Blender motor blues

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Pete D

New Member
Posts
23
Location
Morpeth
Hi All
Every winter for the past 3 or 4 years the textbook symbol appears on the heater control panel of my P38 and the flaps seem to stick in one position. Then in the Spring it all returns to normal. I suspect that this is just another silly trick that the car plays on me for some unknown reason but this year I was ready for it. Sure as s£!t November came and there it was :confused:.
Pre armed with a new blend motor I ripped all the relevant bits off and now when I turn on the ignition I can see the flap gear go fully one way then the other, then the sign comes up. If I select different outlet options the gear doesn't move at all. Surely this means that the motor is working but why doesn't it go to the selected positions? :( and why the seasonal variations?:fighting:
Any suggestions most welcome
Thanks
Pete
 
Thanks for thr quick reply. Sorry I didn't make it clear in my post but it's still the original motor that's on I didn't see the point of hacking into the trunking to change it when it appears to be working. Maybe a trip to my local specialist would be a good idea to get the diadnostics done.

thanks again

Pete
 
The motor has a potentiometer in it that signals the Hevac unit how far it has travelled. So if the potentiometer is at 10% and you select a heater setting that is say at 50% the Hevac drives the flap until potentiometer is at 50% of it's travel, the Hevac reads the signal from the pot then the Hevac stops the motor. When you switch the car on it does a self check. Confirming that everything is as should be according to the present settings. If your particular motor is supposed to be at say 15% as requested by the Hevac unit but the Hevac is not getting a signal from the pot that it is at 15%. The motor will run to try and find that setting, it will travel from min to max and back trying to do that. If there is no signal from the pot it will stop after cycling and put a fault up.
 
Last edited:
Update on Blend Blues.
Removed all the relevant bits including the air distribution blend motor or servo and didn't have to mangle the plastic ducting at all, just sort of push it out of the way to get to the far screw on the motor. The mechanism seemed pretty stiff so I went for the self tapper trick which certainly freed it off. New motor on and the first time I switched the ignition on the symbol came up but seemed to sort itself out and is hiding now........till the next time.:D I love a happy ending. Took a photo of self tapper location if anyone would like a look
 
Pete D said:
Update on Blend Blues.
Removed all the relevant bits including the air distribution blend motor or servo and didn't have to mangle the plastic ducting at all, just sort of push it out of the way to get to the far screw on the motor. The mechanism seemed pretty stiff so I went for the self tapper trick which certainly freed it off. New motor on and the first time I switched the ignition on the symbol came up but seemed to sort itself out and is hiding now........till the next time.:D I love a happy ending. Took a photo of self tapper location if anyone would like a look
Click to expand...

Well done don't see any photo though. :)
 
2012-11-21 14.47.16.jpg

2012-11-21 14.47.33.jpg
 
Hi Lizalandy

I didn't have the time or the courage to do the dash out routine so I took the footwell side panels, radio and upper switch panel, instrument binacle and surround out as detailed in the internet article on blend motor relacement. Not too bad really just bits of plastic but a bit time consuming. I was only interested in the upper (distribution ) blend motor which by now was fairly accesible but the lower motor ( temp I think ) was still half hidden by the rear duct trunking. Working through the hole where the instruments go I think it could be modified or bent out of the way to gain access. The internet article suggests being a bit ruthless as it doesn't do much anyway. It seems to be a slip on fit at the bottom and I wonder if it could be somehow cut off near the top and neatly joined up again with a bit of thought and some duct tape. Could be worth doing a permanent mod to make it easier the next time. :( I'm a P38 man. There will be a next time.
Good luck
Pete
 
Last edited:
Saint.V8 said:
Can't. you've still got them...you never let me hold the camera...you said the amount of 'lube' I had on my hands would be dangerous as I could drop the camera...:p;):D:D
Click to expand...

Don't say things like that on here people may get the wrong impression.















PS. When's next meet? :D:D:D
 
stjohnsmythe said:
Apologies for resurrecting this thread but can anyone confirm what size self tapping screw is sutiable for this mod? Thanks
Click to expand...

On the first photograph the bolt head to the left is 10mm across, the ones to the right of it are 8 mm across. So judge the head size of the self tapper from that. Would think it would be a 10 or 12 sized screw from that logic.
 
Great post and thanks for taking the photos. As a prospective P38 buyer blend motors are one of the things I'm concerned about, and now I at least know you don't have to rip the entire dash to pieces to poke about with them.

I used to have a Jeep Grand Cherokee and replaced the blend doors in that; a procedure that involved taking out the glovebox and slicing an access hole big enough for my hands through plastic ducting with a hot knife... That was fun, not.
 
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