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Ptc Heater Operation - Diesel

17K views 55 replies 4 participants last post by  volkerg99 
#1 ·
Hi i have the 2004 1.6 diesel and am wondering if the ptc heater is working or not. It seems to take ages to get hot air in the cabin and usually only gets warm when the temp guage starts to rise.
The manual is a little confusing as it states that the ptc is switched on when engine is cold, the air temp is low and the alternator load is not excessive which makes sense, but it says it will display aux heater xxx% on the dash which i have never seen. Also in the set/reset menu on the dash there is no option but i think this is for the aux heater and not the ptc. The haynes suggest that its switched on when temp is 10 degrees or less and engine less than 60.
There is a 80 amp fuse fitted F5 for the ptc but not fully sure how it works. Is it on/off or pwm controlled? Since its in the centre console its a big job plus i can only check it whens its cold. Anyone had any experience?
 
#5 ·
Ok - So a little confused now. Rang Ford for a quote on a new PTC heater and they seem to think that my vehicle is not fitted with one, but werent 100% sure. I have only had the vehcile less than a year, so dont know either. Re-checked the handbook and its states its country dependant... Taking the facia off to have a look is going to be a lot of work. Has anyone got a 1.6 TCDi 2004 C-Max with known PTC Heater fitted or was the UK an optional extra?
 
#7 ·
Thought I would provide an update as nothing more annoying than reading a thread with no final result. Took the lower dash out of the car to have a look. Followed the wires from fuse box in engine through to hvac and found the connectors placed under the passengers mat. There appears to be no place for a ptc in the hvac and the hvac label states a/c only. Therefore it would appear that a different hvac unit is needed to support a ptc heater and this would not be economical option.
 
#8 ·
Thanks for the update.

Its shame the PTC isnt fitted to all models, perhaps including the petrol's as it works a dream when its cool. Definitely gets up to 60 degrees input air and approaching 20 degrees within a couple of minutes when there's ice on the screen. Looking at the fuse rating on the Mondeo the PTC could be upwards of half a kilowatt peak load
 
#9 ·
Hi,

I have to retract my previous comments about the HVAC - There is a place for the PTC heater - I was looking on the wrong side! The picture I saw in the Ford garage whilst looking for the part on their system shows it above the fan / air in take, but it is actually near the floor just above the heater matrix (as apposed to the A/C evapourator). There is a small control type connector just near the module cover that is not used.

I will do some more digging in to what it would take to fit one and what needs to change on the car (SW maybe, coding change etc) to make it work. Will keep you posted!

Regarding the power - Its connected to an 80A fuse on the C-Max

Best Regards, Paul.
 
#10 ·
That could be an interesting project Paul and one that I'm sure others would be interested in if you can install the PTC, plug it in and get then firmware upgraded.

Yes it's a 80A fuse on the Mondeo too, and I was working on say a mean current pulsed through the PTC of 50-60 amps or so to give over half a kilowatt.
 
#11 ·
Had a chat with the local Ford dealer to see if this is possible or not. To be honest i dont think I gain much from this, except that they were not able to offer this service as such. i am not sure they really knew what would be involved and perhaps PTC heaters are something they dont often get involved with. I have tried online parts websites to see if I can obtain a second and PTC heater to play with, but not had any joy as yet.

Looking on the internet I found this... http://www.golfmkv.com/forums/showthread.php?t=113468 This shows how to retrofit a PTC in a Golf pretty much as I am proposing fo the C-Max. Now the interesting parts on this... The PTC heater is CAN controlled and only has direct battery connection. This would kind of fit in what I have seen on the C-Max so far that the wiring looks direct from the battery and the car can control the amount of power the PTC heater delivers. Therefore the CAN interface would be a good way to do this and may be the same.

The Golf needs the coding changes using the VAG tools to turn on the PTC heater options. I am not too familiar with what is available on the Ford tool side. Does anyone have any ideas? I am more familar with the hardware side of things. What I have read so far is that GEM controls the PTC heater, I am guessing on the low speed CAN bus. There must have to be some coding changes required, but whether there is any other hardware bits needed I am not sure yet. Any feedback from anyone would be appricated.
 
#12 ·
Well that doesn't surprise me regards the dealer not understanding what was involved, possibly on 2 counts, one they not be interested and the other they may be interested but cant really get the opportunity to fulfil their curiosity on a car, particularly a customers.

Yes the heater is connected directly to the battery via that 80amp fuse (one of the things I wondered was the cause of flat batteries on Mondeos). Looking at some drawing someone loaned me, the heating control is provided by a PWM signal from the central control box which of course is adjacent to the heater when in the car in the Mondeo.

The control connector may be the electronic supply and PWM connections if there are only 2 cables there. Pity its not cool as you could put a scope or even a decent digital meter on the connections and see if one has power and the other has a PWM pulse on there. If it did find there were active your part way there Paul. You just need what looks like 10mm csa cables to the heater power connections and your away.
 
#13 ·
Regarding the power cables the 80a fuse and power loom to the hvac is already fitted in the vehicle. Will have to look in more detail at the possible comms connector to see whats there in terms of wires etc not that easy to see as the lower dash does not come away fully with out removing the handbrake to gain enough room. Can get a scope on it when its cold if required to really see if anything is there.
 
#18 ·
Another thought - anyone know where the outside temperature sensor is? I can then make a fake low outside temp and that way I wont have to work in the freezing cold!

Also was reading about the Galaxy - apparently they have the full on Diesel operate Aux heater that burns diesel to heat the in cabin and this is standard fit to all vehicles. This is an option on the C-Max as well according to the manual. Not sure of the Galaxy has the electric element or not as well.
 
#19 ·
Small update: Can confirm that there are only two wires to the PTC heater on the control side. These are "Ign" feed and the other must be some sort of "control" signal. Its definetly not CAN. Therefore it might be the case of a PWM signal as suggested....

Have managed to rig up a few wires out of the hvac area into the car with some pull up resistors and LEDs attached (much easier to work this way). Currently have the two PTC control lines and a ground wire routed out. I have a red LED between the "Ign" feed line and ground, this comes on with ignition. The Green LED so far goes between the control signal and ground. It currently does not do anything and there is no real voltage to see there. I shall wait until its cold (it was the other morning 7 Deg C) and see whether anything happens on the green side. One thought I had is that I dont know if the control signal is actively driven or if low side drive only. Therefore may add a pull up between "ign" and the "control" to see if this makes any difference.
 
#20 · (Edited by Moderator)
Yes I suspect its just a PWM signal that is there when the temperatuer is cold enough.

You could always use a red and green LED and with a 4.7k in series with each LED then connect the 2 LEDs and resistors in series and connect across 12V, then connect the PWM signal to the center of the 2 LED circuits. You can leave it connected up for the sudden cold morning and should give you an indication then of whether its source or sink (pull up pull down) providing its not a high impedence signal.
 
#21 ·
Good idea from Phil - Thanks. Haven't had time to try this out yet. It gets dark so quickly in the evenings now.

It was 7 Deg C this morning, nothing showed up on my green LED, but I have yet to add the 2 LED idea to give a pull up as suggested. So it either does not work or does not give out any voltage on the signal line.

Will keep you posted after I have tried the 2 LEDs.
 
#24 ·
Hi, sorry for the delay but have been busy and there has not been many opportunities to test when its cold!
What I have learnt so far...
The signal wire checks out about 90k Ohms to ground. The LED is between ign and the signal wire now with 10k. It just about lights the LED, but that is through the 90k resistor in the GEM.
Seems not to do anything active when its been 8 Deg C the other day

The other thing I have discovered is that there is a signal wire from the heater controls to the GEM, which indicates that the hot setting has been selected. This should instruct the GEM to activate the PTC heater if the conditions are right. Have looked at this signal and it does not do anything. The wire is connected to the GEM, but I need to trace it through to the heater control to see why it does not change. This is a bigger job as need to remove the radio etc. Will update when I get time to look at this.

Paul.
 
#25 ·
Thanks for the update.

So the signal wire looks like a sink though 90k does seem high.

Mmm the 90k impedance may feed a high impedance input of course on the PTC heater and while the LED may not seem to change, the PWM may when conditions are correct, though may not be noticeable on the LED.

Interesting the additional wire. Hot setting, not sure what you mean there.

When you've got this going (and I hope you do), you could go a step further.

One day last winter (I've tried to find my original post on the forum) I tried an additional PTC heater in the rear of the Mondeo to see how it assisted defrosting the iced up rear side windows. I actually used 2 x 150W PTC heaters sat in the rear footwell and was surprised how quickly they cleared and how quickly the car heated up. I didn't have any temperature control on this particular test so it actually got a bit too warm so had to simply disconnect the power, which was a feed from the rear junction box in the boot where there is a permanent live and an ignition live.

Well this summer I've fitted the heaters under the front seats and they sit in what is a convenient 'well' in the floor pan under each front seat.

The power is taken from the supply in the boot that would be used for the heated rear seats, this then goes to a small temperature controller I've put together, which has a 30 amp relay controlled by the temperature control and can be set between 0 and 30 degrees. I have it set to around 8 degrees. The controller is located in the side of the boot behind the boot trim and the temperature sensor is located just under the front lip of the middle of rear seat (hidden under the seat is the adjustable pot to set temperature). From the controller I have fed each heater individually via a 10 amp fuse with 4mm CSA tri-rated cable to keep the volt drop down and hidden under the floor trim. The sensor has mounted with it a pair of LEDs which show power on and also when the heaters are powered. One day last week and this morning they operated and I could clearly tell they were on by putting my hand down to the rear footwell as well as the tell tale LED. Now I'm looking forward to the cold frosty mornings to see how they perform. Should also benefit the rear seat passengers of course until the heat starts coming through the rear ducts.
 
#26 ·
This sounds pretty cool mod. I am impressed, defrosting the car should be quick. I wonder how much current you draw with the main PTC on and the additional ones? Does the Mondeo have a 150 alternator?

Regarding the extra wire - probably did not explain too well. From what I understand there are two heater control variants, High spec - climate control or what I have low spec manual climate control. When the heat setting is set to hot rather than cold, there is a signal from the heater control panel to the GEM to tell it switch on the AUX heating. I guess this is to ensure that the PTC will have some air flow over it before switching on. This is the additional wire on the low spec, but is sent over CAN on the high spec model. I have traced it to the GEM so far, but need to find whats on the other end as when I looked at this with my son, the signal never changed no matter what the heat setting was on. I am wondering if there are different variants of the control panel for vehicles with and without AUX heating. When I get time to take out the radio and front facia I will have a look at whats connected to the controls and report back. I dont know if its expecting an analogue pot type input or a switched one. One thought was that I could always add this as a fairly simple mod if its not fitted and is required. There is even a switch space below the rear window demister and front screen window heater buttons where another button could be added.
 
#27 ·
So the wire isnt part of the MAX button on the high spec is it, does your model have a MAX button for demisting the interior quickly?

The additional PTCs only draw 10 amp each. The heated rear seat circuits if I had heated rear seats are fuse protected at 15amp each. I will say that I have a digital voltmeter in the car permanently connected on the battery saver and even with everything on (I mean everything on), dip, main fogs, heated screen and rear window and front heated seats and climate/heater fan running the voltage doesn't drop below 14.0V though its usually up between 14.5 and 14.9V, the higher value just after I've started the car.

PTC in the heater was on this morning, as were my additional ones as I moved the car.
 
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