Fuse mystery (to me)

Hi all

Both my headlamps failed on my way down to London this last week (2003 Corolla, 1.4lt, nothing-fancy model).

I had the high beams, and sides, and the M25 has street lights, so I survived (it was only when I came up behind the 3-mile long queue of traffic that I realised my lights had failed: no reflections in the car ahead).

Since both had gone together I assumed a fuse had blown (I was wrong, it turned out). The fuse box has two 15A blade fuses, marked "Head, LH" and "Head RH", and it has a larger, square hole for another fuse, which is

40A, and this is marked "Main". This hole is empty on my vehicle!

The very good people at Halfords[1] assured me that this was fairly normal, and that "it's probably a relay, fitted on models with fancier lights ... yours will all be on the 15amp fuses...." Are they right? I ain't too happy having an empty hole in my fuse box!

John

[1] I must say that I was very impressed with the Halfords staff btw: they were polite, helpful, pro-active in trying to solve my problems, and the girl who fitted the bulbs for me was brilliant. (I had given up in despair, having completely forgotten how I managed to do it last time, years ago. She did both bulbs with utter confidence in less than five minutes, working in spaces which defy entry, never mind manipulation.
Reply to
Another John
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They will use the same fusebox for a variety of models some of which will require extra fuses and relays. It is common to have empty slots in a car fuse box.

Reply to
alan

Bloody lucky if there's only one empty space. As Alan says, the same fusebox will probably be used for all models, including petrol/diesel, RHD/LHD, hatchback/saloon/estate, and allowing for different lighting regs for different markets.

Steve

Reply to
shazzbat

In article , Another John scribeth thus

Haynes manual needed perhaps?..

There is or might still be a girl up at Vindis Audi Cambridge in the spares dept, a real treasure she was too for being ever helpful:)...

Reply to
tony sayer

As others have said, fuse/relay boxes are designed to accommodate various specs and markets. In fact, I can't remember ever seeing one with all holes occupied on anything vaguely recent.

It's extremely unlikely that both dip filaments failed at exactly the same time unless there was a voltage surge. It's more likely that one had failed first, and was unnoticed.

If it was my car, I would have a look around to see if the headlight wiring had a common earth point, and if so I would undo it, clean it, replace it and then coat it with a suitable grease. However, that's probably only for the truly paranoid!

Chris

Reply to
Chris Whelan

It's Japanese. I have heard of people robbing Japanese cars for the whole electrical system.

30 years ago I had a Datsun Bluebird 910. It had brake light failure detection. If a brake bulb failed it lit a led on the dash. When a trailer was plugged in, it lit the led every time the brake was used thus confirming the trailer was still connected (and at least one brake light was working).

I'm sure other makes had similar and more extensive bulb failure systems.

Not that 1/2 the owners would do anything about it, just wait for the MOT and pay someone to change it during the pre MOT check.

Reply to
Peter Hill

I had the 140J then the 180B. I paid 300 quid for the 180B and it was worth every penny.

2/3 of owners won't pay for a pre MOT check.
Reply to
Mr Pounder

Personally I could never see the benefit of paying 'twice' for the MoT, particularly as the MoT tester's judgement plays a fairly large part in the process - thus possibly legitimately failing a car that has "passed" its pre-MoT (and after already having repairs done on the advice of the pre-tester).

Sometimes I think you far more chance of winning the national lottery than second-guessing some MoT testers on what will or will not fail a car.

Reply to
Woodworm

OP here:

Thanks for the replies chaps.

CW said:

The Halfords people said that actually it's quite common for both to go at once (although of course that may simply mean that people only come to them after the second one's failed, as you suggest).

One thing I didn't say in my original post (because it was already very wordy) was that the 'boot' clipped to the back of one of the lights had gone missing (god knows how), and thus the insides were exposed to the engine compartment. Given the weather last Monday (remember that?!), could it have been that wet had entered the light, shorted the bulb, and THUS blown the other light? Just asking.

Also BTW: I'm the world's worst at moaning vociferously about other drivers' buggered lights (off, or misaligned -- seems like 7 out of 10 these days!) and *therefore* I check my own lights very regularly. They were all fine before we set off for London (300m away).

John

Reply to
Another John

We're talking failed bulbs here. Is it too much trouble to back up to a wall at night, then check that your brakelights, rear lights, rear fog light, and then the ones at the front all work? People PAY for that?

Reply to
Davey

To me, the police should be more active in stopping people with misaligned headlamps. On the country roads that I use, I always worry about not seeing a black-clad unlit cyclist while I am blinded by oncoming vehicle's headlights, and these people are around here. The fact that it was partly the cyclist's fault still would not diminish the anguish.

Reply to
Davey

They have better things to do and it will get sorted in 12 months time at the next MOT.

I'm waiting for a legal limit on bicycle headlamps, new LED lamps don't dip and have a very bright beam. Mopeds that don't have dip were (are?) limited. About 15w IIRC.

Reply to
Peter Hill

I prefer a glazed store front. Fronts can be checked by the reflection on the rear of the car in front at traffic queues.

Apparently.

Last year I failed on number plate lamps. Both had failed and the bracket they mounted on fell apart. Doh!

Reply to
Peter Hill

Good choice.

They can also be checked, more reliably, by the owner in his driveway.

Tough. But you could have checked that yourself beforehand. Next time....

Reply to
Davey
[...]

I'm pleased you found the Halford's folk helpful in your situation, but suspect that their knowledge of things electrical is pretty limited!

IME (40-odd years as an electrical tech, although not specifically in the motor trade), it would not be particularly common for both bulbs in that type of situation to fail almost simultaneously.

As you have already discovered, the two circuits are relatively independent of each other; in fact, it's been a legal requirement for many years that they are arranged in that way precisely to minimise the risk of what happened to you.

If water had caused a short circuit, the fuse for that circuit would have blown rather than the bulb. There would have been virtually no influence on the other bulb.

It's just about credible that one bulb going open-circuit could have caused a tiny voltage increase overall that was enough to finish off a bulb near the end of its life, but I very much doubt it.

Chances are it was just coincidence, but if one fails prematurely, I would suggest getting it checked out.

I'm staggered by the disinterest most drivers show in this respect. I always used to let folk know if I noticed a light out as I followed them to a car park or whatever, but I constantly met with either distrust or indifference, so I no longer bother.

Chris

Reply to
Chris Whelan

They frighten the life out of me. Been a proliferation on my regular drive (Sheffield Bakewell), where they either cycle in packs with lights (sort of fine but slow other traffic), no lights or reflective clothing (I can only think it's a style and weight saving idea), or dazzlingly bright LEDs.

I enjoy cycling but there's no way I'd go on those fast rural A roads.

Reply to
RJH

Here in Cambridge we're very grateful for ANY lights on pushbikes as light-less bikes have been the norm for many many years now;!...

Reply to
tony sayer

At least IN Cambridge you have a chance of having street lighting.

Reply to
Davey

While checking my wife's car before it's MOT, I discovered that some bastard had stolen the nearside front foglight bulbholder - presumably as you can't buy them without the complete lamp at a dealer price of £74. The way they lock in, it's extremely unlikely to have just fallen out and even if it had, it'd still be locked to the power connector.

I know they're not covered by the MOT, but while I was checking, I was doing the lot.

I've picked up a complete lamp on Ebay now.

SteveW

Reply to
SteveW

I had an old CF van, I kept bootsale stuff in the back, one day I saw that someone had managed to bend the handle enough to open the back and a few things were strewn around from just inside the door on the right, nothing appeared to be missing and there was nothing particularly valuable in any case, so I put the things back, added a padlock and forgot about it, a month or so later I realised that the stolen item was a brake light bulb holder !! It was available as a spare part for about

2 quid !!
Reply to
Mrcheerful

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