Windscreen vent dont blow hot or cold p38?

Hey chaps, getting round to the niggles now the rangies back on the road. Can anyone help, the heater works well however the two side vents and windscreen vents don't blow anything at all, no hot or cold. Any tips on repair.

Cheers in advance lads.

I think there is a blend motor that alters the air flow direction. They are prone to failure im told!

Dash out repair i think!

sorry when i say blend motor I mean the directional one, not temp control

I have just had mine in the garage and they could not find a problem with the motor that does the direction. air moves from feet to face, just not to window. so direction motor is working

if anyone does have an idea i would like to hear it too.

if i figure it out will post solution

gibby_wls said:

I have just had mine in the garage and they could not find a problem with the motor that does the direction. air moves from feet to face, just not to window. so direction motor is working

if anyone does have an idea i would like to hear it too.

if i figure it out will post solution

Click to expand...

If it isn't going all the way to the top, then it isn't working correctly....

If you can get it on a full fat diagnostic device like a Faultmate Extreme, Autologic, Testbook et al, and do a calibration of all the blend motors as they will need to be told what their full range of motion is....

Also the Diagnostic Device will be able to force the motor to all the positions....if the Device says it should be at windscreen and nothing is coming out, suspect a blockage....

Get it on a diagnostic device first to calibrate and force position, as replacing the blend motors is tricky so make sure it is not a software/ECU fault first....

they had it on T4 and did re-cal and could get the motor to 100%, just an asthmatic breath coming out the vent, it does sounds like its blowing behind the dash somewhere

gibby_wls said:

they had it on T4 and did re-cal and could get the motor to 100%, just an asthmatic breath coming out the vent, it does sounds like its blowing behind the dash somewhere

Click to expand...

Then I would suspect a blockage or the vent ducting has either been disconnected or split imho....

Right, that's a complicated fix. So diagnostics are the way to go first, looks like.

Does this new nanocom do this kind of test? Was looking for one at some point anyway, looks like this is a reason to buy one.

cljcars said:

Right, that's a complicated fix. So diagnostics are the way to go first, looks like.

Does this new nanocom do this kind of test? Was looking for one at some point anyway, looks like this is a reason to buy one.

Click to expand...

The Wammer of Datatek are more knowledgable on the Nanocom Evolution than me....but I would think so as it is based on the Faultmate Extreme Software....

I would deffo get it on a diag machine just to confirm the calibration and to force the distro blend motor to windscreen first, as this would be easier than checking the ducting or removing/replacing the motor.

Ok, cheers for the help, much appreciated.

The distribution motor is the easiest one to get to. Assuming yours is rhd take off the under dash panelling on the driver's side and look into the middle. You'll see the motor or at least the white toothed quadrant turning (or not) when you activate the switch. If the teeth are stripped at all then the flap could be stuck. You could manually turn it to have it midway and put up with it until you either want to do the full dash out trick or just leave it like that. As long as the heat ones are working. One of mine wasn't in October so the lot had to be done.

Hey, thanks for that info. I will have a look today. Is it above the matrix heater pipes behind/above the main vent that leads to the underneath of the seats?

I remember seeing this when I took the matrix out in the summer.

Cheers

cljcars said:

Hey, thanks for that info. I will have a look today. Is it above the matrix heater pipes behind/above the main vent that leads to the underneath of the seats?

I remember seeing this when I took the matrix out in the summer.

Cheers

Click to expand...

On the drivers side there are two motors...the lower one is horizontal and is the temperature motor, the vertically mounted one above it is the distribution motor....

When he says easier...it is a still a pain, but you dont have to dismantle most of the ducting to get to the mounting screws...!!

Cheers, bottom one has to be released to get the matrix out, I had to anyway. I will have a look around on the weekend, car is blowing hot so I will move the top vent open for now.

Cheers

Right, Pulled the drivers side pannels off and the vent i cut out to get the matrix out. This gave access to the lower blend motor. I checked this out by going from hot to cold, no movement, locked, split it and manually moved it to hold the blend flap to hot. I couldn't get at the top one very easily, but as you described above this seems to be working, diverting the air as you select the different positions. I don't think it is working quite as good as it should, although now I can feel a waft of warm air comming from the windscreen vents. I can live with it like this. Warms up much quicker now though.

All Thanks for the help.

cljcars said:

Right, that's a complicated fix. So diagnostics are the way to go first, looks like.

Does this new nanocom do this kind of test? Was looking for one at some point anyway, looks like this is a reason to buy one.

Click to expand...

Yes it calibrates and forces the motors just had a play with mine

I now have the same problem. No air is getting to the windscreen vents. Temperature works fine, and I can get air out of the footwell and face level vents. Fans work great, minimum to maxumim speed is all selectable.

I have taken the disribution motor off and can move the lever it's full travel by hand (moves pretty freely), but still no air comes out of the screen vents....? The various levers and cogs on the side of the heater box are all meshed properly, and seem to be moving as expected.

I assume it must be a blockage? But before I start thinking about taking the dash out, does anyone have any other ideas?

If it is a blockage, is there anyway I can poke long things down the slots to unblock it? I can't really understand how it might've got blocked with anything to be honest....

Could be the flap shaft turning in the gears. Are the gears properly aligned ?

I haven’t taken it apart anymore than just removing the motor, and it did work perfectly until it didn’t, so I assume it’s all aligned properly. I was wondering if I took off that top bit of ducting, can I get a hand in the box to see what’s moving and what’s not???

I can’t understand if it was seized anywhere, why I can still get air to the feet and face?

There's some pictures on this page showing the flaps. https://www.mez.co.uk/p38-heater-o-rings4.html

Could be they are not moving together ?