Having finally managed to rebuild a 24v blower units for my S3 FFR and getting it to fit under the wing in the correct spot it came time to check it out. First problem was found when, having temporarily connected the wires under the bonnet nothing happened. Checking the Brown/Orange feed wire to the switch got a reading of 0v instead of the expected 24v whilst at the ignition switch end there was 24v. Seemed odd so I went and had a look at the wiring diagram and found there was an in-line fuse in the feed. Rain then stopped play until today.
We actually had a dry spell today for the first time since Sat afternoon - so I nipped out fast to the Landie. Found the in-line fuse for the heater fan - what a stupid place to locate it under the inner dash pod - and mangled the hands cracking the holder open and fitting a new 35A glass cartridge fuse. You'd think the lead from the out side of the fuse holder to the switch would go direct to the switch but no - it seems to go in a taped section of the loom first so you cannot pull the fuse holder out from under the pod.
Once it was in and the holder done up again I checked power at the switch end of the Brown/Orange feed and had 24v. Connected it and turned on the switch - nothing. Popped the bonnet and found I'd forgotten to reconnect the 2 leads from the vehicle into the double female bullet connector - did the ones from the fan motor but not the vehicle side.. Once they were plugged in, I turned power on and the fan started.
With the switch in the off position!!
Flicking it to the on-1 and on-2 positions just turned the fan off. I think the switch might be wired incorrectly.
It's as it came with the vehicle so I had no reason till now to question the connections.
Basically there are two male terminals at the top of the switch - the power in lead goes to the R/H one of these. I tried it on the L/H side too - no change, Then there are two male terminals projecting from the back of the switch with the Green/Yellow and Green/Brown leads on that go to the fan motor.

Does anyone know how this switch is actually meant to be connected as I cannot get the dash out far enough to run connectivity checks with a multimeter, nor can I get the switch out of the dash without risk of damage to the dash.

I don't understand how you can see it well enough to take a picture but not have enough room for multimeter leads? Even so, can you not make a couple of leads with spade connectors to attach to switch and meter?

Photo was taken by wedging the phone's camera into the gap - about 3/4" - between the pod and the panel. My fingers barely fit, I can just about reach to get the Brown/Orange lead off to check the supply, Can't reach the lower terminals properly - maybe enough to get those off and off. So it seemed simpler to ask if anyone knew the correct way that switch should be wired before trying to faff about with fly leads.
That's the way its been wired since I got the vehicle in 2006 and it;s taken this long to get a working RHD 24v heater blower that works as the original was missing..

Forgot to mention the other reason why I asked here first - it's been hammering down with rain more or less none stop since Sat evening and one thing I have learnt over the years is that going near the 24v electrics of an FFR when it is damp, let alone wet, is a painful experience.

However - we had another dry day today so I did get the multi-meter out - and wound up even more confused.
If you say the two top terminals are A & B, the top of the back terminals is C and the bottom D as in this (crude) diagram:

I get the following:
Switch in OFF position
A connects to B
A connects to C
A connects to D

B connects to C
B connects to D

C connects to D

Switch in Position 1
B connects to C
B connects to D

C connects to D

Switch in Position 2
B connects to C
B connects to D

Looking on Craddocks web site they actually list two switched for the Series 3 - which double up as head/side lights on civilian models.
One is Lucas 1H9077LG
The other is 1H9077L - no maker specified
Both look like what is fitted to the vehicle so I am now totally confused.

Looking at this photo

The switch is in lower side of dash with the twin edge top contacts in your depiction at the bottom, the two greens[Green/ Yellow & Green/ Grey] on lower edge are the two speeds to the fan.
In this picture the brown connected to the centre connection is the supply.

Note the 12V and 24V wiring should be the same just the motor will be rated and wired for higher voltage.
Hope that helps

Blackburn said:

Looking at this photo

The switch is in lower side of dash with the twin edge top contacts in your depiction at the bottom, the two greens[Green/ Yellow & Green/ Grey] on lower edge are the two speeds to the fan.
In this picture the brown connected to the centre connection is the supply.

Note the 12V and 24V wiring should be the same just the motor will be rated and wired for higher voltage.
Hope that helps

Click to expand...

Thank you very much indeed!! That is a tremendous help. All these years mine has been in upside down and incorrectly connected - never know these things until you see one that is wired correctly. As soon as the rain stops = again - I'll get mine connected this way and see what happens. I actually managed to get the switch out today in a dry spell using circlip pliers to undo the locking ring.

Switch now wired correctly and working.. Well - at least the motor is spinning, not actually feeling anything coming out of the screen vents but the fan does now spin up Thanks to everyone for the assistance it was much appreciated. Onwards now to the next problem