Very strange noises from fuse box

[Telster]

Hiya all. Strange noises coming from my S2's fuse box!

It started off as a high pitch whine when I start the engine, then sounded just like someone tuning an old radio and then recently a very loud crackling. Thing is, the crackling continues for some time after the engine's switched off. Volume has significantly increased over last few days, so my hopes it would go away have not materialised! Traced the noises to the fuse box, but no further.

Don't seem to have any other symptoms - car is otherwise running very well. In fact, better than that - Promaxed it recently; don't know if it's related.

I've read about clicking noises from relays and poor switches, but this does not seem to be that. Anyone know which component it could be, or tips to further diagnose / fix? Ta!

 

[colin944]

I take it you don't have any burning smells? If you do have burning smells then stop driving it!!! If not then run the car take the lid off the fuse box and get your ear in there and see if you can locate the problem.Just a small aside is to check that you don't have a fuse or anything else stuck in the test point.Thats the only part of the system that I can think of that could produce weird noises etc without affecting anything else.

 

[J4CKO]

Mine sometimes has a relay type noise, like a little German spy is tapping morse code back to Stuttgart, seems to be the window relay, I call it "character". Doesnt seem to do it as much now, since I was messing about in the doors.

 

[pauljmcnulty]

I had this when moisture got in to the fan relay. I guess the easiest way to find out what's causing it would be to remove all the relays one at a time?

 

[Telster]

Sounds a plan. Would I need to disconnect the battery each time?

I had this when moisture got in to the fan relay. I guess the easiest way to find out what's causing it would be to remove all the relays one at a time?

 

[Mike_Pollock]

After a run take the top off and feel to see if ant relays
are hot

 

[repsol]

i would do this asap as sounds like somethings shorting in there or a relay is tired both could result in at least a breakdown at most fire

 

[Telster]

Yep - will do! Hope it's something trivial as have a road trip planned for Friday...
Thanks guys - will report back tomorrow with any findings.

 

[ukmastiff]

When i was an electronics engineer type 'everything' ran on relays.
I hope you have a good extinguisher !

On a more helpfull note removing relays is exactly how we traced such faults (in my case fruit machines first). What will decdive you is when u find a faulty relay buy a new one , fit it and the fault is still the same. then you look at socket joints etc.

Best of luck

mas

 

[bmnelsc]

ORIGINAL: ukmastiff

...
On a more helpfull note removing relays is exactly how we traced such faults (in my case fruit machines first). What will decdive you is when u find a faulty relay buy a new one , fit it and the fault is still the same. then you look at socket joints etc.

mas

Agree with this approach - I don't think you need to remove the battery cables - but a crackling sound is often the sound of electricity trying to complete a connection across some corroded contacts. When this is happening - the contacts are usually getting HOT - so it is worth your while to try to find these before you have melted wires, a melted relay, a melted fuse box or worse. It often doesn't take much corrosion - even a film can be enough.

You can try the listen test but you might find it more useful to pull each relay in turn and buff up the spade connectors. Often just pulling and re-installing will scuff through the corrosion and restore a good connection.

 

[zcacogp]

ORIGINAL: colin944

Just a small aside is to check that you don't have a fuse or anything else stuck in the test point.

What's the test point?


Oli.

 

[Mike_Pollock]

To test fuses

 

[zcacogp]

Well I never. I've never noticed anything like that in my fuse box. Ever. In fact, I think I need to check I have one right now.

Let me guess - you push the fuse into it and the green LED lights up if it is OK?


Oli.

 

[zcacogp]

Well. Every day is a school day. Thank you chaps - I've learned something new about my car!

(Was it worth going outside onto the street in my bedroom slippers to learn that? Yes, I think it was. [])


Oli.

 

[Eldavo]

You have different slippers for different rooms?

 

[colin944]

Yeh it does light up.But if you left something in it it would get hot and then I think mit would be capable of making noise.

 

[zcacogp]

ORIGINAL: Eldavo

You have different slippers for different rooms?

Of course. You don't?


Oli.

 

[Telster]

Heh heh.

Well, as was almost inevitable with these things, armed with forum wisdom and a plan to test, all noises disappeared last night! After a week of increasingly worrying noises - not a squeak!

Almost certain to return when I set off on my weekend roadtrip tomorrow though. I'll arm myself with an electrical toolkit and wiring diagrams. And perhaps a fire extinguisher would be a good idea!

Ta muchly all anyhow!

 

[vitesse]

Thought about keeping a mousetrap in the car?[]

 

[Telster]

Well, examining the box I did clear out a veritable nest of leaves and other detritus around it! Heater works a lot better now... []

ORIGINAL: VITESSE
Thought about keeping a mousetrap in the car?[]