Fuse keeps blowing on Tomtom cable – ideas?

[FreeLitres]

My Tomtom ONE has worked faultlessly for a number of years but a couple of weeks ago, it blew the 2amp mini fuse in the cigar lighter plug/cable. I replaced this with another 2amp mini fuse and this blew again when I tried to use it.

I really needed to use my SatNav for an important meeting, so I chanced a 3amp fuse as a temporary measure. The cable seemed to work (ignition on, but engine off) so I set the address. As soon as I turned the engine over though, the fuse blew again.

I was running really late by now, so I stuck in a 15amp fuse (yes, naughty, I know...), turned the engine on first and then plugged it in. It seemed to work ok for the journey.

When I got back, I noticed that the cable was warm to the touch which I had never noticed before. I don’t want to risk using it again like this.

Any ideas what could cause these symptoms?

Might my cable be broken/shorting after years of wrapping and straightening it?

Can a car somehow start sending too much current to the cigar socket when turning the engine over?

If I buy a new cable, is this likely to solve it?

[defblade]

FreeLitres said:

Might my cable be broken/shorting after years of wrapping and straightening it?

If I buy a new cable, is this likely to solve it?

Yes and yes

[FreeLitres]

defblade said:

FreeLitres said:

Might my cable be broken/shorting after years of wrapping and straightening it?

If I buy a new cable, is this likely to solve it?

Yes and yes

I hope this is the case. There are no obvious kinks or splits in the cable. I never pinch tight bends in the cable, just loosely wrap it around my hand.

[thegman]

Had the same issue. Bought a new one. No problems now

[GKP]

Use your Tom Tom to find the nearest Halfords and buy a replacement cable. It'll work out much cheaper than having to buy a new Tom Tom or new car.

[Camaro91]

FreeLitres said:

When I got back, I noticed that the cable was warm to the touch which I had never noticed before. I don’t want to risk using it again like this.

Your cable was warm because there is a fault current flowing through it, either an internal short on the sat nav or more likely, as you say, a short across the positive and negative cores in the lead.

The outer sheath might look OK, but the two cores inside are usually very delicate.

By allowing the fault current to rise as high as it has (by installing the 15A fuse), the cable itself starts to dissipate more heat, if the cable has been designed using the protection value (2A) then anything above that is going to start making it warm :P

Try a new cable!

Edited by Camaro91 on Monday 22 November 13:37