General  100hp Rear Electric window conversion

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General  100hp Rear Electric window conversion

I saw an MOT advisory recently that said "rear doors don't open". I was a bit surprised that the car passed.

It was a Fiat 500X.
Even i thought that's an MOT faliure. Should get my MOT's done there in the future :unsure:
 
Even i thought that's an MOT faliure. Should get my MOT's done there in the future :unsure:
There no requirement for the rear door to be able to opened from the inside


Driver and passenger doors must open from the outside using the relevant control.

Driver and front passenger doors must also open from the inside using the relevant control.
 
There no requirement for the rear door to be able to opened from the inside


Driver and passenger doors must open from the outside using the relevant control.

Driver and front passenger doors must also open from the inside using the relevant control.
@koalar do you have the wiring diagram for the four pin Abarth 500 series 4 switches. Ive just got a set. Its just thrown me that there are 4 pins and not 5?

Normally you have illum 12v and ground. Then a common feeding up or down!? :unsure:
 
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Panda and 500 use 4 pins

Common
Light
Up
Down

The switches don't carry any current the just tell the body computer to switch on the motor relay

No idea if they are up to being used to directly control the motor long term

Screenshot_20251127-134413.png


500 above but the panda is pretty similar
 
Panda and 500 use 4 pins

Common
Light
Up
Down

The switches don't carry any current the just tell the body computer to switch on the motor relay

No idea if they are up to being used to directly control the motor long term

View attachment 476931

500 above but the panda is pretty similar
So the fiat 500 switches use a pull down logic and a feed form ilum for lighting switch. I havent actually looked at the panda switches yet but i need 5 pins. I suppose i could get the other side of the LED for illum wire but they are very fiddle switches. I would not use these as direct drive they are certainly some sort of pulse logic. Im not going to be using the BCM off the Pandar.
 
So the fiat 500 switches use a pull down logic and a feed form ilum for lighting switch. I havent actually looked at the panda switches yet but i need 5 pins. I suppose i could get the other side of the LED for illum wire but they are very fiddle switches. I would not use these as direct drive they are certainly some sort of pulse logic. Im not going to be using the BCM off the Pandar.
If it were me I would just wire them in separately from the cars systems. Im sure this would work and be easier to do. It avoids upsetting anything else too. You could then get any window switches and pick a switch on size. I would forego the illuminated switches as in the back these are probably not worth the trouble
 
So the fiat 500 switches use a pull down logic and a feed form ilum for lighting switch. I havent actually looked at the panda switches yet but i need 5 pins. I suppose i could get the other side of the LED for illum wire but they are very fiddle switches. I would not use these as direct drive they are certainly some sort of pulse logic. Im not going to be using the BCM off the Pandar.
Yes switch is used pulled down logic to earth senses by the body computer same both panda and 500

Body computer has miniature relays built in to them to operate the motors

Assuming a standard 10K pulldown inside the body computer the switch is only handling around 0.005A

Might even be less never measured, but the handbrake switch is 3V
 
@koalar do you have knowledge of this LIN bus is standardized under ISO 17987 (Parts 1–7), with ISO 17987‑4 being the critical reference for electrical interfacing

If i use an Arduino with a Lin interface i need to know the correct codes and frames?
 
Sorry missed answering this one

Yes you can connect to the canbus using something like an Arduino

No idea if if it's full compliant

But an Arduino Nano and a MCP2515 CAN adapter works, there's no point in reinventing the wheel, the canhacker software and MCP2515 library already exists and work

It's a faff to set up, computer baud rate, can adapter baud rate, ECU baud rate, for example there's several versions of the MCP2515 with different baud rate, it your matchs the original it will just work, if it's different you have to alter the config file (forgotten what it's called) before up loading the sketch to the nano

When you get it working you end up with a list of dev id on one side and the value on the other

I can't remember what I was trying to achieve at the time, but the problem I encountered was, simple things was doable as the PIDs are standard, but if you wanted to do some that more model specific like say turn a fan on or off you don't know what the PID is

You could sit there taking wait for the fans to switch on, take a snapshot repeat until you see a pattern, this value before and this value after

I lost the will going down this route, you can do a very similar thing with the elm327

Using a elm327 terminal you can set the protocol, send a header, send data, get an answer or something like that, I couldn't find an app that would auto do some of the typing in the first steps instead of having to type them in every time, I am sure one will exist, but I lost interest after downloading a few

I don't think the ELM327 would work as a canbus wide sniffer, there is a command for monitoring all, but at around 500 kbps I doubt it can send it all back to to the computer quick enough before a buffer overrun error, could be wrong, you can limit the date used and monitor, I not tried this but it's no different to a scan tool app just with the nice graphics
 
This seems to be getting very complex for something as simple as a set of rear electric windows.

Id just use switches from an older car designed to carry the current of an electric window motor and add in a one touch relay of which there are many in older cars.

No need to involve arduinos or canbus.

I’m sure my Punto mk2b could close the windows off a long press on the remote, you may already have the signal needed to close all the windows from the remote.
 
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