Interesting read on the car electrics. Worth a read !

[12345]

Hope you find this interesting. It is for the s40 but some of the info should be similar to the xc90

http://theeshadow.com/files/volvo/S4...Electrical.pdf

[AB-UK]

Can you give us a clue as to why you think it's worth a read?

[Clan]

It is worth a read because it gives you an understanding of how a modern cars electrics work , which is completely different to what you are probably used to . You have to know how it works before you have any chance whatsoever of fixing anything !

[12345]

It helped me understand how the Xenon angle sensor work. I know it's not the xc90 but it made me realise how bloody complicated the Volvo electrics can be.

[Clan]

Originally Posted by 12345

It helped me understand how the Xenon angle sensor work. I know it's not the xc90 but it made me realise how bloody complicated the Volvo electrics can be.

It is not just volvo , all cars and even motorbikes are like this now .. Actualy in real terms it is a lot more simple than the old non-network systems as most units basicly ( in simple terms ) just has a live feed and an earth and a single or double wire to tell it what to do and for it to communicate with any other module on the car , you dont need to know anything about the signals going back and forth , but just know if there is a signal there or not ..
For example the instrument panel , on the old 760 with the fully populated instrument panel there were about 60 wires going into it ... todays instrument panels give a hugely increased amount of information , but only have 3 wires going to it ...

[Tannaton]

Originally Posted by Clan

It is not just volvo , all cars and even motorbikes are like this now .. Actualy in real terms it is a lot more simple than the old non-network systems as most units basicly ( in simple terms ) just has a live feed and an earth and a single or double wire to tell it what to do and for it to communicate with any other module on the car , you dont need to know anything about the signals going back and forth , but just know if there is a signal there or not ..
For example the instrument panel , on the old 760 with the fully populated instrument panel there were about 60 wires going into it ... todays instrument panels give a hugely increased amount of information , but only have 3 wires going to it ...

... I would also throw my two penneth in and add that the new, digital network systems are also generally more reliable than the old, analogue systems. I can't think of any essential electronic module that is particularly hard or expensive to get second hand as they so reliable there are more second hand ones available than is demanded.

We are lucky as Volvo owners that it is so easy and cheap to get hold of the proper diagnostics.