Help! Interior Fan Problem

Help! Please!!!

I have a 52' plate Disco TD5 which has a digital dual zone climate control.
Whilst the display etc works fine the FAN only works on the HIGHEST blower setting. (The fan has 1-5 blower settings and it only works on setting 5 - which blows your head off!)

This is based on using the 'manual over-ride' to go though the fan blower levels. (When on 'Auto' there is no real activity as I guess it's also generally trying to use level settings 1-4 of the blower for temp regulation)

Without taking it to the stealer-dealer, does anmyone know what what can I check? Is it likely to be the fan or the heater unit (ie display unit)?

I guess the fan either works, or doesn't and clearly it works well on setting 5. The air-c0n works fine also but I only seem to have 'super-freeze on leve; 5 fan or nothign in which case I bake in the cabin...

I would be REALLY GRATEFUL for any advice!!!!
Thanks!!!

Emo

I have a similar issue on my 300 Tdi (pre digital display for heater control). Of the four settings for the fan, it will only work on the latter two (number 3 and 4). When moving the slider from 0 to 1 or 2 a faint click can be heared near the glovebox so I'm assuming switchgear is fine and it must be something to do with the fan, probably the same for you as well I should imagine.

Interesting... but I suspect the fan is ok (I could well be wrong as electronics is not my bag) but if the fan works, then it works. It will typically have a switch for the fan so it is ON or OFF. The variance of the fan speed is more likely related to the 'feed' such as the amps or voltage supplied to it to vary the speed.. As such, i suspect the unit as this is likely to control the feed??? (i am guessing here!!!)

Especially as you have an 'analogue' slider unit, there could be a problem with the contacts on some of the settings?

I am temped to try and source a new display unit, but if this isn't the problem i am throwing money blindly at a problem I don't fully understand... Same for you I guess...

We need some know how here clearly... Anyone have any intel?

Well, I bought a replacement panel with the switch and it made no difference, settings 3 and 4 were still the only ones which worked. Fan is the only thing I have left to replace.

Oh, well that is interesting... Are you mplanning to replace the fan then? Would you be willing to let me know if this fixes the problem for you if so... Or, if you are still hesitant to replace the fan, do you think it could be a simple resistor or some 'in-line' type device???

I have 2 main problems:
1/. I don't know all the main components that effect the fan
2/. I don't know how to diagnose the root cause.

My other problem is that i am a bit thick!

The fan is powered from a relay in the passenger compartment fuse box. If this relay is bad, you will have no fan at any speed.

On the other terminal on the fan is the negative side. There are two things attached to it. One is another relay. When this is switched on, you have a clean path to ground and the fan turns on high. The other thing attached to that terminal is a transistorized speed control that connects to ground at various resistances to give you different speeds.

Sounds like that's what you need to replace.

Correct-side drive picture (it's C858 in this one):

I was intending to replace the fan as a friend told me some cars have a controller on the fan, sort of a stepper that ups the speed depending what is selected on the controller, apparently not all cars have a simple fan motor with a positive and negative but my Tdi decided to play silly buggers and develop a ticking noise from the engine bay so will be trying to sort that before I sort the fan I'm afraid.
I have a haynes manual I'll have a look into the wiring to the fan if that helps to determine if there is indeed more than 2 wires to the fan motor and what else is involved.

Cave Johnson said:

I have a haynes manual I'll have a look into the wiring to the fan if that helps to determine if there is indeed more than 2 wires to the fan motor and what else is involved.

Click to expand...

It does, as you can see below. Part G102 ("resistor pack") is what I was talking about replacing (although I thought it was transistorized before pulling this diagram - I mush have gotten bad information on that):



You can get the full diagrams and shop manual here. It will have a lot more detail than your Haynes manual.

Good luck on the tick.

The various fan speeds are controlled by the speed control on the dash which feeds a block resistor on the fan plastic frame and then onto the fan itself.

Your problem is most likely the resistor block.

Motronic said:

The fan is powered from a relay in the passenger compartment fuse box. If this relay is bad, you will have no fan at any speed.

On the other terminal on the fan is the negative side. There are two things attached to it. One is another relay. When this is switched on, you have a clean path to ground and the fan turns on high. The other thing attached to that terminal is a transistorized speed control that connects to ground at various resistances to give you different speeds.

Sounds like that's what you need to replace.

Correct-side drive picture (it's C858 in this one):

Click to expand...

This information is very helpfu! Thank you! I will start with that resistor! Do you know where I can get a LR recognised part number (for C858) to order it?

Also, any idea how I access this HVAC/Fan unit? Is it an IP out operation? Or removal of glovebox or centre console etc?

Thanks again!!!!!!!!!!!!

thebiglad said:

The various fan speeds are controlled by the speed control on the dash which feeds a block resistor on the fan plastic frame and then onto the fan itself.

Your problem is most likely the resistor block.

Click to expand...

Equally, thank you very much for this info!!
It provides a positive starting point for me and will HOPEFULLY solve the issue of fan settings 1-4 not doing anything! ...I just need to fisure out how the hell to get to the fan unit!! :doh:

Cheers!

Have a read of this

http://www.landyzone.co.uk/lz/f8/blower-heater-cheap-fix-128192.html

A new resistor pack will cost you £100

The part you need if you can get your hands on it will cost you no more than a tenner plus a bit of soldering

How to remove

Plug 4 is into the resistor pack which can be removed without removing the blower, with a bit of fiddling

biggeeeee said:

How to remove

Plug 4 is into the resistor pack which can be removed without removing the blower, with a bit of fiddling

Click to expand...

You guys are legends! This is so helpful, thank you very much!
I couldn't quite determine which 'cheap' resistor to but and where from though?

Thanks for the info on how to access the fan unit also!
Cheers

The scheme with the resistor pack is for manual system to controll the heater blower... not for climatronic with digital controll....the digital A/C fan is controlled by a POWER TRANSISTOR, i'm quite sure that's your problem... see this http://www.landyzone.co.uk/lz/f8/heater-fan-full-only-111579.html and even deeper this http://www.landyzone.co.uk/lz/f8/51-plate-discovery-blower-problem-105444-2.html

If it'll turn out that this is the problem then here is the cheap fix for it : quoting myself from D2boysclub " if u have problems with the aircon blower speed controll the most obvious fault is the power transistor(here's a pic http://www.lrseries.com/shop/product/li ... tor&page=1 , u dont have to spend that much, u just have to get hold of a Toshiba 2SD1460, or similar(MJ11016 - i used one of this and it works, MJ11014, BDX69B, etc.The transistor is screwed to the aluminium cooler but the connections are all potted in epoxy so it would take a little work with a dremel tool to get to the connections...... cant be more than 10 quid i think. "

sierrafery said:

The scheme with the resistor pack is for manual system to controll the heater blower... not for climatronic with digital controll....the digital A/C fan is controlled by a POWER TRANSISTOR, i'm quite sure that's your problem... see this http://www.landyzone.co.uk/lz/f8/heater-fan-full-only-111579.html and even deeper this http://www.landyzone.co.uk/lz/f8/51-plate-discovery-blower-problem-105444-2.html

If it'll turn out that this is the problem then here is the cheap fix for it : quoting myself from D2boysclub " if u have problems with the aircon blower speed controll the most obvious fault is the power transistor(here's a pic http://www.lrseries.com/shop/product/li ... tor&page=1 , u dont have to spend that much, u just have to get hold of a Toshiba 2SD1460, or similar(MJ11016 - i used one of this and it works, MJ11014, BDX69B, etc.The transistor is screwed to the aluminium cooler but the connections are all potted in epoxy so it would take a little work with a dremel tool to get to the connections...... cant be more than 10 quid i think. "

Click to expand...

Thanks! Any idea how I acess the fan unit? Do I approach from under the dash, remove the glovebox or remove the whole centre unit? Or, do I access from the engine bay?

Thanks... No more questions I promise! ;-)

To remove the glovebox must be enough

Motronic said:

It does, as you can see below. Part G102 ("resistor pack") is what I was talking about replacing (although I thought it was transistorized before pulling this diagram - I mush have gotten bad information on that):

You can get the full diagrams and shop manual here. It will have a lot more detail than your Haynes manual.

Good luck on the tick.

Click to expand...

Thanks very much!
I'm certainly glad I joined here, you certainly know your stuff

Just want to pop in and say 'resistor'

Classic case!

I must say again that we are talking about a digitaly controlled A/C system here(if i understood well from the first post)...it has noting to do with resistor/resistor pack