2 replies to this topic

[np90]

evening all, had a bit of a weird one with my mini, had an mot today, previous owner has fitted electric windows, and at the station it shorted/ blew a fuse,

 

the 35amp one in the four fuse box one at the top, and it also unknown to me took out the indicators and brake lights,

 

after a bit of fault finding and i did look at all fuses initially they all seemed fine tested them after and found it had blown, so yeah changed this fuse and the electric windows fired up again,

 

however the brake lights/ indicators were still out, however hazards were still working?... checked all earths, and probed different connections, anyway eventually the brake lights started working then after a bit more faffing about, i switched the hazards on then switched the indicator on with the hazards, switched the hazard switch off then the indicators were randomly working,

 

indicators and brake lights are now working, im a bit confused however how the windows blew the 35 amp original fuse, the windows do have their own circuit with a fuse in the glovebox though, so i would have thought it should have blown this first?

 

but yeah i have no idea what happened and how i got the lights working, however ideally want to sort out any faults now and avoid them in future, if anyone has had this similar problem,

 

thanks

[phillrulz]

What rating is the fuse in the glove box, plus think how the 35A fuse has all othse other circuits already loading the fuse. The initial start up of any motor is extremely high current as a motor is a deadd short till the magnetic field is built up. 

 

Also it has been said before, Glass fuses as like in the engine bay box are rated at their blow current. Plastic blade fuses i assume in the glove box, are rated in continuous current. AKA a 20A blade fuse will take 20A, 21A will blow it slowly. Where as a 20A glass fuse will blow at 20A. 

[andyapanel]

Is it possible the window motor is drawing so much current that there is not enough in the battery for the other circuits that are demanding it too?
I would check the voltage with/without the window motor and then do the same with the engine running and the Alternator making a contribution.

Electrical problems can take time to isolate; good luck.