P38A Heater problem - stuck on demist

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tank93

Active Member
Posts
155
Hi all, need some guidance please. The direction control buttons on my heater panel don't work, the heater is stuck on demist mode so only get air to the windscreen. If I press the button to select face or footwell distribution nothing happens, the heater continues to blow the air on the windscreen despite the panel light showing I have selected face/footwell. Does anyone know what the problem could be? If it makes a difference my P38 has the manual heater control panel with rotary knobs to control temperature and fan speed and has no air con. Thank you
 
Hi all, need some guidance please. The direction control buttons on my heater panel don't work, the heater is stuck on demist mode so only get air to the windscreen. If I press the button to select face or footwell distribution nothing happens, the heater continues to blow the air on the windscreen despite the panel light showing I have selected face/footwell. Does anyone know what the problem could be? If it makes a difference my P38 has the manual heater control panel with rotary knobs to control temperature and fan speed and has no air con. Thank you
The blend motor has failed is the most likely cause. The manual control still uses the blend motors. could just be the distribution flap has become too stiff for the motor to move it.
 
Hi all, need some guidance please. The direction control buttons on my heater panel don't work, the heater is stuck on demist mode so only get air to the windscreen. If I press the button to select face or footwell distribution nothing happens, the heater continues to blow the air on the windscreen despite the panel light showing I have selected face/footwell. Does anyone know what the problem could be? If it makes a difference my P38 has the manual heater control panel with rotary knobs to control temperature and fan speed and has no air con. Thank you
Ooer, dashboard diving🥺
 
Ah ok so distribution blend motor then, take it its not easy to replace then?
Access is not that easy, the distribution bend motor is on the RH side where there are 2, I can't remember if it's the top one or the bottom one, the drawing does not make it clear.
1707580598435.png
 
I am seriously tempted to buy some of these universal cable operated knobs and doing away with the blend motors.
If anyone has a broken manual dial HVAC head unit they want to sell cheap, I'd like to have an experiment with one.
On eBay they are over £100.
 
Is it a job that can be tackled alone or do you need two people to get the dash out? Never attempted anything like this before but willing to give it a go over the next few weeks if the weather improves!! It will probably take me a long time to do because I am no mechanic but hey its got to be done. Is there anything in particular I need to look out for, any real difficult parts of the job or is it pretty straightforward if you take your time? Is there anything else I should be doing whilst the dash, i.e. should I replace the other two blend motors or just the dodgy one? I see lots of posts about heater matrix leaks and o'ring leaks, I don't have those issues (at the moment) so is it better to leave well alone if no leaks or better to replace whilst dash is out? Thanks
 
Is it a job that can be tackled alone or do you need two people to get the dash out? Never attempted anything like this before but willing to give it a go over the next few weeks if the weather improves!! It will probably take me a long time to do because I am no mechanic but hey its got to be done. Is there anything in particular I need to look out for, any real difficult parts of the job or is it pretty straightforward if you take your time? Is there anything else I should be doing whilst the dash, i.e. should I replace the other two blend motors or just the dodgy one? I see lots of posts about heater matrix leaks and o'ring leaks, I don't have those issues (at the moment) so is it better to leave well alone if no leaks or better to replace whilst dash is out? Thanks
I have the same issue on my project P38, lovely hot air on the screen only, seem to remember from my last P38 there was always a "clunk" as the direction motor switched the vents. Not sure if I can be bothered to fix it at the moment, especially as the weather is getting warmer and still have a long list of mechanicals and MOT work? Lots of info on blend motors but nothing on the distribution side. I think my blend motor might be OK if I can change the temp but not direction, so might just be stuck flap?
 
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