T

tonybirch

New Member
Morning gents.
A few months ago I changed all the blend motors
on my y2000 p38. Which sorted the constant cold air
on the passenger side and cleared the book symbol
The book symbol has reappeared with the same issue
Constant cold air on pass side. Have removed the blend
motor on that side and wired in a good one that I have.
When I turned on the ignition the new motor moved at first
then stopped book symbol appeared. Can anyone tell me
which wires to test to check to correct voltage is being sent
From the hevac as i'am starting to suspect the fault may be with this
Many thanks
 
Hi,

I haven't any direct experience to your query but I spotted a good Swedish site with good info on blend motors. Range Rover P38 Maintenance repair improvements and tips learned by experience by ownership.

It shows how to fault find, the cable colours and what they do and how to fix them internally - good news if you're eating a few?

I've seen something elsewhere about the flaps in the heater box getting tight and overloading the blend motor. The quick solution was to put a self tapper inbetween the two halves of the heater to give the flaps more clearance. Another root cause may be leaves etc have got in and jammed the flaps?

Sorry, can't help with direct knowledge.
 
Have you tried clibrating them using a full fat diagnostic device?

Sometimes the system looses its marbles and forgets the blend motor set points.
 
Saint.V8 said:
Have you tried clibrating them using a full fat diagnostic device?

Sometimes the system looses its marbles and forgets the blend motor set points.
Click to expand...

I'm pretty sure the blend motors do a calibration sweep every time the ignition is turned on. No doubt someone will correct me if I'm wrong;)
 
Datatek said:
I'm pretty sure the blend motors do a calibration sweep every time the ignition is turned on. No doubt someone will correct me if I'm wrong;)
Click to expand...
I don't think your wrong....but I am not sure it is everytime the ignition is switched on, it could be every 100th time or whatever....I also stand ready to be corrected.
 
From rave.. they calibrate on thr 1st ,5th 25th 100th then every 500 power up......
 
Last edited:
Saint.V8 said:
Have you tried clibrating them using a full fat diagnostic device?

Sometimes the system looses its marbles and forgets the blend motor set points.
Click to expand...


Could be a faulty potentiometer or if the flap is binding and stalls the motor, the electronics think that is the end of travel. So the motor only moves the flap between closed or open and the bind. You can force a calibration with Nanocom. The post before this one tells you the auto calibrate time spans.
 
jt_armstrong said:
What is the datum point for this? Is it 1st etc time from first manufactured or since the battery was replaced?
Click to expand...

From first activation of Hevac i think. Think it is stored in Hevac unit. Don't know if it would zero if power was taken away for an extended period.
 
jt_armstrong said:
What is the datum point for this? Is it 1st etc time from first manufactured or since the battery was replaced?
Click to expand...
The HEVAC ecu self tunes on the 1st,10th,20th,50th,100th,500th and every subsequent 500th boot up.And battery disconnection will have no influence.
All info taken from Operation Pride.
 
You can certainly tell the HEVAC unit to re-start the flap calibration count with the Extreme. Re-calibration should be implemented when replacing any of the blend motors.
 
Last edited:
eightinavee said:
The HEVAC ecu self tunes on the 1st,10th,20th,50th,100th,500th and every subsequent 500th boot up.And battery disconnection will have no influence.
All info taken from Operation Pride.
Click to expand...


Bloody hell Vee that sounds like a gay service manual. :D:D
 
wammers said:
Bloody hell Vee that sounds like a gay service manual. :D:D
Click to expand...

Nah, I suppose it does sound a bit dodgy.Actually a S.I.D.S. from LR.(Systems information document) They were produced to help LR staff help techs in dealerships,they contain way more than Rave,some of them even have scope waveforms showing good and bad traces etc.
 
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