Heater Problem
Discussion
Searched the old posts for this but can't get a definite idea of how the heating system works.
I'm only getting cold air blowing through in my 2001 Mk1 Tuscan. Fan works ok, and when I change the temperature the air stops, then the clunk (as something? moves) and the air starts again ... but always cold !
How does the system work, and what's the order I should check things in (and what to look for). Any help much appreciated.
I'm only getting cold air blowing through in my 2001 Mk1 Tuscan. Fan works ok, and when I change the temperature the air stops, then the clunk (as something? moves) and the air starts again ... but always cold !
How does the system work, and what's the order I should check things in (and what to look for). Any help much appreciated.
I have the exact same problem. (2002 model) I've had the bonnet, wipers, scuttle panel etc off as per one thread stated, but wasn't sure where to go from there once I was faced with hacking sealent off from the foil covered thing?? which is where I presume the offending stepper motor lives??
HELP!!!!!!
HELP!!!!!!
RWA28 said:
I have the exact same problem. (2002 model) I've had the bonnet, wipers, scuttle panel etc off as per one thread stated, but wasn't sure where to go from there once I was faced with hacking sealent off from the foil covered thing?? which is where I presume the offending stepper motor lives??
HELP!!!!!!
me too, thats as far as I got, and not had a chance to have another go, I must buy some black silicon or silkaflex or whatever the sealant is. I'm hoping it's just a loose grub screw as my stepper motor is quite new.HELP!!!!!!
What's the stepper motor for ? And any info on how the heating system works, what it's made up of and what could be failing ?
Also, air con ... if I press the temperature button I get the little blue light, does that mean i've got air con, or does that happen on all cars regardless ? I thought I had it in the car, but doesn't seem to work either !
Also, air con ... if I press the temperature button I get the little blue light, does that mean i've got air con, or does that happen on all cars regardless ? I thought I had it in the car, but doesn't seem to work either !
Don't rule out the fact that it's not working. My trinary switch (controls the radiator cooling fans and air con) was duff and it meant I also wasn't hearing the clunk. New trinary switch, repressure the system, bingo!
Ref the heater - never had mine apart (well engine bay bit anyway!!)
Ref the heater - never had mine apart (well engine bay bit anyway!!)
Anyone give any pointers what to look for to see if air con is fitted ? Any pics ?
Heater problem is more pressing though. I take it the system works by letting the hot water into the heater matrix .. so does the stepper motor regulate the flow of that water into there ? I'm assuming it's stuck shut so no hot water is flowing ? If that's the case, where does it live, is it repairable, or does it need replaced ? Could it be a problem with the heater matrix (and again, where does that sit) ?
Help much appreciated.
Heater problem is more pressing though. I take it the system works by letting the hot water into the heater matrix .. so does the stepper motor regulate the flow of that water into there ? I'm assuming it's stuck shut so no hot water is flowing ? If that's the case, where does it live, is it repairable, or does it need replaced ? Could it be a problem with the heater matrix (and again, where does that sit) ?
Help much appreciated.
JET, All of what I am about to say is caveated by 'It's like this on my car', rahter than 'They are all like this'.
I don't know how the water is regulated, but under your dash, there are 2 pipes (about 3" dia). One has hot air and the other has cold air (with a smaller hose coming into it which does the driver sterrign column air I think). Your heater control changes which pipe has fan air blowing from it. I'm guessing it moves the stepper motor which controls some sort of deflection vane. From memory, the hot air is the right hand pipe (as you sit in the car) and the cold is the left. With the heater control on fully hot, all the air comes from the hot pipe, turn 1 led left (ie toward cold) and you then get air from the both pipes until when it is on fully cold and thei air only flows from the cold pipe. I have my actual 'measurements' at home, not here, so I might be able to post them later (if I can find them). This might be of help, it might not. Do a search for info on how to get the dash off.
I don't know how the water is regulated, but under your dash, there are 2 pipes (about 3" dia). One has hot air and the other has cold air (with a smaller hose coming into it which does the driver sterrign column air I think). Your heater control changes which pipe has fan air blowing from it. I'm guessing it moves the stepper motor which controls some sort of deflection vane. From memory, the hot air is the right hand pipe (as you sit in the car) and the cold is the left. With the heater control on fully hot, all the air comes from the hot pipe, turn 1 led left (ie toward cold) and you then get air from the both pipes until when it is on fully cold and thei air only flows from the cold pipe. I have my actual 'measurements' at home, not here, so I might be able to post them later (if I can find them). This might be of help, it might not. Do a search for info on how to get the dash off.
S6PNJ said:
Don't rule out the fact that it's not working. My trinary switch (controls the radiator cooling fans and air con) was duff and it meant I also wasn't hearing the clunk. New trinary switch, repressure the system, bingo!
Ref the heater - never had mine apart (well engine bay bit anyway!!)
Where is this "trinary switch"?Ref the heater - never had mine apart (well engine bay bit anyway!!)
My 2001 is the same.. popped it into the indi the otherday and tested the control box.. that was faulty first.. then put one on from another car to eliminate it and found the stepper motor isnt working as he said you can hear it with just the ign on when you turn from hot to cold or cold to hot and mine was silent so he said its def that.
He said they are prone to stipping the teeth. He said you can pick a second hand one up from a breakers for around 50 notes. He also said its not an easy job. So im sourcing the parts and booking it in for them to do. But if anyone has a pic of a stepper motor i would appreciate it as the breaker has asked me for one and im struggling to find a pic.
Sam
He said they are prone to stipping the teeth. He said you can pick a second hand one up from a breakers for around 50 notes. He also said its not an easy job. So im sourcing the parts and booking it in for them to do. But if anyone has a pic of a stepper motor i would appreciate it as the breaker has asked me for one and im struggling to find a pic.
Sam
I had the same problem on mine a few months back and it was the stepper motor that had gone! Was a right arse of a job to be honest, really fiddly and took me a good few hours. As people have said its located in the box in the engine bay next to the exhaust manifold. The hardest bit is getting this box out as mine was tiger sealed in!
Basically the heater matrix (like a little radiator) lives in that box, hot water from the engine is pumped through this radiator (you will see two pipes going into it from the engine - a feed and a return) Also at the bottom of this box is a flap and a hole - when you turn the heater in the car to cold, the stepper motor moves this flap to the open position so cold air is fed from the hole (from outside the car). When you turn the heater in the car to hot the flap closes and seals the box so you get the heat from the matrix. What happened on mine was that the little electric stepper motor got weak and didnt have the power to lift the flap shut so it was always cold. Sorry if that sounds really basic as I know a lot of you guys know your stuff but until I took this to bits I didnt know what to expect. My diagram may be a bit off as it was ages since I did this but it will give you an idea!
Cheers
Stu
Basically the heater matrix (like a little radiator) lives in that box, hot water from the engine is pumped through this radiator (you will see two pipes going into it from the engine - a feed and a return) Also at the bottom of this box is a flap and a hole - when you turn the heater in the car to cold, the stepper motor moves this flap to the open position so cold air is fed from the hole (from outside the car). When you turn the heater in the car to hot the flap closes and seals the box so you get the heat from the matrix. What happened on mine was that the little electric stepper motor got weak and didnt have the power to lift the flap shut so it was always cold. Sorry if that sounds really basic as I know a lot of you guys know your stuff but until I took this to bits I didnt know what to expect. My diagram may be a bit off as it was ages since I did this but it will give you an idea!
Cheers
Stu
Edited by Prodrive on Friday 15th February 10:47
Pleased it was of some help.
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