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Heater Fault

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Would really appreciate any help or suggestions with this as I really don't have the first idea when it comes to electrical problems.

My 90 originally had air-con and therefore has unfamiliar heater controls when compared to other 90s, the fan has 3 speeds and the third (fastest) has never worked. With the wet/cold weather recently the windows seem to be constantly covered in condensation. The V8 produces plenty of heat so it would be really, really good to have a bit more 'blow' to get that heat into the vehicle and onto the windows!

I've done a little research and have come to the conclusion that it could be down to a failed resistor? Now, does anyone know A)where the hell this lives? And B) can it be changed and if so how? or C)anything else I can do? - I plan to check and seal any leaks from the blower motor through to the vents but obviously if I had top speed working on the motor, that would improve things hugely.

Any help/advice would be great as the condensation is driving me crazy!!

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assuming you have the underdash air con fitted, the resistor is item 5 in http://www.numcat.ru/landrover/p/31/52937/ might be a air con duct remove to access the motor/resistor.

if it's the vertical in dash unit, resistor maybe in the control panel in http://www.numcat.ru/landrover/p/31/52944/ or within the evaporater unit http://www.numcat.ru/landrover/p/31/52939/

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Many thanks for your input, gives me something else to work with in my research! Looking at your links, it would appear I have the vertical dash unit. I take it there was two air con systems fitted to early 90s/110s - what do these names mean - 'underdash' and 'vertical'?

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Yes I definitely have the 'vertical' variety!

I guess the resistor is in that box of tricks (item 4 in diagram) and I wouldn't want or know how to take that apart. Would a new one still be available I wonder? Even if it were it looks like it'd be over £200.

So, fixing it or replacing it do not appear to be options. So does anyone know if I could fit the Rover 100 fan speed control and ballast resister - I understand it is a popular mod with 90s/110s with the convential heating/ventilation?


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looking at the air con wiring diagrams/section in my workshop manual it shows the resistor block with 4 wires




yellow/black trace

the yellow/black goes to the relay, the other 3 to the control switch unit.

for left hand drive vehicles it says to remove the resistor block, open bonnet, detach the blower motor wiring connector, remove the self tapping screw & lift out the resistor block,

for right hand drive, open bonnet, on the left [vehicles left] of the engine bay, the resistor block has 2 hex head bolts securing it to the left wing upper inner edge approx in line with the wing top air intake cover, remove the bolts/disconnect the plug & lift out the resistor block.

item 1 in http://www.numcat.ru/landrover/p/31/52815/ is the resistor for RHD vehicles.

no picture of the actual resistor but here for just over 11 quid http://www.brit-car.co.uk/product.php?xProd=140732 or here for a bit less cash http://www.lrseries.com/shop/product/listing/2348/AEU1747-RESISTOR.html?search=AEU1747&page=1

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Western you are a legend! Really appraeciate you taking the time to look this up - top bloke! Many, many thanks!

Looks pretty straight forward, and inexpensive too! What is the likelyhood the reason speed 3 isn't working being a failed resistor? Do you know if there are any tests I can do to confirm it's the resistor that's failed?

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in the air con fault diagnosis chart in my workshop manual, it says

blower motor with less than 3 speeds, inspect resistor block, -- resistor block defective = replace

or resistor block OK -- inspect blower switch & replace switch if defective,

so yes a duff resistor will knock out 1 or more fan speeds.

manual doesn't give any test for dead resistor, just the info above, glad it's all been useful.

hth :i-m_so_happy:

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