harvey6480
Member Since: 30 Apr 2012
Location: Suffolk
Posts: 116
 
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Hi all, I've read and re read the manual. But can't find the fuse for the head lamps. Checked the plug and no voltage where it plugs into bulb? Can't find fuse for it? Any idea, year 2012 disco 4 with halogen lights [/code]
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 29th Jul 2014 9:29 pm |
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discoteca
Member Since: 08 Mar 2010
Location: Warwickshire
Posts: 1477
 
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Do they have fuses?
From the workshop manual:
Operation of the lamps is performed using overload proof Metal Oxide Semiconductor Field Effect Transistors (MOSFETs). The MOSFETs can detect overload, load interruption with the lamps switched on and short circuit to positive with the lamps switched off.
The MOSFETs are protected against short circuits, removing the requirement for the lamps circuits to be protected by fuses. The MOSFETs respond to heat generated by increased current flow caused by a short circuit. Normally this would cause the fuse to blow. The MOSFETs react to the heat increase and cut the supply to the affected circuit. Once the fault has been rectified or the MOSFET has cooled, the MOSFET will automatically reset and operate the circuit normally.
If an overload occurs, the current flow is dependant on the temperature of the related MOSFET and can be up to 20 times the rated current of the lamp. The MOSFET heats up and deactivates the load applied to the circuit. When the MOSFET cools the circuit is once again reactivated. This thermal cycling occurs continuously in the event of an overload occurring.
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| 30th Jul 2014 5:13 am |
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