Help please 200tdi heater munching 10amp fuses

Hi all, having problems with my heater. The minute you turn it on it blows the fuse. Hoping you guys can help me diagnose the problem. The heater box was given a bloody good clean when I replaced the heater matrix a few months back

I have 11.86v at the 2x wires that go to the relay/fan

Resistance test shows 1

I have tried unplugging the relay/fan motor connector and that does stop the fuse from blowing

but

I have also tried pulling -/+ wires behind the fan control switch and bypassing the switch with a test lead. I expected either the fan would run indicating a fault with the switch itself or a blown fuse...I got neither?...that confused me

Re assembled and blows every time I turn the switch on

It has only worked on the flat out setting since being in my ownership...not sure if that was a symptom

help gratefully received as it’s getting pretty chilly!

Update

Have had another go at the bypass of the switch and this time the fans came into life without blowing the fuse. (Must have had a poor connection or bad test wire previously)

So now

Disconnect the relay/motor wires and the fuse doesn’t blow when switched on (No Fan obviously)

Bypass the switch and the fan works when connected ((smoke from test wire))

put it all together and fuse blows right away

So what is the fault?

For further info the By Pass of the fan control switch is successful when joining black with 2nd stage green purple wire but not when joining with black with 1st stage green yellow?

The fan speed is 'controlled' by a resistor which is located in the air-flow chamber just in front of the fan. Three wires go to it. 1 comes straigh out again to the motor, the other 2 pass through the resistor. Effectively the resistor reduces the voltage so that the fan runs slower. In high speed mode the resistor is bypassed. The plate (holding the resistor) is riveted in (see pic).

If the resistor is shorting to ground it will pop the fuse.
Whip it out and have a look-see. If you have a digital multi-meter you should be able to measure the resistance ...

I put a lower resistance in mine which makes the fan run faster when in slow mode than standard.

See here .... https://www.landyzone.co.uk/land-rover/heater-resistor.307414/

Yes, I would say it's a dodgy resistor. It has been dodgy since you bought it if the slower speeds never worked, that stage of the resistor went open circuit. Now it sounds like the resistor is shorting to earth causing closed circuit hence blown fuse. You could just bypass the resistor and have full power when switched on.

Col

Bet you the fan is toast they are carp, the bearings (oiltite) seize on the shaft then they spin in the black housing, all the time the fan is getting slower/weaker, the fact the test wire was smoking tells you all you need to know, not cheap either.
You can sort of take them apart clean/oil but it does not last.

eBay is your friend .... 164580176140

If you drop an eMail to Synetiq they will get you one, a great company and always sort out any problems and supply working kit.

This is what the resistor looks like.
Its attached to a small bracket with the screw and the fan sucks air through it ...

miktdish said:

This is what the resistor looks like.
Its attached to a small bracket with the screw and the fan sucks air through it ...

View attachment 226356 View attachment 226358

Click to expand...

Thank you for taking the time to respond and in such great detail. I have ordered a relay kit via the bay with the modified resistor to speed up the slow setting hopefully this will rectify the gremlins and have the cabin fairies ( my lasses) all nice and toastie again.

Should I be worried about the motor?...it does fire up and run when bypassed. Short delay, some noise of fluid in motion in the general direction of the heater box followed by fans blowing so assumed motor was fine ?

Fluid in motion ? Heater intake drain clear ?

TheCornishman said:

Thank you for taking the time to respond and in such great detail. I have ordered a relay kit via the bay with the modified resistor to speed up the slow setting hopefully this will rectify the gremlins and have the cabin fairies ( my lasses) all nice and toastie again.

Should I be worried about the motor?...it does fire up and run when bypassed. Short delay, some noise of fluid in motion in the general direction of the heater box followed by fans blowing so assumed motor was fine ?

Click to expand...

Not sure if the 200Tdi is the same as the 300Tdi, but the air inlet pipe from the top of the wing has a rubber 'bird's mouth' valve at the bottom of it about 20+cm from the heater box. Check this isn't full of carp by squeezing it. They block up and the air inlet pipe then fills with water, your fan then acts like a water wheel swooshing the collected water around. Have you had a lot of rain recently?

tottot said:

Fluid in motion ? Heater intake drain clear ?

Click to expand...

I always use too many words and so take too long to reply

lynall said:

Bet you the fan is toast they are carp, the bearings (oiltite) seize on the shaft then they spin in the black housing, all the time the fan is getting slower/weaker, the fact the test wire was smoking tells you all you need to know, not cheap either.
You can sort of take them apart clean/oil but it does not last.[

Click to expand...

tottot said:

Fluid in motion ? Heater intake drain clear ?

Click to expand...

Havent checked but it certainly was when reassembled after matrix replacement..I will check again. Can I ask why that would make a noise when the heaters fire up?

Hum...certainly have had a lot of rain the last few days but it packed up last week?...will check though

Think I will pull the heater box and have a good nose about

TheCornishman said:

<snip>
Think I will pull the heater box and have a good nose about

Click to expand...

One little sentence, so much work

miktdish said:

One little sentence, so much work

Click to expand...

Especially them two bottom bolts!

TheCornishman said:

Havent checked but it certainly was when reassembled after matrix replacement..I will check again. Can I ask why that would make a noise when the heaters fire up?

Click to expand...

The fan is in the bottom of the box which is the lowest point for water to pool. The fan the paddles the water around. This is often accompanied by a lot of condensation on the screen. You might not have noticed this if the fuse has been blowing. If you cleared the valve recently it's probably ok.

TheCornishman said:

Hum...certainly have had a lot of rain the last few days but it packed up last week?...will check though

Think I will pull the heater box and have a good nose about

Click to expand...

Before removing the heater box completely, remove the plastic pipe from the intake, and try to spin the fan by hand. If it feels smooth and doesn’t make a noise, then it’s relatively safe to assume it’s free and good. If you can do the resistor mod while it’s all fitted, that’s how I would go about it.

mick 1986 said:

Before removing the heater box completely, remove the plastic pipe from the intake, and try to spin the fan by hand. If it feels smooth and doesn’t make a noise, then it’s relatively safe to assume it’s free and good. If you can do the resistor mod while it’s all fitted, that’s how I would go about it.

Click to expand...

Thanks gents for all the input...

Went for a family drive on New Year’s Day...it was Baltic. To my surprise and delight when I tried the heater the bloody thing fired up.

The Mrs was most grateful for the 200’s decision to oblige with some warmth...let’s just say they don’t have the best of relationships...

Anyway...know convinced it’s a water ingress problem. New Year’s Day was cold but it was dry as was the day before.

So whilst having a bash at sorting my handbrakes laughable efforts, & replace the bloody useless hazard switch for a Carlinh unit today I plan to check out what’s going on.

MOT on Wednesday...wish me luck

So mixed bag today...

Handbrake adjusted and now would hold like Spider-Man’s underwear...cable is adjusted right out to max so will need replacing but should be fine for MOT

Sure enough my intermittent heater problem was indeed this little devil. It was blocked completely and holding around 2” of water in front of the motor. All working fine now and hopefully no lasting damage to the motor. I have the upgraded relay kit to fit and think I will put a snow cowl on to prevent this happening again. Q?...any reason not to simply toss the duck billed drain grommit in the bin?...

Hazards...

the saga continues but after multiple switches giving me mixed results and constant grief I decided to swap out for a carling unit. Wired it in today but still have no hazards or indicators. Just that blodsy annoying Schmeee sound and the near promise of flickering dash lights. Not blowing indicator fuses anymore but still no dice for MOT