Not blowing hot

Hello

I bought my 1995 4.0 se about 4 weeks ago, with the usual amount of problems. I am slowly getting there, but i'm having a problem with the heater at the moment. I have checked as much of the posts as i can find, so sorry if i'm repeating. I had a problem with the heater not blowing hot. air con works fine, but i'd thought i'd check it out before winter. As soon as you run the temperature up on the control unit to high, it would only blow luke warm air and the book symbol would come on. When i tried turning the temperature down again, only the drivers side would be cold, but passenger side would still be luke warm. Anyway cut a long story short, got the guy off of ebay to replace the blend motors, no book sign anymore, but heater still won't blow out hot, although, both sides come back down to cold. Both heater matrix pipes are red hot, so there isn't an air lock. Any suggestions?

Thanks
Kev

Have a look at fuses 8 and 17 under the bonnet, the workshop manual states they these would cause either only hot or only cold air if they are blown. As you have had thre Blend Motors replaced it's probably not these. I take it the motors were calibrated after they were done???

Hi

well, yes and No!! The guy that came out, said you could do it manually on the Hevac control unit. He does a lot of these (also members on here) and seems to have a good reputation. I'm beginning to think you do have to get them calibrated with a laptop. Is there a manual way of doing it?

Thanks
Kev

Hi Kev

Not that I am aware of as the motors need to be forced through their full range of movement to calibrate them, which can't be done with the buttons as the motors will only move through what they think is the full movement. It needs software to make sure they move fully.

Hi Nidjet

Thanks. The car is going in to the garage in a week or two, so i'll see if they can do it then. BTW, i did check the 8 and 17 fuses. I presume you mean the ones under the drivers seat and not in the engine bay?

Thanks
Kev

Sorry Kev, I did mean under the seat yes, I was thinking about something else. Good luck and let us know how you get on.

Thanks Nidjet, will do!

I also had my Rangies blends done by Jason and the HEVAC unit started playing up after that - some people DO say they should be recalibrated with software after replacing, which mine weren't - however, after changing HEVAC unit the problem appears to have gone away , at least in recent weeks and the aircon is fantastic again!!! Oh how wonderful a P38 is when its in almost perfect working order!!!!!

I will however, take up an opportunity to get Irish Rover to do a Rovacom analysis when he's over, either this time or the next!

its the blend motors, one or more have failed and require repair or replacement!

gavbriggs said:

its the blend motors, one or more have failed and require repair or replacement!

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The blends have been replaced Gav more likely HEVAC now?

Hi

I will try calibration first. My garage isn't sure they can do it until they have the car. the stealers want £73.60!!! Just out of interest is there anybody in and around the Nottingham area, that has the equipment to do the calibration for a few £££'s?

Thanks Kev

Hello all

well i still haven't managed to get the Hevac calibrated, but the heaters seem to work a bit better now, certainly on the "HI" setting anyway. I have also found out (according to Rave), that the Hevac unit will eventually self-calibrate, depending on how many times you have started the car, but the gap seems to get longer and longer, but it will eventually do it. Thought i would share!!

Kev

Might be worth checking the pollen filters. Cheap fix if they're bunged up. I had a very weak and lukewarm heater until I took out the pollen filters and found them thick with crud. Also the area behind the filters was full of leaves. All this means the blowers are trying to suck in air, but are severely obstructed and can't push out much air into the cabin. Loads of pollen filters on ebay for a few quid. One each side on the top of the bulkhead in the engine bay and easy to change. Couple of screws holding the plastic cover. Once removed, the filter just pulls out. As easy or easier than changing an air filter. Might not be this, but worth a look at the filters which will cost you nothing if they're ok.

Hi mirrorsignalswerve!

I actually replaced them before i found out i had a problem with the heater. They were absolutely s**t up and caked in crap, god knows when they were last changed. but thanks for the advice. the car is due into the garage next Tuesday, so i will see about the calibration.

Kev

Hello all

Just thought i would give a final update. Took car to the garage, but they didn't have the equipment to calibrate the Blend motors. Read again on "Rave", to double check what needed to be done. Did a 100 "starts" on the car yesterday and went down this morning to do as many as i could before work (i was aiming for a total of 500, as this is the gap between self-calibration), just got over 50 and hey presto, the blowers stopped working and i could hear the blend motor flaps moving up and down..hooray!! The whole process only took about 10 seconds and the dealer was going to charge me £73.80 for doing that, what a rip-off!!!

Kev

Hi you was talking about 100 starts.? Can you explain??

c099895 said:

Hi you was talking about 100 starts.? Can you explain??

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Switching the car on and off 100 times

When changing the blends you need to calibrate them via the software. If you don't, they self calibrate according to RAVE after a few hundred starts.

Hi Rangiegal.....I'm over now, PM me if you want to. Over next around 17th Dec..back early Jan. 2010.

Yes, definately need the blend motors calibrated after replacement despite what you have read on here. They have to be "Taught" the open and closed positions in order that the HEVAC knows the values and can calculate the positions in between to give the correct temperature. If the HEVAC sees unknown values it will throw up the "Cheque Book" symbol.
Calibration takes all of 15 minutes to do and is starightforward. Find it hard to believe that someone who is adept at changing the blends has not got the software to complete the job properly and calibrate them.

I guess its hard times out there for many...an outlay of over £2000 may just be too much for a one man band at present.

Irish, I'm in Norfolk on a contract so may miss you this time around will the Faultmate kit do the job as well? I may have the opportunity to buy one soon if its worth having.....

Hi Laurie...no problem. Faultmate is the later version of Rovacomlite hardware and will do the job. The HEVAC software package is around £100 from memory.
The stealers are probably charging you 1 hour flat rate for a few minutes work. You have to allow for a tea break:tea: and a couple of smokes:smokin::smokin:

Hopefully the garage is not too close to the boozer:beer2::beer2::beer2::beer2::beer2: