Hi, my f16 fuse keeps melting in the engine bay. The fuse is for the central control unit for the lights on the right hand side of the car, when I change it, It could last for almost the year before going again, can't see any reason for this, any ideas? Or has anyone had similar problems? Thanks 

Is the fuse part melting or the blades burning?  Or is it the plastic body that's melting?

Hi, it looks to be just the fuse but it will melt it until only the 2 blades of the fuse are left sticking up, and Don't have a problem with anything once I change it everything works perfect for months again. It also seems to happen fast because I always keep a check on it and it's not melting over time, the fuse would be perfect and then the lights on the right side would stop and I'd know it was after going. Out of ideas, I just hope it's not the loom or something???

If there is a sudden overcurrent, the metal part inside will melt quickly.  If the plastic is melting this means there is a high current, but not enough to blow the fuse.  Are you sure the fuse fitted is the correct amps?  Are the blades discoloured?  Maybe the holder is corroded?  Water is your enemy here.  Check fusebox lid is intact and well fitting.

Sorry just at work will stick up a picture this eve when I finish. Well because the fuse is melting it has damaged the holder slightly. Fuse just went last night, checked it and all that was left was the 2 blades not connected to each other and all the plastic had just melted away from the middle to one side, one side held the shape of the fuse but the other side had only the blade left and plastic completely melted.

Can you add the car details to your signature?  It helps others to know the exact model you have.  

Sorry, it's 2010 2.0 tdi Skoda vrs, bought the car about 6 years ago, always had this problem tho, ive but 3 fuses in over that time and also I always make sure the fuse is 30amp

I'll see if I can find the correct value.  My owners manual doesn't say.

Edited 10 February, 20188 yr by kelper

Could do to find out what the fuse is for. I’ll have a look when we know the model..

 

Edit: its must be an Octavia considering we’re in the Octavia forum. 

Edited 10 February, 20188 yr by Jonny118118
Info

A quick bit of research:

Source: https://www.manualslib.com/manual/375247/Skoda-Octavia-05-2010.html?page=229#manual

Source: http://www.sturtevantauto.com/salvageYardNews/CommonHeadlightProblems

 

 

Good, we now know it's the correct fuse - thanks

 

The fault finding logic is flawed.  Removing the bulb can not prove that the wiring is OK.  From the bulb back to earth has no voltage on it when the bulb is removed!

 

(I'm not criticising Jonny)

Edited 10 February, 20188 yr by kelper

Gerardf, have you changed any of the bulbs to non-standard?

 

You could swap the headlight bulbs left and right and see if the other fuse blows.  Or just fit a new headlight bulb on one side where the fuse blows.  Maybe you have a faulty bulb.

 

30A seems a lot for lighting...........  that's 360 Watts which is more like a heating load or a pump.  Does anything else fail apart from lights?

Edited 10 February, 20188 yr by kelper

Yes lads it's a 2010 Skoda Octavia 2.0tdi 170 vrs. I might also add they are a mighty car never had a days bother with her, this was the only problem and it's always been like this, That's why I'm thinking It must be something small enough causing this? No fault codes, except obviously when it goes...

Well over the years maybe one or two bulbs have gone, but only ever put in the normal h7, the only thing modified in the car is a phone kit, which looks to be well done and I don't even use...

Sorry and also the f16 fuse is a 30 amp on the manual....

A 30A blade fuse will carry a 10% overload almost indefinitely.  But a 100% overload will 'fuse =' in 5 seconds or less.  I guess your circuit is sometimes overloaded, but not for long enough to melt the fuse part.

Edited 10 February, 20188 yr by kelper
changed % to 5

1 hour ago, kelper said:

Good, we now know it's the correct fuse - thanks

 

The fault finding logic is flawed.  Removing the bulb can not prove that the wiring is OK.  From the bulb back to earth has no voltage on it when the bulb is removed!

 

(I'm not criticising Jonny)

If you took the bulb out and it still burns then it’s the wiring?

 

we’d had a fuse blow instantly without the ignition on in a Ford Puma, turned out it was ABS wiring loom shorting. Took a while to find it like. 

1 minute ago, Jonny118118 said:

If you took the bulb out and it still burns then it’s the wiring?

That would mean the live wire to the bulb is shorting.

 

I’d check all the offside bulbs are correct, front and rear as F16 is for both. If they’re all alright then it’s either wiring or the central control unit. 

 

Fuses that slowly overheat (and melt plastic in the fuse or holder) are frequently caused by a high resistance contact between the holder and fuse or more usually at the connection of the cable to the holder.

Might be worth checking the other side of the holder for a poor connection.

 

Hi Gerard

Did you ever find the cause of the melted fuse ? I have the exact same problem.