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Discussion Starter #1
Yesterday I decided it was time to investigate the distribution/blend servo issues as it was blowing cold air to drivers side mild to the passenger and all going to the front windscreen.
So after Reading the stickie I went for the distribution servo first as it sounded the easiest to get at.
So removing the trim I watched the White plastic gears (as shown in the photos) to see how much movement was noticeable and very little was the outcome. So while switching the ignition to see the servo go through it's auto check I used a long flat blade screwdriver to add a little extra push pull to the gear and it worked it moved passed the point at which it was stalling and continued to move through it's full range of movement.
But not wanting to give up at this stage I just used a broad flat bladed screw driver to separate the distribution box then I inserted the plastic tube from a can of silicone spray and a few squirts later the unit was running like new.
The next problem was the blend motor drivers side as it was bloody freezing.
After Reading the info on these my thoughts where leaning towards another stuck flap rather than a unit that had stripped teeth as I would expect to hear a motor running but nothing moving if this was the case and all was quiet.
So using a spare wooden hammer shaft I rested it on the top of the blend servo and with the handle of the large I screwdriver I give it a few taps and it sprang back into life distrbuting lovely hot air to the drivers side I still can't belive my luck but for those with servo issues it has got to be worth a bit of spray and a few taps of the motors just in the case they are stuck.
 

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Did you have/get rid of the book symbol? I had similar issues, on running again after 2 years off the road. Cant beat a free fix! And book symbol gone. Good job too, had already spent £100 on a blend motor just before it came off the road. I put mine down to lack of use.
 

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I had a distrubition motor that would stick and display the book symbol so i removed the centre vents in the dash and drilled a small hole in the heater box and a squirt of WD 40 cured that problem, it sometimes does it again but another squirt and it ok for another 6 months, i have also had a blend motor stuck on hot on the drivers side and i said to the wife i will do that blend motor today so sat in the Rangie and thought i wonder :idea: , opend the bonnett removed the two polon filters and turned the heater fan on fast and squirted some freeze and free spray in the heater intake and "nothing" so i decided it was to cold to pull the half the dash to bits and went in, next morning i got in and no book symbol and i can control the temp both sides and problem gone., that was 4 months ago

Dont know how or why it worked but it did
 

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Discussion Starter #4
Book symbol has not gone as I didn't bother with the Passenger side but i will now things are looking favourable after a hit or two with a hammer shaft. :thumb:
But thats next weekends job.

I put mine down to lack of use. it's a good point you make and makes me wonder, when these units are set to auto there must be very little movement of the flaps and over a period of time they probolay do get lodged/stuck in position due to flexing of components etc.
 

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I think there's more movement in auto, as it's trying to maintain a precise temp, not jut "about right..."

also, every start-up the HVAC goes through a full cycle of the flaps as a self-diagnostic, so they get exercised fairly frequently.
 

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Discussion Starter #6
shupack said:
I think there's more movement in auto, as it's trying to maintain a precise temp, not jut "about right..."

also, every start-up the HVAC goes through a full cycle of the flaps as a self-diagnostic, so they get exercised fairly frequently.

Hi Dennis the jury is still out on the auto maintaining a more precise temp and moving about more over here there is less of a big shift in ambient temp therefore i suspect the system has less to compete with.

As regards the HVAC doing a full cycle on every turn of the ignition key I'm not convinced.
After playing around yesterday I noticed that the distribution servo didn't do a self diagnostic every time I swithched the ignition on but wether this was due to me not fully returning the ignition to the fully off position I can't honestly remember,but on turning it fully on the servo stayed in the same position untill I manually set the airflow direction then the servo moved.
 

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the system does a full test every tenth operation, ie every tenth time you turn on ignition

Book symbol comes up for a number of reasons and not only blend motors
 

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Also the HEVAC gets power from multiple sources.
The logic circuits turn on with the Ign-I (= "accessory"), but the display doesn't give any output until Ign-II (= "run"). It's not fully operational until it sees output from the Alternator. The blower fans are powered from two relays in the engine-fusebox.

If you should ever have any faults logged on the HEVAC and clear them (say with Autologic), you need to switch to Ign-0 (or even key out), before restarting the HEVAC (Ign-II+). Otherwise, the HEVAC will continue to show the same faults you think you have just cleared, as the logic circuits hadn't powered down.
 
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