How I fixed an electricity issue in my car
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Get the course for $99Not the usual content on this blog, bnut this is an interesting story to tell I believe. I own a 2015 Chrysler Town and Country minivan. It is a really good car and filled with electric components. The side doors, the booth, there are 2 screens a DVD player and a bunch of other stuff. Awesome when all is good, not so much when something breaks.
Last summer, one morning my battery was drained. I charged it and it got drained again next night, so I went to a car electrician, explained the issue and booked an appointment to check the issue. I tried to charge the battery again, but it wasn’t charging so I got a new one. Since it was an the older side, I assumed the complete drain two times killed it, so I replaced it and the car was fine for about a week or so and I even cancelled the appointment but then it drained the battery again. So I took the car to the shop and they told my that my radio has a parasitic draw, I need to take it to an electronics shop and get the power button replaced or get a new radio if that doesn’t fix the issue. I did this and got the radio fixed, my battery drain went away and it seemed that everything works fine.
Then one they the dual sided AC acted up and was blowing hot air on one side, even though it was set to 22 celsius. Then the radio froze a few days later. This happened once years ago, but happened maybe two times and by the time I would’ve took it to a shop, the problem disappeared on its own. This time, it actually got worse and the car displayed a “NO BUS” error on the console and the windscreen wipers started to run all the time. Then my signals stopped working and the electric windows as well. My battery also started to drain again so I had to disconnect it. I took it back to the same shop, but they said this will be an issue with the cars computer module, the electronics shop is the one that can look into that. So I went there, but this was beginning of December, they were fully booked till the new year and the owner recommended to take it to another car electrician and told me it might be a short causing this somewhere. So I took the car to the recommended shop and they supposedly checked the wiring and told me there is no short, it must be the computer module that causes it. So I went back to the electronics shop, got an appointment and parked the car for more than a month. Oddly, when I took it to the appointment, everything worked for about 10 minutes while I got to the shop. They took out the computer, tested it and told me it works fine, it must be a shorted wire and they even found some rodent shit, that was indicated that something might have chew on a wire. So I went back to the car electrician, but he told me that he already checked the wires so he can’t do more and sent me away.
I realized that maybe the official service will be able to help, so I went there, but apparently they don’t have a car electrician, so they were no help. This was the point, when I first tried to fix the car myself. I googled the issue and found some people that had the same problem and a video of a mechanic debugging such issue, where he explained how this car has a CAN BUS for communicating between the electronic modules and the computer of the car and if any modules is broken or has a short, it breaks the hole system. His recommended way of debugging it is to disconnect modules one by one, until you reach the faulty module and the error will go away and everything will start working. So I disconnected the radio, the DVD player, the two front doors, the rear screen and HVAC, the front HVAC but had no luck. I was a pretty dissapointed and was trying to find another car electrician to look into it because I assumed that someone that does this for a living should have an easier time figuring out the problem. And I found another shop. I took the car there, told them the history, told them something drains the battery and that the car computer module was tested and has no issue. They supposedly checked the car and told me that I need to replace the fuse box, which is called a TIPM(totally integrated power module) module as I learned it later. I went to the official service to order one, but they gave me a funny look and told me that this part costs a thousand euros, and they rarely replace it, if it acts up, an electronics shop can usually fix it. This was the time when I realized that this TIPM is not just a fuse box, it is also the computer of the car. I told them to hold off with ordering one and decided to give another go to fix the car myself.
I bought a multimeter and learned how to diagnose a parasitic draw. I measured a 1amps constant power draw and another roughly 1amp, that was not constant. So I started to unplug the fuses and it turned out the radio is the culprit of the parasitic draw. I disconnected it but the 1amps draw stayed even will all fuses disconnected. I unplugged the socket for the radio harness and started to check the wires for a short circuit, found one, and then found a tear on that wire. I patched it up, but it didn’t fix the CAN BUS error. In the meantime I purchased the service manual of the car to get the wiring diagrams and to have a better idea of where to look for things. And I watched and read a lot of content about diagnosing such issues. Rule number one seems to be is isolating the parasitic draw or the short. I realized that I did’t disconnect the rear camera last time, so I gave a try to that too, but didn’t help. I disconnected my tow bar’s electronic module too, but no luck. I started to suspect that it might be an actual wire leading to the radio, so I started to check the wires from the radio socket and I found one with a short. I checked the wiring diagrams and it was the wire for the CAN BUS. I went back to my laptop and checked how this CAN BUS is laid out and that’s when I noticed that there is one more module on this network that I haven’t checked: the blind spot detection system. I remembered that was actually broken when we purchased the car, but I never bothered getting it fixed. So I checked where it is located and took off the rear bumper to access it. I disconnected it and went back to my multimeter still hooked up to the radio socket. The short was gone, but I thought maybe I am just not touching the wire properly or something, but anyways let’s connect the battery and see what happens. When I did that, everything was back to normal!
I couldn’t believe it. I didn’t use this car for 4 months because of this issue, went to multiple shops to get it fixed and the problem was such a small thing and I was able to diagnose it spending less than 2 days on it with my limited knowledge about electricity.
Madness.
The positive side of the story is that I learned a few new things and it got proven again that you can do anything with curiosity and determination. The internet has pretty much all the knowledge you would need to be honest.
And yes, I tried AI to help diagnosing this, but it was useless. I learned a bunch from Youtube videos though.
