S80: Electrical Fuse problem on V70 Estate 2008

[Dogcarrier]

I have been struggling with a nagging fuse problem for 6 months. The fuse that covers passenger seat, interior light and driver's door window control panel blows [when it feels like it], it seems. I have tried isolating each it component one by one. Looked for wire breaks where I can, changed interior light and control panel by swapping with a friend all to no avail.

Can anyone help????

[Boatie]

Have you checked the connections on the fuse holder itself? Might be worthwhile checking the current flow of each component as near to the fuse holder as possible using a digital meter of sufficent capacity in series.

Frank

[GrantA]

Have you checked the size of the fuse (amps)? As the circuit includes the "passenger seat" the fuse that is fitted (and you keep replacing) might be of too small a rating as the seat will draw a high current. I suggest checking the fuse rating with what it says in your manual and, if it is correct, disconnect the seat for a while and see if the fuse still keeps blowing.

As they both draw a large(ish) current, and the wiring moves during their operation, I believe it is the wiring on either the passenger's seat or the driver's door window that is damaged and is earthing somewhere.

PS. Is it fuse F17 that keeps blowing? Just checked and it should be 7.5A

[Dogcarrier]

Thanks to Boatie and GrantA for replies, I believe the problem is the seat but have disconnected it for a reasonable time to no real result . It is fuse 17, do you think it is worth using a higher rated fuse?

[GrantA]

Originally Posted by Dogcarrier

Thanks to Boatie and GrantA for replies, I believe the problem is the seat but have disconnected it for a reasonable time to no real result . It is fuse 17, do you think it is worth using a higher rated fuse?

I could go into a big long explanation about how fuse ratings are calculated but the simple answer is NO...... It is not wise to just increase the fuse rating to overcome a fault which could be an earth and could result in the wiring overheating and catching fire. (If you do decide to put in a slightly larger fuse say 10A then you must accept the consequences if your car burns out.)

Are you able to carry out the checks suggested by Frank (Boatie) as that would clearly show which circuit is being overloaded? Your problem is the fuse is blowing intermittently "[when it feels like it]" so tracing a fault will always be difficult. You said you disconnected the seat "for a reasonable time", did the fuse blow at all when the seat was disconnected? If not I would leave the seat disconnected for up to a month just to confirm it is the seat.

Sorry I can't be more helpful, chasing electric faults in cars can be a nightmare and you could end up with the insides ripped out and the passenger seat on a bench in bits, good luck.

[KBB]

Originally Posted by Boatie

Have you checked the connections on the fuse holder itself? Might be worthwhile checking the current flow of each component as near to the fuse holder as possible using a digital meter of sufficent capacity in series.

Frank

Worth noting that most DVMs when used to measure current in series only have an internal fuse rating of 10 amps, some of the more expensive ones 20 amps.

Either way if you use this method to fault detect a short to ground it will blow your meter fuse be it 10 or 20 amp.

Have a look at the below thread giving advice on how to trace and locate a short to ground.

http://www.volvoforums.org.uk/showth...50#post1814050