Intermittent Problems - Oh the joys.......

Ok, I have mentioned on here before that I have the book symbol on my HEVAC unit. On starting, and for the first 40 or so fast miles (explanation later, look for the '*'), my unit only blows hot air no matter what the temperature (unless on LO) with the AIRCON turned off. Other info, the 'air' only blows onto the windscreen no matter what happens and the book symbol stays no matter what.

*After 40 or so motorway speed type miles, still with the AIRCON turned off, 16 becomes 16, 20, 20 and so on. Then, after 20 or so slower miles it reverts back to everything over LO be ON and LO being road temperature (Quite cold about now).

Now, I also have an intermittent fault with the rear drivers side tail light that has only started to occur recently. Notably the lens cover has always (since I have had it) had a 2 inch hole in it towards the bottom on the side facing the tailgate. Overnight the fault appears in the morning and again if you do not go above 50 for more than 10 minutes or until later in the day it remains and warns on power down. But for some reason later in the day or after some good running in, the fault cures itself and the bulb works again. Could this be condensation on a cold night leaking into the bulb socket and disrupting the power supply, but after the whole car has warmed it dries out? Any ideas?

Many thanks

Adam

*BUMP*

Anyone help at all?

Hi.

Have read your post and am having a little trouble understanding the symptoms......you know that the book means get it plugged in and find out what the car thinks is wrong...that would be the first step as they do kinda like a function test when you turn the ignition to make sure all the blender motors go from hot to cold etc (you can hear it doing this if you don't start the car)...so somthing is poorly.
The rear light needs to be checked to make sure the contacts are clean inside.....try putting some tape across it overnight once it has been cleaned and see what happens.

Nick.

Hi Nick

Thanks for that, too tight to take it to the stealers right away, anyway.

I thought from the diagnosis advice on the rangerovers.net page dealing with HEVAC, my Blend Motor for moving the flap is knackered and the flap stuck, and the Blend Motor for the temperature regulation hence LO = cold, anything over = hot. But bearing in mind the symptoms and the fact the blend motors are phyical motors with gearing etc. It shouldn't be possible for blend motor (temp reg) to fix itself while running to my understanding?!?!?

Have taped over the light and it seems fine except for one occasion, the crack is better described as a long hole varying in width from 1mm up to 12 mm (roughly) toward the bottom of the light.

Thanks for the reply.

Adam

Hi, just had my 2001 P38 in to deal with the hot air on driver's side plus cold air on passenger (and yes the little book symbol was showing). Garage diagnosed blender motor problem, removed the centre console and dashboard and said it was fixed. Well its not, you can get hot on the passenger side when set to High only and a lot of very cold air blowing very fast when set to Lo. Thank goodness for heated seats. Have given independent garage one last chance to get this right. By the way is your temp gauge reading normal throughout all of this (mine is registering very cold constantly and I'm sure this must be contributing if the thermostat is stuck open?)

I had the same problem with mine - changed the blend motors and it seemed ok for a while then started again - open book, blowing hot one side no matter what, then blowing cold no matter what temp was set at. Then changed HEVAC head unit - no more problems for a while...then it started all over, checked head unit and a connector had slipped partly off. All ok now touch wood, working as it should. If you know its not the blends , try to swop out the HEVAC head unit with a known workig one to test first as they are expensive, even used. A Faultmate / Rovacom reading would help a lot to diagnose the problem - also you need to calibrate the blends and you have to have the software 9Faultmate etc) to do that. Irishrover knows a lot about the set up - PM him on here I'm sure he'll be able to help!

Thanks for that all.

I have looked at RangeRovers.net and the shortcuts to installing the blend motors look v good but my indi refuses to use them and goes by the manual. Should I find a local 4x4 specialist who at least is used to dealing with these machines and would consider the short cuts there?

The most maddening thing is the intermittant nature of it, how the hell can that be possible unless something stupid like wiring expands in the heat and connects a non-broken motor up?!?!?

Anyone with any other thoughts?

Adam

adamrharding said:

Thanks for that all.

I have looked at RangeRovers.net and the shortcuts to installing the blend motors look v good but my indi refuses to use them and goes by the manual. Should I find a local 4x4 specialist who at least is used to dealing with these machines and would consider the short cuts there?

The most maddening thing is the intermittant nature of it, how the hell can that be possible unless something stupid like wiring expands in the heat and connects a non-broken motor up?!?!?

Anyone with any other thoughts?

Adam

Click to expand...

As Rangiegal say's, HEVAC head unit, or bad connections would be a good place to start

There's a chap who does mobile repairs who does three brand new blends within 3 hours or so total for a fraction of the stealers price - I have his phone number, PM me if you want it. I've been happy with his work, but he doesn't have a Rovacom / Faultmate so you will need to have the blends recalibrated once they have been installed to save yourself a lot of grief while they "selfcalibrate" for the next 500 starts or whatever RAVE says. The shortcut is perfectly ok - your indi is obviously clueless as to how to do it that way as no-one would willingly remove the entire dashboard unless they were stircrazy or wanted to rush you for loads of money!!!!

I am thinking that I get quote from the mobile guy, and a further afield 4x4 specialist not my local indie. Move forward from there.

Thanks to everyone, will check out the HEVAC unit.

OK

Money too tight to get the HEVAC sorted, but due to BeCM problem disconnected the battery for 10 (well 30) minutes and reconnected and reset everything. Since then the book symbol disappears with Air Con off, air now will blow anywhere from windscreen to feet.

Put air con on and after a few minutes driving the book symbol comes up. Switch then engine off and back on and it disappears again. Would now guess head unit is fine but air con is knackered. Anyone want to second my opinion?

Adam

with the air con light off, your air con is on. i would think you need a regas..

Yep aircon regas needed but that is probably due to the condensor leaking!

Thanks J and Datatek

Will see if Kwikfit still have that offer on.....

After the transfer box saga gets sorted anyway.

Thanks again

I get that issue in the winter intermittently (only hot air to the screen withthe book symbol).

Pretty sure it's the flap itself jamming - apparently it's slightly too big for the heater and as things expand and contract due to different weather conditions the flap can stick causing what the hevac thinks is a seized blend motor.

If you look on the rangerovers.net p38 forum there is a bodge involving the insertion of a big self tapping screw to expand the heater box slightly. I've not tried it myself yet but it sounds reasonable.

I too suddenly find myself with a constant checkbook symbol although all the blends are working so I think it's a refrigerant leak on mine. So a different problem (probably caused by my messing with the aircon compressor at the weekend)

A regas at slow fit won't spot a pinhole leak in the condensor as it will work for a couple of hours....

Hope that helps.

Guy

Cheers Guy

Will bear that in mind but if it is no cool air no fee, won't hurt to giver it a try....well, maybe

adamrharding said:

Cheers Guy

Will bear that in mind but if it is no cool air no fee, won't hurt to giver it a try....well, maybe

Click to expand...

I had mine done there last year. It lasted 2 hours! So enough for them to charge me (and to be fair it was working when I collected it). My problem is the compressor clutch just doesn't engage all the time. I think I've still got refrigerant in there - I'll test it at the weekend.

I tried taking the washer out from behind the compresor clutch to reduce the clearance at the weekend. It didn't solve the problem and now I have the check book symbol although I'm not entirely sure why.

My theory is that it is the flaps jamming that causes the blends to eventually break (the gears in them anyway). Good ole LR quality control.

Guy

After reading these reprts about A/C Unit I thought I might chip in and ask if any one can help with my A/C fault, starts of ok when engine is cold, then after a while during it goes from cold air to hot air, but if I kick-down and bring the revs up to 4000 then it kicks in cold again and at the moment it's 40c & 92% Humidity here. Any solutions or recommendations Guys?

After reading these reprts about A/C Unit I thought I might chip in and ask if any one can help with my A/C fault, starts of ok when engine is cold, then after a while during a run it goes from cold air to hot air, but if I kick-down and bring the revs up to 4000 then it kicks in cold again and at the moment it's 40c & 92% Humidity here. Any solutions or recommendations Guys?

lac500 said:

After reading these reprts about A/C Unit I thought I might chip in and ask if any one can help with my A/C fault, starts of ok when engine is cold, then after a while during a run it goes from cold air to hot air, but if I kick-down and bring the revs up to 4000 then it kicks in cold again and at the moment it's 40c & 92% Humidity here. Any solutions or recommendations Guys?

Click to expand...

Next time it stops blowing cold air, open the bonnet and see if the compressor clutch is turning. With the air con on and the engine running, the whole pulley should be rotating. If the centre of the pulley is stationary then that's why you're getting warm air.

It might be that your clutch is just starting to wear and slips as it gets hot.

Guy