Bit of a long shot, but you never know...

The Father-in-Law and I have been trying to sort out Mother-in-Laws '99 Corolla, which has no tail lights, sidelights, foglights, air-con or dash lighting. Various fora have said to check the fuses and relays in the dash and engine bay, but these all seem fine. F-in-L (geddit? ) has the appropriate Haynes, which shows all the affected systems run off the same fuse and relay (WTF???), but not much more, and we've already checked them. I've noticed a slightly odd thing, whereby about five or six circuits all run through the foglight switch (WTF??? again), including the headlights, and the switch itself isn't latching. F-in-L reckons it's not that, which may or may not be to do with the 50 quid he was quoted by the Toyota garage for a replacement!

Anyway, just wondered if anyone knew anything. Despite the location of this post, an attempt to find the OBD-II port led me to a blanking plate, and the little box in the engine bay marked 'DIAGNOSIS' seems designed to have fuses inserted in it... :confused:

A '99 Toyota build for Europe will have its own proprietary diagnostics port using MIL flash codes, and not the 16-pin SAE J1962 port we are used to seeing on more modern cars.

In the case of this Toyota you need to bridge two of the diagnostic pins (E1 and TE2) and then E1 and TE1. Then count the flashes and decode from a flash-code table (you should be able to find that on the web).

As regards the lighting problem, I think you need to trace the fault through using a portable multimeter. Check for supply voltage after the fuse, then after the relay the at the input and then the output of the fog light switch etc., working your way along the circuit.. Use and pin to probe through a wire or into the back of a connector if necessary. At the end of the day its not rocket science, its just steady logical fault-finding.

i pressume you've tried bypassing the foglight switch to see if you can get any of the other circuits up?

Well, the above (other than the diagnostics) hasn't ruled out the switch, but has suggested an alternative faulty part - a mysterious thing with part number 90980-04066. It only has two terminals, and there's no continuity - either way, in case it's a diode - and it has 12V across it (plus plenty of current - DAMHIKT ) Of course, the Toyota parts desk was closed by the time we found it, and nowhere else we tried had seen anything like it! Toyota fora don't have a definitive answer for what it is, and it's not in Haynes or the manual. There are no amperage or polarity markings, but if whatever it is has blown, it's very sneaky of Toyota to have it unmarked IMO...

Edited 11 October, 200916 yr by ap0gee

I think you'll find that its a capacitor (for noise suppression) and therefore you should not expect continuity between the pins. I think you'll need to continue your search.

I think you'll find that its a capacitor (for noise suppression) and therefore you should not expect continuity between the pins. I think you'll need to continue your search.

first thing i was going to suggest too, or possibly a zenor diode acting as a debouncing protection for the switches/relays... i admit i'm way out of my depth on jap cars:O

A diagnostic test won't produce any codes unless the engine management light is on. That part appears to be a circuit breaker, from here:

What is this chunky black fuse that I found in my Corolla for? - Yahoo! Answers

That part appears to be a circuit breaker, from here:

What is this chunky black fuse that I found in my Corolla for? - Yahoo! Answers

Yeah, I found that too. But then also suggestions that it's a condenser (aka capacitor, like Hauptmann said), a diode (like Tom mentioned), and even a relay (even though it only has two terminals!)

F-in-L is going to the Toyota stealers to ask about it, and if it's any of the above, we'll keep looking.

I still think it's that blasted switch. F-in-L says he's tried bridging it, but as it has a common live and earth plus several pairs of wires, I think there might be more needed than bridging the pairs. I'm actually wondering if there's a relay actually in the switch, like for the hazards on a Fabia. Certainly Toyota want fifty quid for a new one, which seems steep for a simple switch, no matter how many circuits it controls... :ne_nau:

I have worked on Toyotas in the past they they do use these black two-pin devices for electrical noise reduction. They are capacitors. When they use diodes the case has clear polarity markings on it. If there are no markings then its definitely a capacitor.

Like I said, follow the circuit through with a voltmeter and you will find the problem. Poke and hope approach means you end up replacing 'good' parts.

Well, the dark evenings meant time ran out, so it went to an auto sparks, who diagnosed a relay under the driver's seat (supposedly.) Whatever, it works now - thanks for the suggestions!