

Connor

It looks like the person who put in the bright lights as used the rear indicator circuit to power them up they will have been wired in series so when you took them off line so to speak you also took out the indicators,

Without knowing what he as botched you could mess a lot of things up searching for the fix .

My advice is take it to an auto electrician who will sort it properly.

I second that.

Connor2x4 · January 14, 2018

So do those three wires run just the rear indicators?

After a bit of research it seems a few 400's have suffered from faulty 'flasher relays'. Trying to pull out that relay to inspect for external damage has lead to me throwing my dummy out the pram as I just can't seem to remove it [emoji23] it's plugged in behind those three wires between the fuse box and the side of the vehicle frustratingly.

Before taking it to an auto elec is there any other advice before I do So? I suppose I could rewire the rear indicators back in but I'd rather do the easier fix if possible

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Also it was just those two wires that were spliced into. They ran directly to the boot where the old units were. As the unit was defunct anyway I just cut the wires but it was only those two and a ground further down

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dendonc · January 14, 2018

6 hours ago, Connor2x4 said:

They work when using the lock and unlock buttons on the key but don't work when using the indicators or hazards.

Have you/will you try just locking & unlocking it manually for a couple of days and see if it alters the situation.

Connor2x4 · January 14, 2018

Have you/will you try just locking & unlocking it manually for a couple of days and see if it alters the situation.

Can give it a Try, what would doing that do different to remote locking ?

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Newbie1 · January 15, 2018

A lesson in not messing with auto wiring unless you know what you are doing! Good luck. Those relays are a pig to remove.

Connor2x4 · January 15, 2018

A lesson in not messing with auto wiring unless you know what you are doing! Good luck. Those relays are a pig to remove.

It wasn't me that wired them in lol they were from the original owner almost 20 years ago!

Yes having found where it is I'm not looking forward to taking it out however if it means it's just one component that needs to be changed then it looks like I'm going to be upside down in my footwell again lol

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Newbie1 · January 15, 2018

I know. I've remedied other stuff like this over the years, too. And perhaps caused it!

steve2006 · January 15, 2018

According to the wiring diagram the front and rear indicators are wired in parallel so if the fronts are working there must be a break in the wiring from the junction connector J7 and earth.

Check for voltage on the rear indicator bulb holder ( the green wire with a blue stripe) and ensure the other wire (white with a blue stripe) is connected to earth.

If you would like a copy of the page send me your email address via a PM.

Connor2x4 · January 16, 2018

According to the wiring diagram the front and rear indicators are wired in parallel so if the fronts are working there must be a break in the wiring from the junction connector J7 and earth.
Check for voltage on the rear indicator bulb holder ( the green wire with a blue stripe) and ensure the other wire (white with a blue stripe) is connected to earth.
If you would like a copy of the page send me your email address via a PM.

Hi, thanks for your response, I was going to get the multimeter out but decided against it as I thought if they work sometimes it can't be to do with power reaching the bulbs. I will drop you a pm now as thay would be very helpful thank you

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Connor2x4 · January 17, 2018

Digging deeper into the issue it seems that those wires I cut out appeared to be part of the tow hook connectors. But the pins had still been pulled out to accommodate the green and red wire seen in the pictures.

Does anyone happen to know how the tow hook was fitted from factory as it's on the original invoice as an extra, but not sure how this explains the intermittent indicators purely on the rear.

The last thing I do would before I take it to an auto elecs is replace the flasher unit, any other advice ?

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ambermarine · January 18, 2018

The tow hook would not have been fitted in the factory,They are not geared up for that .

Although it was on the Lexus invoice at point of sale it would have been fitted at the dealership or farmed out to a specialist tow bar fitter.

As I said at the first inquiry take it to a auto electrician.

Connor2x4 · March 20, 2018

Resolved this issue!

Luckily at the college I study at there are 2 ex Lexus technicians. The issue was that the original towbar from factory uses an oem loom, the problem was that the previous owners had tapped into a source of power and added that to the towbar.

The towbar loom has been unplugged and the plugs are back to normal and now the indicators finally work as intended! I have attached a picture so you guys can see if you have anything similar fitted.

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