Cooling Fan fuses keep blowing (30 amp)

[jackconcord]

Whilst stop start driving in traffic yesterday, the temp. gauge started moving rapidly towards the red. Luckily I managed to pull over immediately to allow the engine to cool down. I checked the 30 amp fuse (no. 10) for the electric cooling fan, as I hadn't heard it running, & it was 'blown'. When I replaced it with a spare, the fan burst into life.
This is the second time this has happened (would you believe in exactly the same street!). The first time I wasn't so lucky - the expansion tank ruptured & I lost all the water. The reason appeared to be the same fuse 'blown'. The engine runs at normal temperatures most of the time - even in traffic, so the water pump & thermostat must be operating, but there is obviously some overload from the fan causing the fuse problem.
I wondered if any of you have experienced a similar problem? I am reluctant to take the car to my local garage as they're not great with electrics, & my local Jag main dealer is totally useless!

[J44EAG]

Suggest you start looking for damaged cable sheathing on the fan circuit. You may have a direct short to chassis ground. Vibration may be causing movement of cables against the chassis causing an intermittent fault which blows the fuse. As always, start with the basics first.

You might also check the current drawn by the fan when running and ensure that the fuse you have installed is large enough to cope with prolonged fan use in hot conditions. One of these units below placed temporarily in line in the circuit will show you exactly how much current is being drawn in real time. It takes all the guess work out of the equation. A highly recommended little gadget.

http://www.maplin.co.uk/p/400mm-automot ... &#overview

Mike

[jackconcord]

Thanks Mike (Sorry I haven't been able to respond to your helpful suggestions sooner, but I've been away for a few days in the 'back of beyond' without internet access & have just read your message).
I'll have a look at the wiring & see whether there's any problems there. I've just checked the fuses again & noticed that the replacement fuse has also blown on the way back from the place where the previous fuse blew!
A friend had also suggested that, due to low usage, the fan bearings might have corroded - causing them to partially seize & placing too high a load on the motors. However, the fan blades are rotating easily, so that obviously isn't the problem.
Hope it's something simple as you suggest.
Cheers,
Jack

[jackconcord]

Finally gave in & put the car into a local Jag. independent (Mcmillans in Motherwell). They diagnosed there was a fault in the small electric fan, & replaced it. Problem solved. I guess it proves the point that you can flounder around in the dark with electrics, but unless you have greater skills than I, it's sometimes quicker & easier to leave it to the specialists.

[mike020150]

It's always good to hear the outcome of a tale, good or bad, simple or complex. It helps us all when similar things occur and that's what the bulletin board is all about, sharing information. Mike.