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#21 ·
telferstr said:
Hi there,
Is the failure problem here the Radiator Cooling Fan or the Interior Car Heater Fan? I believe the relay for the Radiator Cooling Fan is incorporated in the Fan Assembly Housing itself. The relay for the Internal Heater/Ventilation Fan is as discribed above, situated in the Fuse Box in the engine bay.
Regards
Telfer
Click to expand...
Yes, all the cooling fan relays are built into the fan unit, relay 5 in the engine compartment fuse panel is the interior heater blower relay. Relay 7 is the compressor clutch relay which may cause problems with the air conditioning.
 
#22 ·
Raykay said:
Yes, all the cooling fan relays are built into the fan unit, relay 5 in the engine compartment fuse panel is the interior heater blower relay. Relay 7 is the compressor clutch relay which may cause problems with the air conditioning.
Click to expand...
Thank you Raykay for confirming that.
Regards
Telfer
 
#23 ·
Fan speeds

Keith enquired about fan speeds and which speed was normal with the a/c on.

I've just tested them using my ACR4.

In fact there as 3 speeds.

Low sounds like normal a/c speed.
Medium is a bit louder
High is hovercraft mode - noticeably loud!

I thought that perhaps the ecu alters the speed depending on vehicle speed because sometimes when slowing down for junctions, the fan note changes as though its speed is altering. But I can't recreate this by letting my speed drop by coasting!

Ron
 
#24 ·
Climate control

hi there,

i have a rover 75 Club and the garage have said that there is a fault in the control box. could anyone tell me where the control box is.

Also i want a workshop manual does anyone know where i could get one.

thanks.

Laurence
 
#25 ·
laurence whelan said:
hi there,

i have a rover 75 Club and the garage have said that there is a fault in the control box. could anyone tell me where the control box is.

Also i want a workshop manual does anyone know where i could get one.
Click to expand...
Welcome "control box" is part of the fan assembly and is, because of the dismantling involved a high cost replacement a couple of us are starting to expolre some alternative options to reduce the repair or ideally the dismantling costs, meanwhile if you do get yours replaced ask for the old one back assuming the fan itself is ok you may well find it is just a relativelyy cheap relay that is at fault

Haynes will be doing a manual soon plus there is a CD based alternative available but we don't discuss those here due to piracy issues
 
#26 ·
Rover_ron said:
Keith enquired about fan speeds and which speed was normal with the a/c on.

I've just tested them using my ACR4.

In fact there as 3 speeds.

Low sounds like normal a/c speed.
Medium is a bit louder
High is hovercraft mode - noticeably loud!
Click to expand...
So you can control them via the ACR4 good
So from what you are saying when we push the AC button we get fan at low, I was assuming it was flat out and as the car was riven it would slow to one of the other two sppeds?

Strewth low on mine is serioulsy fast, I wonder what flat out sounds like, on mine the damn thing is already acting like a prop giving a bit of forward thrust :)

taking that one step further and re your PM perhaps I have a problem with mine as well I don't think it is running at anything other than flat out maybe the system defaults to that if the other speeds have failed
I need to look at the wiring diagrams on a certain CD, 2003 here I come so back later!
 
#27 ·
Keith Alexander said:
what is in this relay box one relay or more? any electronics passive or otherwise?
Anyone know how the speeds of the fan is achieved is it simply by using a resistive load switched by these relays, or is it done by electronics?
Click to expand...
The 1.8 has two relays, the KV6 has three and the M47R has four.

They are controlled by the ECU and work in a similar way to a wiper motor, ie the different connections to the motor windings vary the speed rather than resistors in the feed.

The petrol models are have only relays in the unit which are switched directly from the ECU, the diesel has a pulse converter as well, as the output from the ECU is pulsed and the converter switches the relays.
 
#28 ·
Rover_ron said:
Keith enquired about fan speeds and which speed was normal with the a/c on.

I've just tested them using my ACR4.

In fact there as 3 speeds.

Low sounds like normal a/c speed.
Medium is a bit louder
High is hovercraft mode - noticeably loud!

I thought that perhaps the ecu alters the speed depending on vehicle speed because sometimes when slowing down for junctions, the fan note changes as though its speed is altering. But I can't recreate this by letting my speed drop by coasting!

Ron, how about putting her up on axle stands,put it in 4th, then use throttle cable to increase and decrease speed. just don´t stand in front!!!!!
Click to expand...
 
#29 ·
dustybin said:
Ron, how about putting her up on axle stands,put it in 4th, then use throttle cable to increase and decrease speed. just don´t stand in front!!!!!
Click to expand...
I said this in another thread

Vroom Vroom Weeeeeeeeeeee crunch :)

Ron I think has a visit planned to the Dyno rig shortly maybe a test to try there
 
#31 ·
Keith Alexander said:
I said this in another thread

Vroom Vroom Weeeeeeeeeeee crunch :)

Ron I think has a visit planned to the Dyno rig shortly maybe a test to try there
Click to expand...

I have now received Madone's old an assembly.

It consists of the fan motor (permananet magnet type) and the relay box.
Inside there are 3 relays and a pcb with lots of smd components on the under side. One relay for each speed.
Therer is a Lm2901 quad comparator, half a dozen transistors, and numerous passive components.

It connects to the cars wiring with 30amp + & - supply cables and 3, 1amp signal cables that connect to the engine ecu, the a/c 3way switch and the engine ecu supply relay.
I don't know what has failed yet, but there isn't anything that could not be replaced for minimal cost, (unless the motor was burned out) though soldering smd components needs better eyesight than mine! (or a large magnifying glass!)
Since the ecu can select each of the speeds, and there is only one connection from it, the signal from it isnt simply an on/off one. Hence the complexity of the design.

to be continued....

Ron
 
#32 · (Edited)
Blimey just had a look
Where are the four big resistors? are they encapsulated with the Fan motor if not what value are they the circuit diagram looks very odd there is even a resistive load in the ground wire!

The fan seems to have three seperate speed related windings or that is the impression from the circuit diagrams and that begs the question why use resistors as well?

As you said there is an overide from the AC to the pcb

There is an indicated 80A fuse on the drawing

The external relay is low power and only provides power via a 15A fuse to the control PCB and good starting point if the entire fan is dead

The PCB Ron I think is just a pulse converter
i.e X pulses per second keeps the low speed relay engaged
Y pulses the medium speed one
Z pulses the high speed relay

I doubt if it is two way or much more inteligent than that

Do you have a scope? If one way this should be simple to emulate with a signal generator

Are the wires to the fan actually accesible?
 
#35 ·
Raykay said:
There aren't any resistors, its all down to the motor windings, with the relays controlled, as you say, from a pulse from the ECU.
Click to expand...
Ah but the Circuit Diagram shows four hence my question are they Encapsulated or is the circuit diagram wrong or are they actually something else

Probably the latter
easy way to tell buzz out the windings

Ron for the assembled audience lets have some pics of the inards just for a laugh :)

What we probably need to do if these thing are repairable is eventually turn the results into a sticky.

I am sure for a reasonable price we could come up with some sort of exchange repair process providing we had a float of three or four to start with?

That of course is assuming we can't find away of doing it in situ, which will also mean people have to pull their cars apart (a bit) so perhaps not everyones cup of tea!
 
#37 · (Edited)
Which diagram are you looking at, if it did have resistors, for a motor that powerful they would be very large and need substantial heat-sinks. There are none in the wiring diagram I have got.

If we're looking at the same diagram, the two 'blocks' either side of the motor represent the main brushes, the two 'arrows' at top and bottom represent the speed control brushes.
 
#40 ·
Sorted it - we're both right, we're looking at different diagrams, apparently the saloon has not got any resistors, but the tourer has.
 
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