Xantia heater issues...

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Mark Graham
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Xantia heater issues...

Post by Mark Graham »

Hi all,

I recently bought a cracking Xantia, 19td sx auto with 48k... I love it but i have a couple of heater issues.

First its either on full or off. I have a good resistor module on the way to hopefully fix this.

Second is I cant get any heat out of the thing. I never noticed this when i bought it as it was warm at the time! (If the heater is off and the heater vents open there is a very small amount of heat coming out)

I have had a complete coolant change done and thermostat replaced as the temp gauge never really got over 75, sits at 85 now.

The matrix pipes are hot. There is no coolant loss and no evidence of leaks in the cabin

When i got the car there was a whining coming from the engine bay that turned out to be the ac compressor, until i get a chance to replace it a belt from a non aircon car has been fitted to bypass it.

Is this likely to be a heater flap issue? If so is something likely to be jammed or do i need to replace them?

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CitroJim
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Re: Xantia heater issues...

Post by CitroJim »

For the first issue tyou say ewither on or off... Do you mean the blower? Is it eiter off or constantly running at top speed? Does it come immediately the ignition is switched on?

If so, a replacement speed control module should fix it...

The second fault sounds like the air mixer flap is indeed stuck. It's an air-blender so the matrix is always hot and has coolant flowing through it... In the cold position the blender flap sits in front of the matrix to effectively shut it off...

The flap is driven by a little stepper motor which can be just glimpsed under the heater box and this stepper motor is under the control of the heater/AC ECU which is a long, thin module that sits to the passenger side of the heater box...

I've never known an ECU fail but I have known the gears 'twixt motor and flap break in one instance but by far the most common reason is a failure of one of the temperature sensor probes making the heater ECU believe the car is always too hot...

The major culprit is the sensor mounted high in the dash next to the clock behind a little grille. Just behind the grille is a tiny fan to blow cabin air across the sensor thermistor... If this fan fails - often due to being bunged up with dust - the sensor detects how hot it is behind the dash and heat coming off the radio and sets the heater accordingly to try and cool things down. hence a cold cabin...

The fan and sensor can be carefully dismantled for cleaning purposes...

Hope that helps a little...

admiral51
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Re: Xantia heater issues...

Post by admiral51 »

Not sure if MK1 and MK2 are the same but you should be able to hear the fan running with the radio off and the blower off, sometimes they are very noisy.
To expand on Jims location of it a bit, it is on the trim panel from the glovebox to the steering wheel, the grill is just a few slits in the panel.
From memory i think i have a heater control module in my spares shed so if a wheel has broken i may have a replacement but will need to double check.
Congrats on picking up a good un, is it Red by any chance :)

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CitroJim
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Re: Xantia heater issues...

Post by CitroJim »

admiral51 wrote:
07 Nov 2020, 18:36
Not sure if MK1 and MK2 are the same but you should be able to hear the fan running with the radio off and the blower off, sometimes they are very noisy.
Mk1 and MK2 sensors are different... And not really easily interchangeable...

If you can't hear it, shining a bright torch through the slits can show if it's spinning or not... You may need to turn the ignition off and back on and start the engine to be sure of what you are seeing...
admiral51 wrote:
07 Nov 2020, 18:36
To expand on Jims location of it a bit, it is on the trim panel from the glovebox to the steering wheel, the grill is just a few slits in the panel.
Thanks Colin, that's appreciated :D I'm working from memory these days and it's not perfect by any means :twisted: :lol:

I really had to think hard where it was at all :roll:

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Re: Xantia heater issues...

Post by admiral51 »

Jim your memory is better than mine and i was just adding padding :rofl2:
MK1 and MK2 i was thinking about the heater panel itself, from memory they are cable driven and have plastic cogs so i think i have one in my spares stash but it would be from a MK2 but not checked all the boxes yet :(

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CitroJim
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Re: Xantia heater issues...

Post by CitroJim »

admiral51 wrote:
07 Nov 2020, 18:48
MK1 and MK2 i was thinking about the heater panel itself, from memory they are cable driven and have plastic cogs so i think i have one in my spares stash but it would be from a MK2 but not checked all the boxes yet :(
Colin, I giggled at that...

Yes, MK1 and MK2 heater panels I'm as sure as I can be are identical :)

The cables drive the recirculation flap and the demister/air direction flaps. Certainly worth checking as the cable inners can become kinked and then are not able to fully operate the flaps...

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Re: Xantia heater issues...

Post by Mark Graham »

xantia and sve.jpg
My photo of my cars, taken by me copyright owned by me

Thanks for the replies, ill get onto it tomorrow. Photo shows the car, and my 605 SVE. Also got a 605 2.1 diesel and just bought a Xantia Activa...

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Re: Xantia heater issues...

Post by admiral51 »

Picture of the grill taken from my car today time can be seen on the clock :rofl2:
DSC_0661.JPG
Last edited by admiral51 on 07 Nov 2020, 18:56, edited 1 time in total.

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CitroJim
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Re: Xantia heater issues...

Post by CitroJim »

Looks good Mark, a nice collection of cars and the Xantia beautifully complements the 605s :D

admiral51
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Re: Xantia heater issues...

Post by admiral51 »

Mark Graham wrote:
07 Nov 2020, 18:54
Image
My photo of my cars, taken by me copyright owned by me

Thanks for the replies, ill get onto it tomorrow. Photo shows the car, and my 605 SVE. Also got a 605 2.1 diesel and just bought a Xantia Activa...
:mrgreen: :mrgreen: :mrgreen:

admiral51
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Re: Xantia heater issues...

Post by admiral51 »

admiral51 wrote:
07 Nov 2020, 18:54
Picture of the grill taken from my car today time can be seen on the clock :rofl2:

Image
Now i have looked at it in situ memory has kicked in, i think that if you remove the radio you can gain access to the rear of the senor/fan assembly, it is much easier than removing the trim panel and i think it is a push fit so will have a tab that need squeezing to remove it but could be wrong :? and you can have it hanging connected to check it works

*** Edit the pic is from a MK2 but still think radio removal will work on a MK1 ***
Colin
Last edited by admiral51 on 07 Nov 2020, 19:08, edited 1 time in total.

Mark Graham
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Re: Xantia heater issues...

Post by Mark Graham »

thank Colin, as luck would have it I already have the radio out to fit a cd player in! Ill check the sensor/fan assembly tomorrow

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Re: Xantia heater issues...

Post by Mark Graham »

CitroJim wrote:
07 Nov 2020, 18:21
For the first issue tyou say ewither on or off... Do you mean the blower? Is it eiter off or constantly running at top speed? Does it come immediately the ignition is switched on?

If so, a replacement speed control module should fix it...
Thanks! Yes, the blower is either on full or off. I ordered a resistor module from ebay and it was rubbish and didnt work at all. Managed to find someone with a good used one with matching numbers and its on the way. Fingers crossed that sorts the first issue!

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xantia_v6
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Re: Xantia heater issues...

Post by xantia_v6 »

If the blower is full-on or full off, controlled by the switch on the heater control panel, then (in addition to a probable faulty speed control module), someone has changed the wiring of the control panel, and that has probably broken the operation of the temperature control system.

Look carefully for signs of cut and spliced wires behind the control panel and around the blower motor. I think that there is more to find before you get this working.

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white exec
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Re: Xantia heater issues...

Post by white exec »

Mark Graham wrote:
07 Nov 2020, 19:23
The blower is either on full or off. I ordered a resistor module from ebay and it was rubbish and didnt work at all. Managed to find someone with a good used one with matching numbers and its on the way. Fingers crossed that sorts the first issue!
This thread (from January 2020) pulled together many of our findings about replacement heater blower modules...
viewtopic.php?p=633501#p633501