Yes. The pipe with the valve inline is hot, and the other is less hot, but I took that as normal. I’m going to put a hose to the matrix and check for flow.
I got another suggestion about mixing flap. I have no idea where to find that so hopefully a flush will fix it. It’s torture in the cold frosty weather.


Update.
Removed hose from heater matrix and blew into it. I got a lovely flow. I discovered in the footwell quite a few moving parts when the temperature is adjusted and all looks well. A local dealer has suggested water pump .Despair here.
just to remind it’s a RHD 2007 Accord CDTi with factory satnav.

 

The air-mixing door is somewhere under the dashboard, in the air ductwork around the heater core. The parts drawings for the USA car don't really show the blend door, but looks like it's all integrated in the central HVAC stack at the very forwards end of the center console alongside your feet.

Probably some trim panels to remove, then you probably can look for a motor that operates 2 things. It operates the cable that goes to the engine compartments to the valve on the water hose. It also operates a door that sends air into the heater matrix. Maybe you can see a broken or disconnected lever down there somewhere.

Ours is on the left side of that stack, but I don't know whether they reverse the whole set of parts for the right-hand-drive cars.

 

I have a problem with cold air only too, but I dont think its the motor. When I adjust the temperature control the valve in the waterpipe to the matrix operates perfectly. Also, in the footwell I can see all the cables and arms operating as expected. other checks I performed are: plenty of coolant, renewed thermostat, romoved a waterpipe from the heater matrix and blew into it and watched a lovely flow of water. when up at temp the water pipes for the matrix are reasonably hot though one less hot. My local Honda dealer can only suggest a poor water pump. I should add when the engine is up to temp, the lower radiator hose remains cold. Im in Ireland so thats not a big surprise as its quite cold now. Anybody help? Oh its a RHD 2007 Accord Diesel. with factory sat nav. Thanks guys,

 

Sorry Jim, I didn’t notice you had responded. I added an update to my message.
But I found all those parts in the drivers footwell. It all looks like it’s moving beautifully, but you’re suggesting remove a panel to observe a door moving? What’s your thoughts on the water pump as culprit?.

 

I couldn't remember whether the motor & levers were covered up by a smooth trim panel.

I never owned the proper year Accord to know what you have to do in order to see the air ducts and check whether the flap is moving correctly. Its good that you didn't see any broken levers, but that doesn't solve the problem.

As it gets colder and colder, the thermostat sends less & less water to the radiator, even though the water pump still circulates full-flow through the engine. So the hot water goes to the radiator slowly and has plenty of time to cool down before it comes out the other end of the radiator. I guess what I'm saying is when it's cold, it's normal for the lower radiator hose to be cool. It's kind of opposite what you'd expect, but the flow of cold water is so small that it doesn't over-cool the engine.

You put a new T-stat in, but otherwise I might suggest the T-stat doesn't quite close completely.

We don't get the diesel in USA, so I don't know if the cooling system is the same as the petrol engine. In older Hondas, the cooling system really didn't like to have air bubbles trapped. Not any more starting with 2003, because air collects at the radiator cap & moves out of the system. Don't know if there's a high spot somewhere in the diesel system where air can hang out??

 

Em, at the risk of sounding ignorant, what is an HVAC test, how may i perform one on my RHD 2007 Accord CDTi with factory satnav.

Ive checked fluids, changed the thermostat, no blockage in the matrix, valve in the enginee bay at the firewall operated by temperature selection is fine, all the controls in the footwell look perfect, cables and levers unhindered, but NO HEAT! even my local dealer wont help without a full and expensive diagnostic. I got a suggestion from one chap the water pump may not be pumpimg. But I dont suffer overheating or fluid loss or white smoke

The two pipes into the heater matrix are hot, not very hot. but I have no trace of hot air not warm, only cold

Im baffled!

 

The heating ventilation air conditioning (HVAC) has a control unit (computer) that can give you diagnostic codes. Here is a procedure for the 03-07 accords to get error codes for the HVAC.

https://www.hondaaccordforum.com/for...94/#post370304

 

Wow. I had no idea about the diagnostic stuff. I can’t wait to give that a go. It’s 2:30am here, so I will wait lol. Thanks guys.

 

Hi shipo. Update. Im having trouble with the cabin heating in my accord LHD CDTi 2007my.
Only cold air blows. So starting simple, coolant level is good, valve on the hose into the matrix functions perfectly. both hoses into the matrix feel hot, Water flows through the matrix beautifully, I fitted a new thermostat, all the valves and gizmos in the footwell appear to be functioning.. So I did the diagnostic by pressing the two buttons auto+off
I got the display 88 88
Please...whats going on.
Thanks for any help.

 

Does it flash 88 on both, then flash only some of the segments?