E85 only blows hot air on max

[diydel]

Hi All
Just joined with a 2007 2.o Se. Had it a week now and have just managed to clear the transport mode of heating system (multiple software attempts but got there in the end) however my joy was short lived as although everything appears to work, it’s not right. I only get hot air if I set it to max temp anything below that and it’s cold air(manual or auto) screen defrost blows hot air also. Anyone have an ideas ? Cabin sensor somewhere?

Thanks
Derek

 

[Z43.0Si]

Seems strange. I know if your coolant is low it can effect the heater output. Might be worth a look if you haven’t checked it recently? Just a thought....

 

[diydel]

Thanks, coolant already topped up though. Must be water in matrix to blow hot air when on maximum (or that’s how I see it)

 

[Z43.0Si]

Yes, that’s the case then.

I guess you need to get a fault reader on it to hopefully point you in the right direction. I suppose it is plausible that the temp selector is faulty? If it was working fine before the car went into transport mode though I’d suspect some other electrical gremlins

 

[Ducklakeview]

The aux water pump on the 2.0 is known to fail, and it's only purpose is to push hot water through the heater matrix..

Mike

 

[diydel]

Thanks Mike. If it didn’t get hot at all I could see it being the aux water pump, but this works on the highest heat setting and defrost so can’t see it being the pump. But thanks for your input

 

[Ducklakeview]

There is still some flow through the matrix if the pump isn't working. They added it as the 4 cyl cars weren't putting enough flow through the matrix, which was sized for the 6 cyl cars. Check the hoses at the bulkhead both feel hot, if one is a fair bit cooler, then there is either air in the matrix, or the pump has failed. I've diagnosed and replaced about half a dozen cars with this, and a used (£25) pump has cured every one.


Mike

 

[diydel]

Thanks Mike. I’ll check later. Seeing the pumps so cheap and a potential problem I might replace it anyway. Where do you normally get the pumps from?

 

[Mike6]

Had these exact symptoms on my daughter in laws Ford Focus and it was the thermal fuse near the heater motor. Ford wanted silly money for the unit (you guessed it fuse not sold separately) so went to Maplins and paid about 20p for a correct rated fuse, soldered it in and been working fine since. Reason thermal fuse went was a clogged cabin filter. Could be a similar set up on the Zed

 

[derin100]

I've just taken my 3.0Si out of a few weeks storage and have this exact same problem i.e only get heat when the temperature dial is turned up to max (which is then far too hot!); if I turn it down even one click below max = no heat at all!

Is it likely to be the same problem?
Thanks

 

[Anonymous]

I had the same problem on an old merc. Heater Matrix was buggered

 

[derin100]

Just put a new battery in...as the old one had irretrievably died...and problem solved! Heater and control thereof working fine now.

If it had gone into the infamous 'Transport Mode' it seems to have righted itself without me even needing to get it re-coded. Weird.