P38A HEVac

cornishboater · May 31, 2019

Before I get everything changed or buy the wrong ones, my HEVAC is only blowing cold on both sides, if I select heat (on each side or together) it just remains the same, cold. The blend flaps distribute up an down (albeit sometimes squeaking) The blend motors I have found come as a 3 pack so will this fix this issue? The other very noticeable thing is that the page fault comes up even before the HEVAC starts (basically as soon as you turn the key to start) This is in both manual and auto modes, AC on or off. Is this more likely to be a matrix core temp sensor issue, I have no way to test so I have bought a new temp sensor just in case. There is heat going to and coming from the heater matrix and to the LPG unit so I assume I can rule out a blocked matrix. I have a great guy down in Devon that can do the blend motors and change the "o" rings but I want to make sure I get the right ones for him to change if that is the issue. I understand that there are 5 motors in total, are the other 2 for the fresh air intakes (one is constantly open, I haven't investigated why yet)

Many thanks for any info

kermit_rr · May 31, 2019

I've got a blend motor project on the sidelines at the mo, I'm going thru the process of testing and replacing the pots target than the whole unit.
From what I've done so far, I think after so many attempts, the hevac guess into a hard fault and you have to disconnect the connector from the back to reset it.
The motor will then attempt to cycle in both directions to see if it gets the expected values and if it doesn't then the book comes back
I might be seeing but that's how it seems so far

fucmeitsandy · May 31, 2019

After I had the blend motors changed i had a look in side them . The one that was causing the fault was jammed with a bit of dry grease , I thought maybe I should have tried forcing them before getting them changed .

kds · Jun 1, 2019

The motors come as a set of three colour coded pre wired to one plug, there are two other motors one each end of the dash that select either fresh air or recirc.

RangeRoller dt · Jun 1, 2019

They can just die but they dry out and jam mostly I hear. Not as trouble some a job as most would think I’m told

Your AC (if you have it) is off yes, as in AC light on?

cornishboater · Jun 1, 2019

I have tried with AC on and AC off (light on) Manual an Auto, same scenario each time

Datatek · Jun 1, 2019

cornishboater said:
I have tried with AC on and AC off (light on) Manual an Auto, same scenario each time

All 3 main blend motors are the same, one for distribution, two for temperature. If the connectors don't match, I just cut and join the wires.

cornishboater · Jun 1, 2019

Many thanks Data, So if I have cold from both sides it would have to be 2 motors/or flaps stuck? the blend up and down is working fine (apart from an annoying squeak when moving...) I am tearing into the beast today to see if I can get some Teflon lube in and attempt to change the sensor. What could go wrong..

wammers · Jun 1, 2019

cornishboater said:
Many thanks Data, So if I have cold from both sides it would have to be 2 motors/or flaps stuck? the blend up and down is working fine (apart from an annoying squeak when moving...) I am tearing into the beast today to see if I can get some Teflon lube in and attempt to change the sensor. What could go wrong..

Blend flaps don't usually stick. On the motors i have stripped and repaired the problem has been carbon dust buildup around the motor armature causing shorts. On reassembly the marks on the pot gear and main gear MUST be lined up. DO NOT power the motor until it has been fitted.

cornishboater · Jun 1, 2019

Cheers Wammers, I have read on one post (which I cant find now) that the motors can be removed without taking the whole dash out by cutting and splicing the wires, is this correct?

wammers · Jun 1, 2019

cornishboater said:
Cheers Wammers, I have read on one post (which I cant find now) that the motors can be removed without taking the whole dash out by cutting and splicing the wires, is this correct?

Yes. But if you do that vary the joints or you will have a big clump of joints. Not very pretty. Solder and heat shrink does the job. Splay the wire on each joint. Put one splay into the other and twist together for a smooth join and solder. Not forgetting to have a bit of heat shrink slid on one of the wires. Slide over joint and shrink, job done.

cornishboater · Jun 1, 2019

10-4, luckily I have loads of heat shrink (one needs a lot for a P38) I might invest in one of those auto feed soldering irons, unless I can grow another hand

I will have to re-find the link to the method used to remove them though I think

pwood999 · Jun 1, 2019

Is the heater matrix actually getting hot ?

cornishboater · Jun 1, 2019

Yep, nice and toasty down there, just not coming out of it at the moment

P38A HEVac

cornishboater

Well-Known Member

kermit_rr

Very

fucmeitsandy

Well-Known Member

kds

Well-Known Member

RangeRoller dt

Well-Sprung Member

cornishboater

Well-Known Member

Datatek

Well-Known Member

cornishboater

Well-Known Member

wammers

No longer with us, RIP

cornishboater

Well-Known Member

wammers

No longer with us, RIP

cornishboater

Well-Known Member

pwood999

Well-Known Member

cornishboater

Well-Known Member

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