Early DEFENDER 90 Heater fuse

[Peter]

As the header states. I have an early Defender Ninety. With the old 27mm glass fuses (Halfords only sell 30mmk glass fuses).

The heater has had issues in the past blowing fuses - about 3 years ago. Got round it by cleaning up the fuse holder. Now after a day at Mud Monsters off-roading (Soft off roading) It has started again to blow the 10amp heater fuse.

4TH one down on the left column of bank of fuses.

The actual plastic has melted, but cleaned up the terminals and all was well for about 2 miles then it blew again. Change the fuse and blew immediately - bit of a light show at night - orange glow, glow some more - blue light - then no heater fan. Great. At least its warming up a bit, but need heater to clear screen of damp interior (I'm a gardener).

I have ordered a set (2x8) of rear connecting blade fuse holers from Demon Tweaks as per http://www.offroading.net/forum/viewtopic.php?f=43&t=3288 this excellent link. I only have 2 banks of 6 fuses, but reckon the 4 spare will get used up.

In the meantime - going to test the fuse holder, by taking the wires out of line, and putting into a single blade holder I will take off my Disco 200tdi breaker, to see if it the fuse holder that is the fault. (The above cure is long overdue - and no work at mo seems good time to do it).

If this is not the problem it could be the earth - however the Haynes manual is a bit vague (tch) as usual in their wiring circuit to where the earth on the heater ciruit actually is - does any one know ?

[Peter]

2nd question. Does the fuse just blow the fan or does it control the Rheaostat too ?

I.e. if I Do Ruu's conversion will it negate the need for the above issue ?

[western]

only protects the motor AFAIK, the fuseclips maybe touching on the back of the fusebox, my 110 has glass fuses & the slightly longer Halfords fuses do fit, Can your blower motor turn frely if you move it by hand, it maybe the motor is siezing up.

[pete3000]

one problem I ran into with my ex mil 110 with glass fuses. On the fuse cover plate the fuses are marked for holding current.

The fuses you buy from motor factors are trip limit. Someone on the emlra forum informed me of this. May be different on yours though.

It made perfect sense, as my sidelight fuses marked 2.5A kept blowing with sankey trailer connected after a couple of minutes.

I had fitted 2.5A glass fuses. They should have been 5A.

Deduce from current draw of circuit 2x side lights 10w + 5w no. plate lamp =25w. 20W/12v (just over 2A) connect trailer and add 20W= 45w / 12 = 3.5 A ish.

Can you measure the current draw on second speed with good fuse? and compare with someone else?

You shouldn't be tempted to put bigger fuses than the wiring can cope with, it will only end in tears.

[Peter]

Thanks for the replies. I have taken the wires from the heater fuse, and put a blade fuse holder in line, with a 10amp fuse. Made it long enough so can change it without having to take the fuse cover off, and the CB I have mounted in front. Anyway, the wires and fuse holder do get warm when on speed 2. But is okay on Speed 1.

So assume there is resistance in the circuit.

It would make sense that it is the fan unit itself. Will dismantle this tomorrow and see if it is possible to turn by hand. I take it, its a sealed bearing and cannot be oiled/greased ?

[trt1617]

had the same happen to mine for ages and you can keep cleaning the motor out and freeing it off but it will still keep blowing fuses after a while and mine went on for about six months or so until it just stopped and needed a new motor

they are cheap enough and easy to do if it happened again i wouldnt bother trying to clean it just put another one in

[western]

Correct it's a sealed for life motor, have a look at the resistor unit to, under the bit where the wires go in to the heater unit.

[Peter]

Currently thinking of taking fan out, and using a Bilge pump (see ruu's post) connected to the resistor, as reckon it will control the speed. Be interesting to see if it works as would save a lot of dosh. Apparently the amp draw is 2.7amps, way below the 10amp the Defender fan draws on full speed.