I've spent the last week looking at various electrical issues relating to a newly purchase S/H Volvo S40. I am a firm believer in safety first and being a father of 3, but also a student I plummed for a cheap (perhaps TOO cheap) 1996 edition S40.

I replaced (thanks to some wiring advice on here) the electric aerial with a 3rd party unit, which works perfectly. Today I cut up and soldered a stereo harness suitable for the Sony stereo to fit the Volvo and it worked perfectly. The aerial extends when you select RADIO and comes down when you hit CD. Perfect!

However, I continued with sorting out other issues and discovered that the fuse for the cigarette lighter (position #13 on the fuse diagram) is missing a fuse.

I noticed that this position is also the data relay systems and I am wondering what the long term effect of having no fuse fitted in this position would be? What sort of data transfer are we talking about and if the previous owner failed to replace or deliberatly removed it, what does this indicate?

The dashboard constantly shows a 'Service' light (car with cross through it) and he informed me that this had happened 18mths beforehand. He owned the car for exactly 2yrs, which means that throughout the previous owners time this car wasn't really performing this 'data relay'.

Of course I'll replace the fuse tomorrow (I need the 12v output for my mobile) but any advice about the data relay would be very useful.

a shop should be able to plug in your odbII port to a computer for around 50$ ( well, here in can. its around that ) and tell you the problem..unless someone else has a better idea.

Hi, I've noticed that little port at the side of the steering column. I don't think there are actually any problems as such, I am generally interested in the fact that a fuse in position 13 is missing, which is listed in my S40 users manual as providing power for a data relay.

My question is, what data is being transfered (from what devices from which areas of the car - precisely what type of data is being transfered?).

...AND if the fuse is missing (and no relay is occuring) what data is failing to be sent, to what devices and what would be the long term effect of this?

It could simply be something stupid like the external air temperature failing to be passed onto the dashboard read out, or information for additional equipment I don't have such as the 'Winter Pack', but I am concerned that it was deliberately removed to stop the flow of important or vital data for the trip computer for instance.

Anyone got any clues what this data relay actually relays?