I'm glad that there is a discussion in this thread! So let me answer, and give my view about it.
freddofrog said:
ouch, no, CANbus is an important part of the car, the later the model of car, the more that CANbus is used by the systems to "talk" to one another. AFAIK you would find it almost impossible to transplant anything from 8th gen to 7th gen (and vice versa), and there are some small differences between 7th gen pre-facelift and 7th gen facelift.
below is a schematic of the CANbus in the 7th gen (click on picture to make it bigger)
In particular, the ECM/PCM (aka engine ECU) turns the compressor-clutch relay on and off (i.e. the engine ECU turns the A/C compressor on and off). The engine ECU gets its instructions to do this from the "gauge control module" over the F-CAN. The "gauge control module" gets the signal from the "relay control module", which is interlinked with the climate control unit.
Notice that the Navigation unit is also on the F-CAN, this gets info from the engine ECU which can be found in the menus.
You're a braver man than me, and as I say, you seem to have found a way round it, but are you sure that the A/C is working ?
Yup, you are right. I was misled by the Ga-NET protocol, which is used mostly in the multimedia devices, so if you want to hack your navigation unit, you need to sniff on the Ga-NET protocol(which is an IEBus protocol in it's nature). I think that the CAN is pretty much the same in both, pre-facelift and facelift ones. The instrument cluster
(gauge control module called in the Workshop manual) is the gateway between the car's ECU and all rest modules in the car. This is my next point for work. I will buy a facelift gauge and try to fit it in. Probably I will fail, but why not to try ? Currently my A/C is working great, with all options and auto/manual control. Everything is fine, but you are right. I had some troubles. First I'm not sure why I had the A/C module troubles, because when I bought the facelift Head unit it was from right-hand Accord, and mine is left-hand one. When I installed the unit, everything started, the A/C was working only in auto mode, the relay was switching well, I could increase/decrease the temperature. But my manual menu (when pushing the A/C button on the navi) wasn't working. Also the head unit on the top (the small segment display with the clock, above the navi screen) wasn't showing the temperature. Then I decided that this upgrade is impossible, and I only can use it partially. Then I decided that the problem is in the A/C control unit inside the Head unit. It was for right-hand car and mine was left-hand. So I took a part both head units. I put the pre-facelift A/C module in the facelift head unit. Put them together and installed them in the car - and banggg! The A/C was working on 100% functionality! Manual mode, head-up display and everything. So, what was the problem? I'm not sure, in my opinion it was the difference in the A/C modules. If it was a CAN bus problem, how the old A/C module would work with the new touchscreen and the new menu? See the pictures.
TypeR said:
Just seen this thread and have to say i'm very very impressed. This has been something that pretty much everyone has said cannot be done.
I have to say it was a risky task but it has worked for you big time.
I would only ask that maybe you do a writeup to help the other members who want to do this.
Brian they said that it was impossible to put face lift sat nav into a pre face lift but this guy has worked it out, I am a firm believer that most things with a little patience and a lot of tinkering can be done.
Once again morpheous this is by far one or the best mod I have seen on this site
Hi, and thx for the nice words!!! I started this modification with the thought, that I will fail. But I said that I should at least try it. If it fail I will resell the facelift modules and refund. Then go to the next inpossible project and so on
Why I'm not still did the writeup of this project? Because I cannot guarantee that it will work in 100% on every car! I could mislead someone to spent money for nothing, and it will be my fault! So I just share my experience and my results. I think it could work on every car, probably not from the first time, but this thing is so modular, you can take a piece from facelift car and put it in prefacelift- awesome!!! This is the first part of my bid mod project for this car, which includes - facelift gauges (probably fail here
), if the gauges mod fail, I will try to make some trip computer for this 2004 year sh*t... And the last part is to hack the Ga-NET multimedia protocol, and make a module to interface the OEM navigation screen with car PC. It's already done, not something new, but it's not opensource project, and the modules are expensive (at least expensive for me). See this thread -
http://typeaccord.co.uk/forum/topic/12486-2004-i-ctdi-owner-with-carpc/?hl=ga-net
freddofrog said:
I don't recall anyone ever saying it was impossible .....yes 8th-gen <--> 7th-gen has been said to be impossible, but not facelift into pre-facelift, just not straightforward and possible CANbus differences
However, he hasn't confirmed that his A/C is working, and if it's a diesel, I doubt if it will
note that I gave him some "likes", am I the only person round here that gives out "likes" for effort and apparent success ?
and am I the only one who got the Spanish Inquisition on details about the difficulties involved ?
The car is 2.2 i-ctdi, so it's a diesel one! I know the problems with the diesel A/C, but it's with the Chinese aftermarket units. Their target is the US market, so they don't care about diesel models
So in conclusion, I would say that if the facelift unit has problems with the A/C, you need the prefacelift module (small PCB connected to the A/C control buttons PCB).
Unfortunately I can't do this mod on another car, to double check. So if anyone wants to try, he is welcome to write to me and I will help with what I can. The success is not 100% sure, but this makes it more desirable