EVIC dont show ambient temperature, only dashes "_ _"

[Chungungo]

Hello Guys
I have seen many threads about this topic but still cannot find a complete answer.
My Jeep Liberty 2004, 4x4 diesel manual transmission it was for Europe, and somehow Jeep did not install some things on it, like EVIC, Cruise Control, steering wheel radio controls, etc.. But it hass all the connections installed, like the light bar harness and fuses.
I have been installing all these things by myself since I figured out that the Jeep was built for all of this, they just did not put it on it.

The thing is that I followed this thread Installing an OTIS which is very very good but I still cannot make work the Ambient temperature in my EVIC, I already have a 2002 OTIS and a 2002 EVIC, part number 56042756AG , both of them show dashes "_ _" for the temperature.
I have checked wiring continuity and temperature sensor ohms as well, everything its fine, but I am still having a hard time to make it work.

This YouTube post it’s interesting but I have not gotten any answer yet to my questions.
https://www.youtube.com/watch?v=ezgUHSKo4JM&t=191s

In some other post I have read that the year of the EVIC has to be the same than the year of the Jeep, is it this the only problem? It is really the year of the EVIC what makes the difference?, or it could be something else....

Please help.

 

[Chungungo]

I created this post to concentrate all what I can collect about the EVIC showing dashes “_ _ “ in the Overhead Temperature but in only few pages and no other topics, please don’t hate me but I did it to reduce the pages and maybe to get a different answer. Please let’s keep it this way.

I have done several researches and this is what I have collected from other threads in this forum and others and some videos as well.

- Installing an OTIS says that any EVIC/OTIS should work.
Main link = Jeep Grand Cherokee WJ - Overhead console and EVIC
Direct link = Installing an OTIS
…and the troubleshooting says :

If you see the compass display, but there are only dashes "---" where the temperature should be, you have one of two problems:
1- You did not install the Ambient Temperature Sensor, or you didn't install in the plug all the way. Check your connection of the sensor.
2- You have a short somewhere in the PCI Bus connection (the violet/yellow) wire. Check your connection.



- A quick summary of the 41 pages thread HOW TO: Install an EVIC or OTIS (overhead computer) is like this:

a- The only reason that Grand Cherokee EVICs don't show the temperature is because 04+ are CANBUS based, like the DCx LX platform. Prior to that they were compatible with the Liberty, which still runs PCI.

b- Where people have had issues, is in 2004+ I think the BCM was changed, so everything except the temp works.

c- Technically, you don't need an 04 Liberty EVIC for an 04. Any model that works on the others also works fine on the 04's. You will not get the "ambient air temp." readout unless you use the 04 EVIC on the 04 Liberty.

d- To have a working ambient temp indication, stick to your model year.
2002-2003= Evic '99-'03
2004-2007= Evic '04-'06(07?) but NOT from a Grand Cherokee...


- A YouTube post showing that may be something with the HVAC control unit to the CTM control to the Overhead console.
https://www.youtube.com/watch?v=ezgUHSKo4JM&t=193s
I made a question but I don’t think I will get any answer, the post is very old.



So, having collected all the above info I come up with these thoughts and crazy ideas that might help to solve this issue, and maybe if we get lucky it would be nice to have that EVIC from 2002 (part number 56042756AG) with Instant MPG and showing the temperature in a 2004 Liberty (and maybe others) as well.

If the way that EVIC communicates with the rest of the components depending on the year is like this:
To the BCM (Body Control Module in the interior below the driver dashboard, left hand) = 02, 03 Liberty, which read the temperature from the sensor in the front grille.
To the PCM (Powertrain Control Module in engine compartment) = 04+ Liberty, get the temperature information from here.


I tested continuity in my connections and the Blue/Yellow wire from the Temp sensor goes to the PCM pin number 4 (I did not see any numbers but counted from top to bottom), and the Purple/Green wire goes to the pin number 8.
SEE PIC




Another thing is that I found out that the Temp sensor wires have somehow a connection to the engine fuse box at fuse #5 which is the EATX (Electronic Automatic Trans Axle,… I believe), but in my Jeep this connection is missing, it only has one tab (pin), the other one was not placed by the factory, and of course there is no fuse because it would not make sense. ….I wonder why they just did not install both tabs (pins), only one does not make sense.
The thing is that there is continuity with both Temp sensor wires to the same electric tab, ignition off and battery connected, but if I disconnect the battery then there is no continuity. It would be interesting to know what would be this.
SEE PIC



I am not a mechanic, neither have any electronic knowledge, but In summary, and thinking that is not possible to flash the BCM and/or EVIC to update the software, I have two crazy ideas that may not be good at all, but if someone who knows better about electronics can help it would be great,…. and please stop me if I am wrong so no one gets confused:



1- I wonder if there Is any way to connect (splice) the temperature sensor wires from the PCM to the BCM, so the BCM can send the correct signal to the 2002 EVIC??, can someone tell??, if this is a good idea, where should I connect the BCM??, I don’t want to take everything apart to do continuity testing before knowing better if it is a good idea or not.

2- And even crazier, would it make any sense to disassemble the Fuse box to see if there is connections behind for the EATX and adapt it or install a tab (pin) in order to place the missing fuse, with this the circuit would be closed and maybe complete what is needed for the EVIC to read thru the BCM??, My Jeep has Manual transmission, and I guess this is why they didn’t bother with this EATX connection, …..but maybe affects how the 2002 EVIC reads the Temp sensor output??

 

[Chungungo]

Hello, can someone help.
Thank you!!