Electrical problems Ford Mondeo 2009 MA TDCI Diesel Auto

[Christon]

I've posted about this a few times now, however after seeing yet another person about it during a routine service, I have some more information.

So basically around 6 months ago now I bought a 2nd hand Ford Mondeo 2009 privately for $5000. It was an ex Uber, the only thing wrong with it was the cruise control didn't work.

The first thing I did was take it to service the airbags as I found it was part of the airbag recall, after doing this, the cruise control was working flawlessly.

I then decided I wanted a aftermarket radio in it so I bought a cheap one from eBay that fitted the Mondeo nicely and had it installed by a nearby Car Audio place for $170ish. Very similar to this one: https://www.ebay.com.au/itm/7-Car-CD...frcectupt=true. The car audio guy warned me that these "chinese brands" occasionally don't supply the right harnesses but they will try anyway.

Lets just say the place seemed apprehensive to install it, but I assumed it was because they wished I bought one of their $1000 head units instead of my own, they certainly didn't give any further information beyond the harness thing.

Anyway as the job was nearing completion, the place rang up and advised if I knew the engine malfunction light was on. I was 80% sure it wasn't on before I took it there, but I figured maybe I'd not noticed or maybe it was coincidental. Nonetheless I figured it was probably something minor and proceeded back to the place to the car up.

After picking up the car I was very happy with the radio, it fitted nicely and seemed to work great. The check engine light was definitely on, and I proceeded to notice a bunch of other electrical's were no longer working, most notably the cruise control, but also the heated seats and also the air conditioner.

I took it to AutoBahn nearby my place who told me the following two fault codes:

P003A17 - Turbo / Supercharger boost control
P212100 - Throttle pedal position switch circuit range error

They mentioned there were other fault codes, but for now, these were the main ones.

They told me the Intercooler hose was soft and leaking and was the first thing that needed fixing and would cost $650.

I decided to save up and drive the car as is and get a second opinion when it's due for it's next service. Which I very recently did.

I should note that during this time the car ran fine outside of the issues already mentioned, and still is running fine, however the second mechanic gave me alot more information than the first did.

He said the intercooler hose was fine. He noted the throttle pedal position error, also the radiator fan was not spinning the entire time he performed the service (I've monitored the temperature since however and it doesn't go above halfway). He proceeded to read out to me maybe about 10 - 15 fault codes and mentioned a bunch he cleared off.

He had a look at the air conditioner and said there's a full tank of gas but it's not communicating with the control unit.

At this point I was confident potentially all my issues were electrical and all started when I had the radio replaced or at least most did. Well the engine malfunction warning didn't start until the radio replacement, and it's still on now.

Well, I changed the radio back to the stock radio and plan to not use the cheap one from eBay again, I may sell it probably. This didn't fix any issues, which I've assumed is because the damage was already done. So I proceeded to check all relevant fuses, under the bonnet, centre, and rear of the car, the ones I checked seemed fine. Beyond these things I can only assume it's some blown fuse or wire or something somewhere caused by the radio. I'm not an electrician, but based off what I can assume maybe the cheap aftermarket radio caused a short circuit, or was draining too much power, causing electricial problems elsewhere. The only other alternative is the people who installed it cut a bunch of wires for fun... but I'm no expert, and I had a good look behind the head unit when I replaced it.. it all seemed fine to me.. but what do I know I guess.

I mean, it sounds like mechanically the car is fine, certainly the last mechanic I saw seemed to think this, and even said it was a good car, other than the long string of electrical problems that seemed to all start when I had some car audio company put an aftermarket eBay radio in my car. Like at this stage, I'm pretty used to not having cruise control or air conditioning, which are the main things I kinda wish I had at this point. I'm just so darn curious as to what is causing all of these problems, because I seriously don't think it's a bunch of little issues strewn throughout the car, I think it's some centralized problem happening somewhere causing a bunch of little issues.. once again I could be completely wrong, but I can't afford to get all these little issues looked at.

I can only hope someone in these forums might know where I can start, what may be causing the problem, what I could do to fix it. I'm not afraid to try things myself, nor am I afraid to take it somewhere and pay provided I know it will fix the problem/s and not just be another investigation.

Any help would be greatly appreciated!