P38 heater - np heat to feet

Bakerwoodlands · Dec 15, 2011

Has anyone ever had a P38 where the servo's have all tested OK and no book showing on the display, and where the temporature changes OK both sides, and where you can manually select air direction to screen and vents sucessfully BUT not to feet? The light comes on above the switch as it should but nothing comes out either side or to the back (although you can hear the fans blowing). I have had it plugged in with no faults remaining and forced a calibration. Niether does it go to feet if you chose one of the combined modes (screen/feet or vent/feet).

If it did not direct to screen and vents when selected I would have assumed the distribution servo had failed despite the test showing no faults and no error in the climate screen, but in these two modes it works fine - you can here the servo moving and feel the air stop to screen as it moves to the vents etc - perfect, but not to feet!

It's like the ducts are blocked but completely blocked to both sides?

any ideas?

dogsbody · Dec 16, 2011

Bakerwoodlands said:
Has anyone ever had a P38 where the servo's have all tested OK and no book showing on the display, and where the temporature changes OK both sides, and where you can manually select air direction to screen and vents sucessfully BUT not to feet? The light comes on above the switch as it should but nothing comes out either side or to the back (although you can hear the fans blowing). I have had it plugged in with no faults remaining and forced a calibration. Niether does it go to feet if you chose one of the combined modes (screen/feet or vent/feet).

If it did not direct to screen and vents when selected I would have assumed the distribution servo had failed despite the test showing no faults and no error in the climate screen, but in these two modes it works fine - you can here the servo moving and feel the air stop to screen as it moves to the vents etc - perfect, but not to feet!

It's like the ducts are blocked but completely blocked to both sides?

any ideas?

I think it's more likely that you'll find that the ducts are missing or not connected. correctly. If a previous owner has worked on the heater for either the O rings or a blend motor I would wonder if he's just not replaced them correctly or at all. At least it's a reasonably easy investigation/fix, just a bit of time to get in there and a visit to a friendly breaker.

Bakerwoodlands · Dec 16, 2011

Thanks. Assume it must be something like this but can't understand why its the same both sides and that according to the manual all the ducts come from teh heater box so assumed some must work. As you suggest I'll take of the side panels and work my way back until I get some hot air. Thanks again for the reply.

hippolover · Dec 16, 2011

Your blend motor may be working and showing as calibrating but is the actual flap stuck in the heater maybe? Do you hear it opening and closing? A bit of partial dismantling on the right hand side will allow you to see the cogged quadrant which is turned by the distribution motor. The panel below the steering wheel should be all you need to remove to check.

dogsbody · Dec 16, 2011

hippolover said:
Your blend motor may be working and showing as calibrating but is the actual flap stuck in the heater maybe? Do you hear it opening and closing? A bit of partial dismantling on the right hand side will allow you to see the cogged quadrant which is turned by the distribution motor. The panel below the steering wheel should be all you need to remove to check.

Nice one HIPPO. Of course the motor may be moving perfectly but if it's not connected to the flap the air wouldn't be diverted.

Well worth a look even if all you do temporaily is move the flap the other way.

Bakerwoodlands · Dec 17, 2011

Great advice, thanks all. Thing I can't get my head around is will direct to screen and vents as directed with no bleed by manual selection every time but not to the feet? will remove RHS panel though as may be as you say a bit of the quadrent missing or not engaging. Although thought feet were direct from air box now looks like goes pollen filter/blower/hearter matrix/temp blender/direction flap/ducting so will also let me check ducting but can't see how all 4 ducts can be blocked. Will wait to risk of snow gone to check. Thanks again all.

hippolover · Dec 18, 2011

dogsbody said:
Nice one HIPPO. Of course the motor may be moving perfectly but if it's not connected to the flap the air wouldn't be diverted.

Well worth a look even if all you do temporaily is move the flap the other way.

If it does need a manual tweak, a 70/30 split, screen/ footwell is a good balance to keep the screen clear and your feet warm of course.

Bakerwoodlands · Dec 23, 2011

I am pleased to say I have now fixed my heater problem. It was not the motors or ducting in the end but instead the small black gear that runs of the top flap mech (and which is directly driven from the servo) had moved out sufficiently to be disconnected resulting in the "foot flap" being perm closed. Hence all the noise etc and the motor still going full deflection. Don't know how, or why, perhaps was removed during calibration of the servo. Removed the binical and the cog, got the HEVAC to go full screen, set the foot flap to closed and re inserted it. Works a treat! Thanks again for all suggestions.

hippolover · Dec 23, 2011

Glad to hear it. Sounded mechanical rather than electronic hence no fault showing up.

P38 heater - np heat to feet

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