Heater: 70: All sorts of C70 Problems Aircon/Heater/Heated Seats

[bobsteel]

Have had a bunch of issues and they all SEEM unrelated, but just a bit odd.

The A/C had been failing and after a bunch of troubleshooting, i found it was the low pressor sensor. Replaced that and it works a treat. But now, coincidentally, I've found both the heated front seats no longer warm up and the blower fan despite being set to MAX, does not create any heat.

I suppose it could be a thermostat issue on the heater but the seats seem to be fine fuse-wise and there's no other electrical answer I can think of. Is there another ECU sensor that would make the seats not function? I've tried resetting the CCU by removing the battery leads and jumping them in ignition position II, but no luck.

Baffled by this sequence of problems as can't really recall a situation where I don't get any heat in a car despite fan blowing on full tilt!

Anyone have ideas?

Many thanks

[Dippydog]

Is there a heater bypass valve on these?

[Luxobarge]

Originally Posted by Dippydog

Is there a heater bypass valve on these?

Quick answer - no.

[bobsteel]

is there a temperature sensor that could be failing? i looked for a small grate where a sensor would be based on other models but i don't see one. is there a sensor in the mirror as other models might have? just feels odd that these systems would fail together.
also, possibly related, the clock no longer works after I did the CCM reset. no idea but i might just have a fuse issue there.

cheers

[ITSv40]

As far as I am aware there are three temperate sensors.

A solar sensor on the top of the dash in the centre by the windscreen, it is combined with the alarm sensor.

An interior temp sensor behind a little grille on the left hand side of the switch panel on the dash - left hand side of the steering wheel.

A heater duct temperature sensor in the heater ducting and located by the blower motor. Not sure how you get in to it, but guess it will need some dismantling.

Am I reading your posting correctly, in as much that you can get cold air with the aircon on, but no warm air when set to heater setting, even with the blower on full. Are both sides of the car showing the same symptoms?

[Stumo]

Does that light sensor in the alarm pyramid thingy have anything to do with the climate system? Purely from what I’ve seen and experienced with it, it is when you have the alarm ‘chirp’ confirmation activated, it doesn’t chirp at night. (Part of the dealer set up)
It wouldn’t surprise me it’s involved with the ECC. I assumed the ECC used the temp sensor in the dash and the ambient sensor in front bumper, although there is a listed error code talking about passenger temp sensor ( possibly in the control box itself maybe)
I’m keen to know more if anyone knows...

[ITSv40]

It may be different in NZ, but the UK spec has a solar sensor on the dash to determine whether or not the car will heat up with solar gain. The description in the handbook explains how the system takes into account air speed/humidity, solar gain, inside temp and the setting selected by the driver to work out how much cooling/heating is needed and at what speed to run the fan to gain the quickest result. There is also a note: Do not place anything over the solar sensor on the top of the instrument panel as this will cause the climate unit to receive incorrect information.

My V40 a similar age with climate, has a similar reference in the handbook. The solar sensor in that is also similar to the C70 with the alarm led in the centre of it.

[bobsteel]

Originally Posted by ITSv40

As far as I am aware there are three temperate sensors.

A solar sensor on the top of the dash in the centre by the windscreen, it is combined with the alarm sensor.

An interior temp sensor behind a little grille on the left hand side of the switch panel on the dash - left hand side of the steering wheel.

A heater duct temperature sensor in the heater ducting and located by the blower motor. Not sure how you get in to it, but guess it will need some dismantling.

Am I reading your posting correctly, in as much that you can get cold air with the aircon on, but no warm air when set to heater setting, even with the blower on full. Are both sides of the car showing the same symptoms?

Yep the cold air works fine but no warm air in any vent. Both sides exactly the same.

[Dippydog]

As there's no heater bypass valve on these there must be some way-flaps?- of stopping you getting heat when cold is selected or vice versa.I don't know if this system would be operated by rods/linkages or electrically but is it/are they functioning correctly?If you cannot physically see them you should by listening very carefully here it/them moving as the temperature selector is operated.

[bobsteel]

Originally Posted by bobsteel

Yep the cold air works fine but no warm air in any vent. Both sides exactly the same.

Also I tried vacuuming out the small interior temperature sensor but didn't seem to make a difference :/