Blown Fuse

slipkid · Aug 14th, 2011, 12:18

Hi
My 440 94 B18u 1.8i on the Motorway decided it wanted to indicate one of my doors was open. Pulled over ( In a service station) and checked the front doors and boot and all were closed properly. On getting in the car that evening the internal lights were not working and the door open light was still on. This morning i checked the fuse No22 and it was blown so i changed it. Bingo the interior lights were working and the door open indication worked when i closed the driver door. WHEN i turned the ignition to the 2 position the door open light had come back on. the fuse had blown again. This has happened to 3 (15amp) fuses. Any advice would be great as i know sod all about car electrics
Thanks for taking the time to read this

andy100 · Aug 17th, 2011, 11:23

I know its not 100% advisable to try a higher rated fuse but I did recently when my elec ariel kept blowing its 10a, I have put a 20a in there and everything has been fine for months.

Alan C30 · Aug 17th, 2011, 19:07

You might need to watch this as the interior lights are 'normally' (on UK cars) fed on an 'earth return' loop so watch in case you have a short on the supply side to the lights? not sure what VOLVO do / did.

earth return is where the live supply goes to the bulb then to the switch so a dicky connector might short and pop the fuses, the interior light should only pull a few amps (<5)

slipkid · Aug 17th, 2011, 19:47

Thanks for the replies Gents. Fuse 22 seems to control interior lights, cigar lighter, electric aerial and door opening warning. Ive done continuity tests on all lights, cigar lighter and front door switches. All seem to be OK. When i change the fuse (it has a 15amp fuse when Haynes say it should be 7.5?) all the lights work the door switch works and the aerial goes up and down when the radio is turned of and on etc but when i turn the key to position 2 and close the door the fuse blows again. I'm stumped, does anyone have any further ideas as I'm determined to sort this out as i really miss the radio and i like everything to run perfectly.
Thanks for reading all this

andy100 · Aug 18th, 2011, 12:16

If its blowing when you shut the door then I'd be thinking it has to be a fault with the door switch. You could take it out and swap it for one of the other 3 and see if it still happens.

IanGEC · Aug 18th, 2011, 12:41

Either the door switch is playing up (as andy100 says) or maybe a cable is touching something as it flexes when you close the door ....

slipkid · Aug 18th, 2011, 17:35

Cheers gents tried your ideas and still no joy. I took the switch of the door and used it inside the car with the ignition on 2 pressed it in and out and everything was working OK i also gave the cables a good wiggle and tug and slammed the door a few times and was still working. I turned on the ignition and POP the fuse went again. So i thought i will try a 25amp fuse and that blew. So the fault must be the engine side of the fuse box. Anyone know how i can test it? Could it be worth having a look at the fuse box itself? Sorry so many questions but i,m really stuck grrr.

Leeds Lad · Aug 18th, 2011, 17:51

Cigar lighter is your main culprit, the cigar lighter is a resistive short, this is why it gets hot, however these when faulty can pull over 30 amps! Get to the wiring at the rear of the cigar lighter (there may be more than one) and disconnect them. A trick is to put a bulb across the fuse terminals, when the short (problem) is on the bilb will light up, when you disconnect the problem the bulb will go out, this serves as an indication and money on fuses.
Go to a good car spares shop and ask for a test light, this is basically a bulb with a probe on one end and a wire with a croc clip on the other end. This you will use again and agian so it is not money wasted. Good luck.

slipkid · Aug 18th, 2011, 18:18

Hi leeds lad
Ive got a multi meter is there a way i can use that??

Leeds Lad · Aug 18th, 2011, 21:28

Yes and no, the meter needs to be put into series in the circuit, which means you need the meter to be set to amps, most meters only go upto 10 amps, so as soon as the short comes on your meter is now dead!! Safer to get a test light (fiver?) and put that into the circuit and will save your meter.

Aug 14th, 2011, 12:18	#1
slipkid T5 GRRRR Last Online: Aug 14th, 2019 07:57 Join Date: May 2010 Location: Canterbury	Blown Fuse Hi My 440 94 B18u 1.8i on the Motorway decided it wanted to indicate one of my doors was open. Pulled over ( In a service station) and checked the front doors and boot and all were closed properly. On getting in the car that evening the internal lights were not working and the door open light was still on. This morning i checked the fuse No22 and it was blown so i changed it. Bingo the interior lights were working and the door open indication worked when i closed the driver door. WHEN i turned the ignition to the 2 position the door open light had come back on. the fuse had blown again. This has happened to 3 (15amp) fuses. Any advice would be great as i know sod all about car electrics Thanks for taking the time to read this

Aug 17th, 2011, 19:07	#3
Alan C30 Member Last Online: Dec 12th, 2020 20:03 Join Date: Sep 2008 Location: Aberdeen	fuses popping You might need to watch this as the interior lights are 'normally' (on UK cars) fed on an 'earth return' loop so watch in case you have a short on the supply side to the lights? not sure what VOLVO do / did. earth return is where the live supply goes to the bulb then to the switch so a dicky connector might short and pop the fuses, the interior light should only pull a few amps (<5)

Aug 18th, 2011, 12:41	#6
IanGEC VOC Member Last Online: Jul 4th, 2022 12:03 Join Date: Dec 2002 Location: Whitecross	Either the door switch is playing up (as andy100 says) or maybe a cable is touching something as it flexes when you close the door .... __________________ Currently Owned: 1999 Volvo v70 XC - Manual - Silver - V Reg Previously owned: 1993 Volvo 945 2.0 Highlander - Manual - Red - K984 UCC 1989 Volvo 745 2.0 GL - Manual - Silver - F662 NSR

Aug 17th, 2011, 11:23	#2
andy100 Member Last Online: Nov 17th, 2012 13:41 Join Date: Jul 2007 Location: Chippenham, Wiltshire	I know its not 100% advisable to try a higher rated fuse but I did recently when my elec ariel kept blowing its 10a, I have put a 20a in there and everything has been fine for months.

Aug 17th, 2011, 19:47	#4
slipkid T5 GRRRR Last Online: Aug 14th, 2019 07:57 Join Date: May 2010 Location: Canterbury	Thanks for the replies Gents. Fuse 22 seems to control interior lights, cigar lighter, electric aerial and door opening warning. Ive done continuity tests on all lights, cigar lighter and front door switches. All seem to be OK. When i change the fuse (it has a 15amp fuse when Haynes say it should be 7.5?) all the lights work the door switch works and the aerial goes up and down when the radio is turned of and on etc but when i turn the key to position 2 and close the door the fuse blows again. I'm stumped, does anyone have any further ideas as I'm determined to sort this out as i really miss the radio and i like everything to run perfectly. Thanks for reading all this

Aug 18th, 2011, 12:16	#5
andy100 Member Last Online: Nov 17th, 2012 13:41 Join Date: Jul 2007 Location: Chippenham, Wiltshire	If its blowing when you shut the door then I'd be thinking it has to be a fault with the door switch. You could take it out and swap it for one of the other 3 and see if it still happens.

Aug 18th, 2011, 17:35	#7
slipkid T5 GRRRR Last Online: Aug 14th, 2019 07:57 Join Date: May 2010 Location: Canterbury	Cheers gents tried your ideas and still no joy. I took the switch of the door and used it inside the car with the ignition on 2 pressed it in and out and everything was working OK i also gave the cables a good wiggle and tug and slammed the door a few times and was still working. I turned on the ignition and POP the fuse went again. So i thought i will try a 25amp fuse and that blew. So the fault must be the engine side of the fuse box. Anyone know how i can test it? Could it be worth having a look at the fuse box itself? Sorry so many questions but i,m really stuck grrr.

Aug 18th, 2011, 17:51	#8
Leeds Lad Leeds Lad Last Online: Nov 15th, 2023 19:57 Join Date: Nov 2008 Location: Leeds	Cigar lighter is your main culprit, the cigar lighter is a resistive short, this is why it gets hot, however these when faulty can pull over 30 amps! Get to the wiring at the rear of the cigar lighter (there may be more than one) and disconnect them. A trick is to put a bulb across the fuse terminals, when the short (problem) is on the bilb will light up, when you disconnect the problem the bulb will go out, this serves as an indication and money on fuses. Go to a good car spares shop and ask for a test light, this is basically a bulb with a probe on one end and a wire with a croc clip on the other end. This you will use again and agian so it is not money wasted. Good luck.

Aug 18th, 2011, 18:18	#9
slipkid T5 GRRRR Last Online: Aug 14th, 2019 07:57 Join Date: May 2010 Location: Canterbury	Hi leeds lad Ive got a multi meter is there a way i can use that??

Aug 18th, 2011, 21:28	#10
Leeds Lad Leeds Lad Last Online: Nov 15th, 2023 19:57 Join Date: Nov 2008 Location: Leeds	Yes and no, the meter needs to be put into series in the circuit, which means you need the meter to be set to amps, most meters only go upto 10 amps, so as soon as the short comes on your meter is now dead!! Safer to get a test light (fiver?) and put that into the circuit and will save your meter.

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