Heater fan - best way to diagnose?

[RaZz0R]

Hi All,

So I have been reading up as much as I can and also searching here.

Before I go ripping the dash apart and trying to get in to the scuttle pan I wondered how could I diagnose the following;

Issue - Heater fan not working. No fans work unless aircon switch is on and the fan switch on high;

Could be either the blower itself or the resistor pack?

I also came across this;

You cannot buy the resistors anymore, only aftermarket ones are available. The aftermarket ones are just made from resistors that you can buy in you local electronics store, so you can make them yourself. You need a 2.0 ohm, 1.5 ohm, and 0.5 ohm resistors. No real need to pull your dash apart as you only need to unplug the old resistor wiring under your dash and plug in your made one.

So with that in mind - I wonder how I could test to figure out if its the resistor pack or the blower; and if its the resistor pack, has anyone done the above where they have made their own?

Thanks in advance!

[alien]

Watching with interest.
My resistor pack has failed and the fan only blows on the high setting.

[roverv8]

what yr is it?
I recently picked up a 91 RRC, the fan works on all speeds with AC mode but I have no fan at all when switched to heater. even on high
I think the heater fan is burnt out...

[RaZz0R]

what yr is it?
I recently picked up a 91 RRC, the fan works on all speeds with AC mode but I have no fan at all when switched to heater. even on high
I think the heater fan is burnt out...

Its a 94 - I too have a 91 still parked in my carport so I can rip in to that for parts.

But I am keen to know more about not having to do that **** :)

[DieselLSE]

Before doing any of the above checks, make sure that either or both of the three-position switches are not broken or that the connectors have not come adrift. The switches are notoriously flimsy and expensive to replace, but at least they are relatively easy to access.
Be careful removing the connectors as the terminals are riveted on and can easily fall off! The switches are sort of repairable, but being so flimsy makes it difficult.

https://www.aulro.com/afvb/images/imported/2017/07/365.jpg

[RaZz0R]

Before doing any of the above checks, make sure that either or both of the three-position switches are not broken or that the connectors have not come adrift. The switches are notoriously flimsy and expensive to replace, but at least they are relatively easy to access.
Be careful removing the connectors as the terminals are riveted on and can easily fall off! The switches are sort of repairable, but being so flimsy makes it difficult.

https://www.aulro.com/afvb/images/imported/2017/07/365.jpg

Awesome tip! I'll be doing this tomorrow for the first bit of work for the weekend. I'll report what I find :)

Cheers!! [bigrolf][bigrolf]

[Davo]

I found the resistors on a '92 under the decker panel, so you might be able to see them through the intake vents.

[RaZz0R]

Awesome tip! I'll be doing this tomorrow for the first bit of work for the weekend. I'll report what I find :)

Cheers!! [bigrolf][bigrolf]

Well - I found that the switch is fine - funny enough we found with all settings set to heater - that the aircon fans turned on but not very fast... and very quite as well.
But no heater blower thats for sure.

So next up will be the resistor pack. Fun times!

[DieselLSE]

Do you have a wiring diagram? PDF attached FYI126114.

[RaZz0R]

Do you have a wiring diagram? PDF attached FYI126114.

Thats for that. so yeah I can see the two step resistor there that comes on with the heater fans.

As much reading as I have done - I am lucky in one way that I have a 91 RRC sitting here still with these parts working.

BUT - thats going very soon to a mate that owns AMV, he going to rip out the 4.6 V8 for him self while i get the transfer case to keep as a spare.
SO I need to rip all parts out that I might want or need before it goes. So Going to rip out the heater box and the resistor pack so I can see what I am dealing with.

I also found this on rover parts that shows the wiring for the resistor pack and how to splice in their one... makes ya wonder :)
Splicing In New Resistor On Range Rover Classic (http://www.roverparts.com/Instructions/RRC_A-C_Heater_Blower_Resistor_PRC8010_4.cfm)

I did also come across a thread where some tech heads were talking about replacing the resistor pack with new technology using fetts? \ solid state setup.
However this is getting in to an area of electronics that past my understanding :)

[DieselLSE]

I did also come across a thread where some tech heads were talking about replacing the resistor pack with new technology using fetts? \ solid state setup.
However this is getting in to an area of electronics that past my understanding :)

Solid state would be the way to go, but if you can get the resistors from another vehicle then do so. They're easy to access, so you can always change them later if you need to. Simply remove the aircon filters. If the single strip of metal behind the filter is still attached, simply drill out the rivets and remove it, then rivet it back on again afterwards. Removing it aids access, but it is needed to stop the filter falling inwards. BTW, also change over the filters. They are still available and relatively cheap. I have a spare set if you need them. MXC3910G
https://www.aulro.com/afvb/images/imported/2017/07/436.jpg

[Mercguy]

I'm not sure if you have electronic skills or not, but you can buy PWM speed controllers with soft start etc on ebay. there's only 4 wires to connect - two for power feed and two to the motor. The potentiometer is a rotary type, which is easily exchanged for a slider type, to fit into the same spot as the factory 3 speed switch. Most are based on a TL494CN PWM switching regulator and a pair of N channel mosfet's

To my mind it's a far more sensible way to drive the motor, because the 3 speeds aren't enough - full bore is too much and sometimes 2 is not enough. and one doesn't even blow air half the time - I think fresh air overrides it.

Anyway, that's just an option

You'll find them on ebay everywhere or you can buy a 10A or 20A kit from jaycar, which are a bit pricier - but don't be fooled by price. often the components in ebay stuff are just junk. So be aware of what you're buying.

Here's an example: uniquegoods 6V 12V 24V DC 10A PWM DC Motor Speed Controller Adjustable Variable (http://www.ebay.com/itm/uniquegoods-6V-12V-24V-DC-10A-PWM-DC-Motor-Speed-Controller-Adjustable-Variable-/222277549425?_trksid=p2349526.m2548.l4275)

Jaycar 10A version : 10A 12VDC Motor Speed Controller Kit | Jaycar Electronics (https://www.jaycar.com.au/10a-12vdc-motor-speed-controller-kit/p/KC5225) - nb you can add another fet and run 20A for example:
126135126136
20A HD version 12/24VDC 20A Motor Speed Controller Kit | Jaycar Electronics (https://www.jaycar.com.au/12-24vdc-20a-motor-speed-controller-kit/p/KC5502)


Anyway, it's all easy to fab something like this up if you have a working knowledge of circuits. use a 10K sliding linear pot and that should fit into the existing space - or near enought to -
RA4520F-10-20D1-B5K Alpha (Taiwan) | Mouser Australia (http://au.mouser.com/ProductDetail/Alpha-Taiwan/RA4520F-10-20D1-B5K/?qs=Oo40KB9lBTlyW2j33yNnZw%3d%3d)

[RaZz0R]

Well I managed to get in to the resistor area thanks to my girl - she got it all undone... but what we found wasn't what I had expected.

126206

So whats the deal with this? And of course the corrosion is a concern. Last time I used \ test the fans in my greenie they worked. So I guess this thing will?

I also pulled out the blower today just in case the new cars one is DOA - pitta of a job that - I would hate to put it back - so if its DOA - I am getting AMV to do it lol or LRA.
lol [biggrin]

126205

[RaZz0R]

OK, Electronic skills for myself go like this;

I can solder well and know a good join
I understand how some of those components work
I understand the idea of the potentiometer

The jaycar one - 30 buck no problem, as long as I have a guide to build it - no worries. The switch - same deal...

So will the 10A one do the job and if I go build it... could you or someone you know assist in knowing which 4 wires to connect to it and the switch? Thats about the only missing part of the puzzle for me.

Think I got enough of an understanding to do it? :lol2::whistling::TakeABow:
When I went looking for the resistor pack - I was expecting a circuit like pictured below, but perhaps older parts. This round thing with wires connected is very old school to me :)


I'm not sure if you have electronic skills or not, but you can buy PWM speed controllers with soft start etc on ebay. there's only 4 wires to connect - two for power feed and two to the motor. The potentiometer is a rotary type, which is easily exchanged for a slider type, to fit into the same spot as the factory 3 speed switch. Most are based on a TL494CN PWM switching regulator and a pair of N channel mosfet's

To my mind it's a far more sensible way to drive the motor, because the 3 speeds aren't enough - full bore is too much and sometimes 2 is not enough. and one doesn't even blow air half the time - I think fresh air overrides it.

Anyway, that's just an option

You'll find them on ebay everywhere or you can buy a 10A or 20A kit from jaycar, which are a bit pricier - but don't be fooled by price. often the components in ebay stuff are just junk. So be aware of what you're buying.

Here's an example: uniquegoods 6V 12V 24V DC 10A PWM DC Motor Speed Controller Adjustable Variable (http://www.ebay.com/itm/uniquegoods-6V-12V-24V-DC-10A-PWM-DC-Motor-Speed-Controller-Adjustable-Variable-/222277549425?_trksid=p2349526.m2548.l4275)

Jaycar 10A version : 10A 12VDC Motor Speed Controller Kit | Jaycar Electronics (https://www.jaycar.com.au/10a-12vdc-motor-speed-controller-kit/p/KC5225) - nb you can add another fet and run 20A for example:
126135126136
20A HD version 12/24VDC 20A Motor Speed Controller Kit | Jaycar Electronics (https://www.jaycar.com.au/12-24vdc-20a-motor-speed-controller-kit/p/KC5502)


Anyway, it's all easy to fab something like this up if you have a working knowledge of circuits. use a 10K sliding linear pot and that should fit into the existing space - or near enought to -
RA4520F-10-20D1-B5K Alpha (Taiwan) | Mouser Australia (http://au.mouser.com/ProductDetail/Alpha-Taiwan/RA4520F-10-20D1-B5K/?qs=Oo40KB9lBTlyW2j33yNnZw%3d%3d)

[Mercguy]

OK, Electronic skills for myself go like this;

I can solder well and know a good join
I understand how some of those components work
I understand the idea of the potentiometer

The jaycar one - 30 buck no problem, as long as I have a guide to build it - no worries. The switch - same deal...

So will the 10A one do the job and if I go build it... could you or someone you know assist in knowing which 4 wires to connect to it and the switch? Thats about the only missing part of the puzzle for me.

Think I got enough of an understanding to do it? :lol2::whistling::TakeABow:
When I went looking for the resistor pack - I was expecting a circuit like pictured below, but perhaps older parts. This round thing with wires connected is very old school to me :)


I sent you a PM. [thumbsupbig]

[RaZz0R]

Well I pulled out the resistor for the heater from the green one - no change - still dead and no heater. Damn it!

After pulling the heater form the greenie I have decided to have it professionally done - and then I'll change the resistor over to a more up to date design :)

[BigJon]

From memory my 88 runs two different fans. One in the centre of the dash does the heater and fresh air, one in the passenger footwell does A/C air.

[RaZz0R]

From memory my 88 runs two different fans. One in the centre of the dash does the heater and fresh air, one in the passenger footwell does A/C air.

Thats right - two totally different systems - Aircon fans work - but seem to be an issue with the compressor or some such - so may as well get that sorted at the same time.

[Meccles]

I'm fitting a complete new Vintage Air HVAC system all early original smiths heater boxs I could find were pretty shot and A/c was older style under dash units with various bits of moulding/ trunking. Will let you know how well it works when we gas it up. Relatively cheap I paid about $600 for unit delivered. It is different dimensions of course smaller in height and thinner but a bit wider. It will require a new center cover panel to be fabricated. But looking at numbers to repair yours if there was significant change/ repair required, this gives new modern option.

[Mercguy]

HVAC is one of my pet hates. like chiller plants, ducting, dampers and air balancing.

in a car, the system is so small and simple, it really doesn't need to be made more complicated.
The biggest issues with older systems is they don't respond in a linear fashion. it's either bloody freezing or too freakin hot.
with blended AC, having the heat and cool run together means it's less efficient overall, but it is more accurate.
modern AC in some cars has some very expensive and clever control, variable flow fluid pumps, multiple level thermocouple sensing...

I like fresh air.
and heated seats.
[biggrin]

Nearly every automotive HVAC system I've had the displeasure to 'fix' has required a monumental effort to not only repair, but to actually improve, given the space constraints under the dashboard.

the RRC is absolutely massive in terms of free space, and to my mind has endless freedoms. a Vintage air unit sounds like a good alternative - but do they make RHD (passenger side mount) units? the Gen 2 and Gen 4 units that I have seen are setup for mounting on the drivers side (US pass. side)

have you got any pics of your unit model? I'm curious.

[Meccles]

I've got a Gen 11 unit mounted in centre of firewall. Pics later. The only thing being designed for LHD the heater hose and evaporator outlets are on right. I just got some 180degree fittings they are cheap and available to route a/c to left. The heater hose unit comes with proper isolation valve more than enough room to fit this behind unit and used normal heater hose no issue at all. The defrost outlets are in correct place- towards firewall and a/c - heat outlets - also looking good. All modern stepper motors etc etc. and light way lighter than original units.

[RaZz0R]

I've got a Gen 11 unit mounted in centre of firewall. Pics later. The only thing being designed for LHD the heater hose and evaporator outlets are on right. I just got some 180degree fittings they are cheap and available to route a/c to left. The heater hose unit comes with proper isolation valve more than enough room to fit this behind unit and used normal heater hose no issue at all. The defrost outlets are in correct place- towards firewall and a/c - heat outlets - also looking good. All modern stepper motors etc etc. and light way lighter than original units.

Yes please pics :)
Since I am going to replace it - I would love to update it in some way :)

[Meccles]

Here's what I have done. Note I will be replacing the flat bar across top of dash with angle the flat bar flexes too much. I will post a few replies cause I took a few photos
127080
127081
This is gap between unit and firewall and where I ran hoses
127082
127083
This is heater water control valve fits nicely near underneath dash
127084

[Meccles]

This shows demist outlets there are two but will T them off to use original outlets on dash
127085
This shows 4x a/c outlets will hook these up to 4 x eyeball outlets that exist already in dash
127089
This is 180 degree fittings for a/c hose
127091
This is heater hose plumbing
127092
This is clearance under unit to transmission tunnel
127093

[Meccles]

This shows where I ran engine bay hoses compressor is on passenger side of engine I used bulkhead fittings. Cable clamps still to come.
127097
This is control unit I chose in keeping with LR style
127099
You get very good instructions with the unit. It does not come with a/c hoses or control unit as you have to chose the style of what you want. It does come with heater valve all wiring all duct hoses and mounting brackets
127102

[Davo]

Bloody hell Meccles, that's got to be the best solution I've seen to the problem of the original heater-and-aircon mess. I rebuilt my heater and had a horrible time shoehorning the thing back in, a job I'll never forget. I don't even have it connected up here, I just wanted it rebuilt for later! I also reinstalled the original aircon but then put a new unit up in the cargo barrier, so the original has to come out one day. But who in their right mind wants to fiddle with that awful dash if they don't have to?

[350RRC]

That's bloody impressive Meccles!

I rebuilt the original heater in my POS when the 81 body went on. Rebuild was really just new felt on the control flaps and lubing the bronze bushes in the fan motor.

This was done with the whole dash out, like you have done. I prefer the early ones without the gauges up top so the 74 one was going in, in place of the 81. It's really the only way get the heater unit out to repair / replace.

Taking the whole dash out seems like a daunting prospect before you do it, but I can't remember any big hassles.

Cleaning up any electrical issues, etc while the whole dash is out is also really simple.

cheers, DL

[Mercguy]

Cleaning up any electrical issues, etc while the whole dash is out is also really simple.
cheers, DL

Amen to that.

Not to mention cleaning up all the 22+ y.o. dustbunnies, washing out the ac ducting, clearing drains, checking for bulkhead rust...

[Meccles]

I've just got to hope that the cunning plan works[emoji51]it should - but the proof will be in pudding. Next challenge is fitting biggest condenser I can. Will update all in 77 thread with how it goes

[Mercguy]

I've just got to hope that the cunning plan works[emoji51]it should - but the proof will be in pudding. Next challenge is fitting biggest condenser I can. Will update all in 77 thread with how it goes

early RRC
127138

Late RRC

127139

[Meccles]

Interesting that about biggest vintage air condenser you can buy other than their "monster" condenser is 24"x14"x0.830". So 609mm x 356mm x 21mm. They claim superior design etc and are quite reasonably priced. I think that's way I'll go

[RaZz0R]

This shows where I ran engine bay hoses compressor is on passenger side of engine I used bulkhead fittings. Cable clamps still to come.
127097
This is control unit I chose in keeping with LR style
127099
You get very good instructions with the unit. It does not come with a/c hoses or control unit as you have to chose the style of what you want. It does come with heater valve all wiring all duct hoses and mounting brackets
127102

Thanks a million for this! I'll show it to Greg at AMV and see if he is willing instead of trying to rebuild the ones I have. [bigrolf]:bat:

[Meccles]

They are available in Australia Retrospares carry them plus other stockists. Price up a bit now we have Pacific Peso's but still not too outlandish. If you only need the evaporator unit plus controls 1k will do it. Leaves quite a chunk for fitting up if you were budgeting 2-3k.

[Hugh A Rea]

OK, Electronic skills for myself go like this;

I can solder well and know a good join
I understand how some of those components work
I understand the idea of the potentiometer

The jaycar one - 30 buck no problem, as long as I have a guide to build it - no worries. The switch - same deal...

So will the 10A one do the job and if I go build it... could you or someone you know assist in knowing which 4 wires to connect to it and the switch? Thats about the only missing part of the puzzle for me.

Think I got enough of an understanding to do it? :lol2::whistling::TakeABow:
When I went looking for the resistor pack - I was expecting a circuit like pictured below, but perhaps older parts. This round thing with wires connected is very old school to me :)

Just curious if someone has done this and is it a successful modification?