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Take the distribution motor off the heater box so it is dangling on it's cable. You should have enough slack to be able to move it in front of the instrument cluster (assuming you've gone in that way), plug the instrument cluster back in and sit it in place. Hold the spindle on the blend motor and turn the ignition on. The system will do it's self test by moving all the motors and checking for a valid signal back from the feedback pot. Make sure it does turn. If it does, it isn't stalled but there's no feedback so the HEVAC doesn't know it is moving. If it doesn't, it's knackered.

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Thanks Richard. The distribution motor works when attached as you can see the quadrant moving.

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Use the Nanocom to check that it is seeing feedback. Go to HEVAC - Utilities - go to the second page and force the Distribution motor to 0%. While it moves it will show the feedback as a percentage and should go down to 0%. Then poke the button and change it to 100% and force again. You should see it move and the feedback should move from 0% to 100% (or 106% as mine shows which is a good trick if you can do it).

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i've forced the distribution motor in both directions and forcing to zero shows Out 0%. In 85% and forcing to 100% shows Out 100% and in 85%. but the flap doesn't move.

When I return it to the ecu control the original faults show and if I clear those it comes up with left blend motor short circuit to positive but the others are cleared.

With the distribution motor off it does move slowly on initial turn on.

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Nanocom does get it's left and right messed up at times, so may be confusing the distribution motor with the left motor so reporting a fault on the wrong one. If the HEVAC has detected a fault on a blend motor it doesn't try to move it. Staying at 85% means it isn't moving, if it was you'd see it move from where it is to either 0% or 100% depending ion which you have told it to go to.

The other way of checking, is to use the Inputs - Values menu. That shows the current state of the feedback from each blend motor. So if you change the temperature settings from Lo to Hi, you'll see the position change. Same with the distribution motor if you change the airflow from floor to screen, you should see the % change. However, bear in mind the above, if it has detected a fault it may not try to move the motor so the feedback won't change.

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So on that basis do you think it is because the flap is too stiff for the motor to move it or is the motor too weak?

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When you first turn the ignition on and it does it's self test, you said the motor moves when dangling on it's cable but does it still move when attached to the flaps? I think you said it does. In which case, it is a lack of feedback so while it is moving the HEVAC isn't aware it is moving so thinks it has stalled.

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No, it will move slowly when detached but the flap doesn't move on self test. There is a bit of a hum but no sign of movement of the quadrant.

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Sounds like the motor is weak or the flap is stiff then. If you can move the quadrant by hand from end to end that should be OK but bear in mind that the quadrant drives two cogs, one at the top and one at the front as well as a lever at the back. The blend motors are fairly easy to take apart and I've got one working again by spraying contact cleaner into the motor and hitting it with 12V in both directions so it drove both ways. With the lid off, the motor has two tabs that slot it onto the circuit board so it pulls out. When you put it back together, note that the main cog that drives the quadrant has an arrow on it as does the cog on the pot, they need to be lined up (a bit like timing marks).

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The quadrant will move by hand but it is a bit stiff at the last couple of teeth. I'll try giving the motor a clean.

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Having got mixed messages from the Nanocom and the RH blend motor having given up altogether I've ordered a set of Valeo motors from Island 4x4 and removed the whole dashbaord.

The left and right flaps move easily but the distribution flap is still a bit stiff right at one end of the travel. When the new motors are in I'd like to test them before putting the dash back. Mindful of warnings not to start anything without having instruments etc connected can I just reconnect the HEVAC and instrument panel in order to test things?

Thanks again.

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Dear All,
As far as I know as long as the instrument binnacle and the passenger air bag are connected you will be fine. I drove mine around for about a month having removed the dash but replaced the passenger air bag on the frame, duck taped the switches and light selector together and the instrument panel to a couple of gash brackets i had lying around. Looked rather odd, a sort of skeleton dash but it all worked.

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As Paul says, yes you can. As long as the instrument cluster is connected you won't offend anything.

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Thanks Paul and Richard.

Any views on how much resistance there should be in the distribution quaadrant? It's better than it was but not as smooth as the other two.

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The distribution quadrant is stiff compared to the others. The others are just moving a single flap and not at least 3 like the distribution flaps so it's going to be stiffer. Just how stiff is too stiff is a different matter though. There's a bodgers method of freeing them without taking the whole heater box out and stripping it down in post 25 here https://www.rangerovers.net/threads/photos-of-method-for-freeing-blend-flaps-with-s-t-screw.14322/page-2 (click on the thumbnail picture to see all of them).

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There's a bodgers method of freeing them without taking the whole heater box out and stripping it down in post 25 here https://www.rangerovers.net/threads/photos-of-method-for-freeing-blend-flaps-with-s-t-screw.14322/page-2 (click on the thumbnail picture to see all of them).

Only worked temporarily for me. I can move all 3 with a 9v battery no problem full end to end. Put it into HEVAC control book within minutes

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Thanks Richard and Hoppy,

I'll see how the new motors work out before I put it all back togerther again.

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if you have removed the dash fix the air box . it has to be removed completely and taken apart , free up all the flaps . when you are done the flaps will move with the flick of a finger. the problem with plastic is the solvents in it dry out and the plastics shrink (thats why dashes in cars rattle after several years) making the flaps hard to move , sand the ends where the flaps insert into box and give it around 2 mm clearance on the shafts . just unclip the clips holding it together and it will fall in halve , a power file is good to use , may take a couple of goes to get it right but you will not have to deal with this issue again . don't forget the white drive gear on the distribution motor this can be tight to so may need some attention to . why patch when you can fix it properly.

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As Mad-as says... I've pulled a number of the heater boxes apart and freed up the flaps in them. I usually ream the holes out in the heater box itself to give a bit more clearance for the flaps to move in, and also I've found in a number of them that the grease that was used originally had dried up and also instead of keeping things moving nicely actually helps bind things up.

I use silicone grease when putting them back together, rather than the white lithium grease (as it seems to get less greasy and more solid with age).

Also worth checking the alignment of the gears on the main grey spindle, as if they're out a bit then one set of the 3 flaps will get to the end of motion before the others and stall the motor out.

I've also found on a few heater boxes that the drive shaft from one of the sets of flaps has slid out over the years, so one set of the distribution flaps isn't driven properly (if at all).

Incidentally - the last few heater box out/heater core/blend motor swaps I've done for other people have been on later 2000/2001 vehicles and the heater boxes haven't needed any work and seemed a LOT freer than earlier ones. So I wonder if there was a slight modification in the production on them, as the later ones did have a different part number....

I believe you should be able to move ALL of the flaps (including the distribution flaps from one end to the other) with your little finger. The motors have a fair bit of torque in them due to the gearing, but obviously the freer the flaps, the easier life the motors have. I've managed to get some of the earlier heater boxes to be pretty freed up - but a couple of the later 2000/2001 versions that I've pulled out have been really free and easy to move - which makes me think they must have adjusted the tolerances in later production.

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Thank you Mad-as and Marty.

As this is my first time delving inot the innards I am rather cautious. Can I get the air box off without having to drain the coolant and take the whole business out?

The distrubtion flap is definitely not a finger flicking exercise.