View Full Version : hevac repairs
roverv8
25th January 2020, 03:55 PM
ok, so after yrs of owning classics and discovery's,
It finally got the better of me and had to have a P38.....replaced engine and roof lining so far..love driving it
1996 gems
so ok, im going to be removing the dash and doing the heater core, orings ect...
What should i replace whilst all this is apart??
i have this fault that wont clear..
(28) LEFT HAND BLOWER MOTOR STOP MODE FAULT.
all advice welcome, i don't want to put it all back together to find i should have replaced this or that..
Thanx in advance
theelms66
25th January 2020, 08:24 PM
When I had a p38 I replaced my heatercore and o rings without removing the dash .can be done.
roverv8
28th January 2020, 04:47 PM
well...it's certainly died off around here....
PeterH
28th January 2020, 06:08 PM
Hi roverv8, yes it certainly has died off around here!
The left hand blower motor stop mode fault is the exact same issue I have at the moment, I'm about to investigate that one.
I came across an interesting you tube video where the blower motors have a relay built in that can get dirty over time and stop the blowers working.
They can be fairly easily removed and cleaned up, I'm going to have a crack at this myself.
YouTube (https://www.youtube.com/watch?v=mjc6H0cDfxQ)
Also check relay RL7 in the fuse box, that is a notorious one for overheating and failing or giving trouble.
The area under the relay where it plugs in can crack and cause hevac issues too.
I've just done the heater core o ring job myself, It's pretty awkward to get at, but I did it without removing the dash, ended up cutting the black plasic ducting that is in the way and that made the job much easier.
There are videos on you tube that are well worth a watch to give you the idea of what to expect.
I'd do a fault code read and see if any other faults pop up, if not I'd just leave it be until you need to get in there and do the blend motors.
Good luck with it!
Hope that is of some help.
prelude
29th January 2020, 06:01 PM
Whilst having the dash out: clean out dust, replace the foam that makes a seal between the heater/cooling core and the dash, do the same for the pipes that you have to disconnect. Clear any dust from the interior temperature assembly (it's a small fan that sucks in air to be measured) and if you want to avoid any problems in the future and are willing to spend the $$ replace the hevac motors since they all go eventually. At least check if they have been replaced recently. Taking the dash out again is a lot of work :)
Also, when you're down there you can take the left and right blower motors out and open up the interior filters from the outside and clean up any crap that has gotten in between over the years. There is an earthing point somewhere under the dash, my memory fails me where exactly but it should be easy to find once the dash is out. Undoing, cleaning and re-tightning is recommended since they do sometimes cause trouble. Our P38's love it when the voltage is exactly right!
I believe that's all I've got for today... If I remember anything, I'll drop a line.
Good luck!
Cheers,
-P
PS yes it has gone quiet. :(
PeterH
31st January 2020, 04:02 PM
Just an update on this thread, I did pull the blower motors out and give them a clean up as per the you tube video posted above.
After reinstalling and clearing the blower motor fault code, I'm pleased to report the air conditioning seems to be working perfecly again.
I actually thought it may have been stuck HEVAC flaps, as there was not much air coming through the vents, until I went over a bump and bam it started working properly.
Anyway, this did work for me, the left side is fairly easy to get at, the hardest part is removing the glove box, the drivers side is a bit more tricky with a cable race in the way.
Good luck with it, hope this helps!
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