No rear lights, no heating, no satnav after trunk had a leak

LS430 · January 14, 2021

Good afternoon everyone, I'm having an issue with my 2002 Lexus LS 430. There was an unfortunate leak in the trunk, the car's been parked up for a few weeks so I didn't notice straight away. I've locked a heater in there for quite a few hours yesterday and now it's bone dry again. I know for a fact that all the bulbs are working, so there could be no issue there. Hazards work, however the stop lamps and tail lights, and the reverse parking light also doesn't. I've checked literally all the fuses in the car, all are in order. I've got in the car today, had it idle for about 40 minutes on the driveway, but the heater still blew ice cold air when I went to turn it off. The satnav screen doesn't work on "MAP [VOICE]" mode (it's just black), but it does show settings etc when that's selected. Does anyone have a clue what could this combination of errors lead to? Where should I start looking? TIA

cruisermark · January 14, 2021

Hello David

The sat nav drive sits on the left of the boot under the boot lining and the right handside houses the reverse camera and amplifier - it could be possible the water has go to some of these parts (certainly the satnav drive is located quite low) or they have been effected by moisture - I would remove the boot lining - start with removing the black cover near the catch and then follow your way round - and make sure everything is bone dry.

If its not the above then it could be a weak Battery - get your Battery checked.

And finally if the above 2 are ok then just try a Battery reset - i.e disconnect and reconnect Battery.

If the problem is the anything like the LS400 seal then you can either remove the seal, dry and refit with silicone or buy a new one - I think they are available on eBay

hope this helps

KolePaha · January 14, 2021

There should be a total of 5 fuse boxes in your LS. Did you check all of them?

LS430 · January 14, 2021

30 minutes ago, cruisermark said:

Hello David

The sat nav drive sits on the left of the boot under the boot lining and the right handside houses the reverse camera and amplifier - it could be possible the water has go to some of these parts (certainly the satnav drive is located quite low) or they have been effected by moisture - I would remove the boot lining - start with removing the black cover near the catch and then follow your way round - and make sure everything is bone dry.

If its not the above then it could be a weak battery - get your battery checked.

And finally if the above 2 are ok then just try a battery reset - i.e disconnect and reconnect battery.

If the problem is the anything like the LS400 seal then you can either remove the seal, dry and refit with silicone or buy a new one - I think they are available on ebay

hope this helps

Hey Mark, firstly thanks for the reply. Yes, I've noticed the satnav drive in the boot, I've removed all the boot liners, so now it's just bare metal exactly for that reason, to make sure everything is completely dry. My Battery should be fine, it's an Optima Red Top RTC 4.2 racing Battery from my RX-8 that I've taken off the road for winter. I'll try the Battery reset now, and I'll get the seal sorted as well as soon as it stops raining.

LS430 · January 14, 2021

31 minutes ago, KolePaha said:

There should be a total of 5 fuse boxes in your LS. Did you check all of them?

https://fuse-box.info/lexus/lexus-ls430-xf30-2000-2006-fuses-and-relay

Engine Compartment x2
Passenger Compartment x2
Boot x1

KolePaha · January 14, 2021

29 minutes ago, LS430 said:

https://fuse-box.info/lexus/lexus-ls430-xf30-2000-2006-fuses-and-relay

Engine Compartment x2
Passenger Compartment x2
Boot x1

That is a good start! After trying out Cruisermark's recommendation and it does not result in success, then I would recommend to look for short circuits (long and boring process). Here is a good instruction for it LINK. You should start checking with the circuits that are affected.

LS430 · January 15, 2021

Guys, we've done some measuring today and the light bulbs get 12V, both relays in the boot show 4.5 Ohm. I've noticed that there is still a little bit of dampness in the boot, so I'll pick up a dehumidifier tomorrow first thing and I'll lock it in the boot for a good few hours. Once everything's crispy dry, I'll start looking again at issues.

Mihanicos · January 15, 2021

Try removing the connectors to the affected circuits, clean them with contact cleaner and reconnect.

Contact resistance often develops o er time on low voltage circuits. Usually if you remove the connectors and reconnect, the frction between the individual contacts will do the trick. A circuit diagram is very useful in locating the fault.

Try finding the fault with the existing conditions. This way you will get to root of the problem.

Chris.

ambermarine · January 15, 2021

Remove the satnav drive from the boot and put in your airing cupboard for a few days do not be to aggressive in drying this unit out.

LS430 · January 19, 2021

Thanks guys for the replies, I've disconnected and reconnected all the relevant ones in the boot, nothing. I'm sure that these aren't individual faults, but actually all related. Rear Sunshade, SatNav, Tail Lights, Stop Lights, Reverse Light, A/C, Heated Seats, Fuel Door Opener, Fuel Gauge. Do these have anything in common as far as relays and such?

The SatNav I couldn't care less about Phil, it's the tail lights, reverse light and stop lights that prevent me from the car's last MOT. 🙄

KolePaha · January 19, 2021

These seem to have all in common with the fuse No1 in engine compartment fuse box No2.

LS430 · January 19, 2021

This is what I was thinking, however I've checked it and it's ok. And I've immediately after noticing this went to try the sunroof and that works...

Mihanicos · January 19, 2021

Check the earth connection to the non functioning items. Disconnect both Battery terminals and check the ground ( negative cable ) resistance to the non functioning items. It should be very low and not higher than 1 Ohm.

Chris.

LS430 · January 19, 2021

Guys, I think I may have found something... Any thoughts?

cruisermark · January 19, 2021

Ok

Put us out of our (my) misery - what is the problem? lol

BigBoomer · January 21, 2021

Without knowing what the circuit is those 5 fuses may not have a connection to ground. You'd have to either find a circuit diagram for them or else take that fusebox apart and trace the circuits yourself. What are those 5 fuses for? They could be connected to ground via a single large fuse that's blown, or by a relay.

LS430 · January 25, 2021

Gents, the culprit has been found.

The thing I should've done straight away, is to take the fusebox apart. Like...immediately after turning the lights on and seeing that something's up, and especially after finding a leak. Here are some pictures after the fusebox and the PCB has been cleaned thoroughly with isopropyl alcohol and a toothbrush. It looked absolutely filthy and definitely had some serious leak damage. I'm currently trying to source one on fleaBay to replace and hopefully that sorts all my issues out.

The-Acre · January 25, 2021

Wow, you've certainly got patience!

It might be worth contacting Paul Frost as he breaks LS's, lexussparesdirect, not to be confused with Lexus parts direct!

BigBoomer · January 26, 2021

I'd bet £10 that one of those 3 relays isn't completing the circuit and get replacements and solder them in.
If you can get a used spare, that should be good too.
If that sits in a low point that collects water, there should be a drain hole somewhere that is probably clogged up.
Why do car makers put electronics at the low point in cars?