Help! Sporadic temperature glitch - duct problem?

[blackflash]

A fault has occured once for a short period a couple of days ago and today (Sunday) for over an hour though eventually seemed to sort itself. It did not occur at all on a 450-mile round trip on Tuesday or before that or between the above two events.

When it goes wrong, cold air is being blown into the car. With everything set to Auto, if I increase the temperature setting from say 21 to 24 then the fan speed increases as you'd expect as it tries to hit the new target temperature - but the air being blown in is cold. If I turn the setting down then the fan speed drops, so the "intelligent" aspect of the whole set-up seems to be working. This leads me to believe that the temperature detector inside the car is working correctly and the system's brain is thinking straight...

It must be that it is drawing in different temperature air from what it thinks it is. My guess is that a duct is disconnected at one end or loose somewhere. If it was split open or completely detached then it would not have occasionally worked eg. for the last 15 minutes of my last 45 minute journey.

Does this sound like a decent starting point for investigation? If so, how easy is it to get to the ducts to check them?

Thanks in advance for any help. I can see I need to get myself a workshop manual...

Nigel

[blackflash]

HA Fox main dealer took just over an hour to diagnose heater pump failure by plugging in a donor one. They then confessed that they had knocked the existing one in removing the donor (which had not been fully fitted by the way, that's a longer job) and behold, it started working again.

They suggested that, given that a new unit is £450 (not sure whether that is fitted cost or plus labour but it's not cheap!) why don't I run the car until the unit fails and bring it back in. How much for this advice and one hour's labour? Nil. Nice people.

I then spotted a reconditioned unit on eBay and bought from Eurojags at around £60+VAT plus £20 I get back when I send in my old unit. Damned nice people to deal with, unit arrived next day and will sit and wait until existing fails... I though it was worth investing now rather than hunting around when I desperately need one.

I spoke separately to Eurojags about another component which has been hard to track down and they called back next day with one at £20... and I know the list for a new one is £400. I'll be back, as they say in the movies.

[joejag308]

Blackflash.....if im anything to go by when i decide to go it alone and source my own bits the old one suddenly starts up again like a good un.
Dont you belive it....a false sense of security these parts give unitl you aregreatly in need then they pack up altogether. carry on with the second hand sourced one anyway...I think you may still need it.....Joe

[johnweber]

i noticed the other day on ebay a company doing recon heater pumps cant remember the price though.

i also agree eurojags friendly helpful people

[blackflash]

Forgot to close this one off... David Marks fitted the unit and it took less than half an hour to do so - it's been working fine for the last few weeks.

Thanks Eric at Eurojag, and David.