Problem electrics rear screen

Problem electrics rear screen

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Chamorange

Original Poster:

146 posts

174 months

Saturday 18th June 2016
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Hi,
Trying to fix a problem with my rear screen on 2003 T350.
Press the button to put it on and it blows the 10 amp fuse number 25.
It does not blow the fuse for the rear screen itself which is a 30 amp fuse number 26.
Disconnect the rear screen at the back window and still blows fuse 25
Removed the relay R03 for the rear screen and still blow fuse 25 when I press the button.
Disconnected both plugs inside the doors for the wing mirror controls and heated mirrors and again fuse 25 blows.
Therefore cables from the relay to the rear screen must be okay, which leaves the circuit from from and to fuse 25 !
Wing mirror controls all work fine, when I press the heated screen button the red light just flashes before fuse 25 blows.
Fuse 25 also controls speed sensor, mirror ECU, rear screen and dash heater blower LEDs. Everything works except for the rear screen so the problem must be between fuse 25 supplying the control voltage for the relay R03.
Just forced the relay closed and the rear screen heated up, so that does confirm that the supply to the relay, to the rear screen and the rear screen are all okay.
Does anyone have a circuit diagram for showing how it's set-up or have any ideas before I pull the fuse box apart?
Thanks

Chamorange

Original Poster:

146 posts

174 months

Sunday 19th June 2016
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Progress :-

Disconnected the mirror ECU and the fuse 25 does not blow !

Buttons light up for the wing mirror control and rear screen , so make some progress.

Ordered a second hand mirror unit and will plug that in and test it at the weekend.