Fuse 3 blows instantly - Page 4

HarryM1BYT · 29th December 2013, 15:05

Quote:

Originally Posted by Bolin

I have had a re-occurance of Fuse 3 blowing.

A mystery.

I rather thought it might. Replace it with a 12v lamp and start waggling wires about. There should be no need to disconnect the battery, to change a fuse unless something is intermittently breaking down.

Bolin · 29th December 2013, 15:12

Thanks Harry, but I have waggled all the wires as they normlly would be in use (more so actually) by moving the seat through all positions - any wiring moving due to bumps etc would surely have been evident in the last two years, I have been down some very bumpy roads!

On that basis, I cannot believe that pulling up the carpet and pulling apart the dash will actually produce any meaningful result. Also, the work the garage carried out should not have involved going anywhere near any of the wires mentioned - so it could have been a genuine co-incidence.

The only thing that would have been drawing power when I was attempting to change the fuse back in 2011 would have been the clock I believe - but it has been fine for over 2 and a half years.

Erm....

HarryM1BYT · 29th December 2013, 15:19

Quote:

Originally Posted by Bolin

Thanks Harry, but I have waggled all the wires as they normlly would be in use (more so actually) by moving the seat through all positions - any wiring moving due to bumps etc would surely have been evident in the last two years, I have been down some very bumpy roads!

Faults causing fuses to blow, can be both in the wiring and in the items being supplied. If you are sure its not in the wiring, maybe fit local fuses close to each item on the circuit to try to localise it?

Has someone maybe added some extras to the circuit?

SD1too · 29th December 2013, 15:24

Colin, what value is your fuse 3?

Simon

Bolin · 29th December 2013, 15:48

Quote:

Originally Posted by HarryM1BYT

Faults causing fuses to blow, can be both in the wiring and in the items being supplied. If you are sure its not in the wiring, maybe fit local fuses close to each item on the circuit to try to localise it?

Has someone maybe added some extras to the circuit?

I could try that, thanks for the suggestion, but as it's been 2 and a half years since the original problem I could be in for a very very long wait to find out what is causing it.

Presumably either the seat or clock, as the trader I bought the car from said they moved the seats lots and it stopped working, but they had also looked at the clock hence me finding a packet of uses behind it, in the dash, and also the garage could have moved the seat when moving the car or have adjusted the clock to correct the time (I think previously they had used a memory saver, not sure on this occasion).

There doesn't appear to be anything added - the car did have a bluetooth phone kit when I bought it, but that was wired into the audio loom and is long gone, and nothing to do with fuse 3 as far as I can see.

Quote:

Originally Posted by SD1too

Colin, what value is your fuse 3?

Simon

5 amps, as per the label under the closure panel and the handbook.

HarryM1BYT · 29th December 2013, 16:19

Quote:

Originally Posted by Bolin

5 amps, as per the label under the closure panel and the handbook.

I don't think 5amp will be nearly enough for seat motors, maybe it only feeds to seat control /seat memory circuits?

Thought so....
This is relevant - 'check f3 fuse and fuse f19 and fuse f21 ,if your car is up to 2003 and fuses f9,f51 and f53 on 2004 onwards ...

So then - either your seat memory, the clock, or the diagnostic circuits have an intermittent fault. Your choices are to fit individual 2.5amp fuses on each circuit until the fault blows one circuit, or to try to provoke the fault into showing up, or examining the circuits very carefully.

As already said replacing just F3 with a 21w lamp, would cause the lamp to light up, the instant the fault occurs - as an easy option.

Bolin · 29th December 2013, 20:26

Thnaks Harry - I have just re-read the thread and from my OP I see that when I tried inserting the fuse with the seat connector and clock disconnected, the fuse blew upon insertion, so presumably the problem is in the wiring or diagnostic socket.

I didn't try inserting the fuse with the battery connected this time - I wanted to avoid the 'flash' and wasting a fuse, so not sure it this would still happen.

Still don't understand why the fuse would have blown upon insertion but just disconnecting h battery made everything normal.

I'm not too worried about this problem, just curious really.

HarryM1BYT · 29th December 2013, 21:46

Quote:

Originally Posted by Bolin

Thnaks Harry - I have just re-read the thread and from my OP I see that when I tried inserting the fuse with the seat connector and clock disconnected, the fuse blew upon insertion, so presumably the problem is in the wiring or diagnostic socket.

I didn't try inserting the fuse with the battery connected this time - I wanted to avoid the 'flash' and wasting a fuse, so not sure it this would still happen.

Still don't understand why the fuse would have blown upon insertion but just disconnecting h battery made everything normal.

I'm not too worried about this problem, just curious really.

Only a sudden surge on powering up, would cause the fuse to blow, yet perhaps not blow with the battery disconnected. There is nothing which could cause the sudden surge on the circuit, so it must have been entirely coincidental that it didn't blow - basically the fault was not there. Diagnostic sockets are sometimes abused, sometimes in resstting the service interval - take a good look at it, I'll bet there is a whisker of bare wire around the back of it, causing a short. .

Bolin · 1st January 2014, 17:29

I think in that case I should try removing and refitting the fuse now whilst the circuit is OK to prove that it is an intermittant problem and just co-incidental with when I tried installing with the battery disconnected.

I'll try to have a look behind the socket, needs a bit of dismantling. Can't remember how much, shouldn't be too hard.

HarryM1BYT · 1st January 2014, 19:51

Quote:

Originally Posted by Bolin

I think in that case I should try removing and refitting the fuse now whilst the circuit is OK to prove that it is an intermittant problem and just co-incidental with when I tried installing with the battery disconnected.

I'll try to have a look behind the socket, needs a bit of dismantling. Can't remember how much, shouldn't be too hard.

My OBD socket was loose, it just clips into place. Its easy to get at.

29th December 2013, 15:12	#32
Bolin This is my second home Rover 75 2.5 V6 Connoisseur SE 4dr manual Wedgewood Blue 2 04-05/06/2001 Join Date: Nov 2006 Location: N.E. Hampshire Posts: 4,623 Thanks: 289 Thanked 308 Times in 243 Posts	Thanks Harry, but I have waggled all the wires as they normlly would be in use (more so actually) by moving the seat through all positions - any wiring moving due to bumps etc would surely have been evident in the last two years, I have been down some very bumpy roads! On that basis, I cannot believe that pulling up the carpet and pulling apart the dash will actually produce any meaningful result. Also, the work the garage carried out should not have involved going anywhere near any of the wires mentioned - so it could have been a genuine co-incidence. The only thing that would have been drawing power when I was attempting to change the fuse back in 2011 would have been the clock I believe - but it has been fine for over 2 and a half years. Erm.... __________________ "...the new Rover 75, which is a fabulous car......I think it looks fabulous....It's like sitting in a Rolls Royce......For me, this is the star of the show.....it looks so good" - J. Clarkson, motoring journalist on the launch of the Rover 75 in 1998.

29th December 2013, 15:24	#34
SD1too Doesn't do things by halves Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007 Location: Former Middlesex Posts: 20,511 Thanks: 1,587 Thanked 3,749 Times in 3,181 Posts	Colin, what value is your fuse 3? Simon __________________ "Whatever is rightly done, however humble, is noble." Sir Henry Royce.

29th December 2013, 20:26	#37
Bolin This is my second home Rover 75 2.5 V6 Connoisseur SE 4dr manual Wedgewood Blue 2 04-05/06/2001 Join Date: Nov 2006 Location: N.E. Hampshire Posts: 4,623 Thanks: 289 Thanked 308 Times in 243 Posts	Thnaks Harry - I have just re-read the thread and from my OP I see that when I tried inserting the fuse with the seat connector and clock disconnected, the fuse blew upon insertion, so presumably the problem is in the wiring or diagnostic socket. I didn't try inserting the fuse with the battery connected this time - I wanted to avoid the 'flash' and wasting a fuse, so not sure it this would still happen. Still don't understand why the fuse would have blown upon insertion but just disconnecting h battery made everything normal. I'm not too worried about this problem, just curious really. __________________ "...the new Rover 75, which is a fabulous car......I think it looks fabulous....It's like sitting in a Rolls Royce......For me, this is the star of the show.....it looks so good" - J. Clarkson, motoring journalist on the launch of the Rover 75 in 1998.

1st January 2014, 17:29	#39
Bolin This is my second home Rover 75 2.5 V6 Connoisseur SE 4dr manual Wedgewood Blue 2 04-05/06/2001 Join Date: Nov 2006 Location: N.E. Hampshire Posts: 4,623 Thanks: 289 Thanked 308 Times in 243 Posts	I think in that case I should try removing and refitting the fuse now whilst the circuit is OK to prove that it is an intermittant problem and just co-incidental with when I tried installing with the battery disconnected. I'll try to have a look behind the socket, needs a bit of dismantling. Can't remember how much, shouldn't be too hard. __________________ "...the new Rover 75, which is a fabulous car......I think it looks fabulous....It's like sitting in a Rolls Royce......For me, this is the star of the show.....it looks so good" - J. Clarkson, motoring journalist on the launch of the Rover 75 in 1998.