The MGF Register Forums

Hi guys spent all of Easter doing a list of jobs on George .
Rub down clear rust and respray black surround round front windscreen . Done
Take out old walnut dash stuff put new in . Done
Clean and reproof soft top .done
Put stereo in as previous owner took his after market one out .
Got original mg radio/cd player should be an easy job ? Not so .
When I went to have a look at the wires in space where stereo sits found above loose blue wire no idea what or where it comes from ?
Any of you guys have any idea please .

I bet that is a trigger wire for a sub.

I agree, blue wire is often a trigger for something else that need to be switched on when the head unit is powered up.

Sounds like bomb defusing eh!
Depending on what you've got and the stereo unit concerned, one colour blue can be to sub activation, but also another for a powered aerial. This goes from low volts when unit it off to high volts, as a trigger to the device, but NOT a power feed, I was sorting my Uncle's MG C and an innocent miswire of the control box for the powered aerial (yurgh!) led to that trigger wire being overloaded so it won't deliver a strong enough trigger anymore and is fairly directly off an embedded chip of the unit.
On a standard aerial you shouldn't need to do anything, just keep it insulated. The aerial plug, and typically the two odd-shaped ISO (?) plugs - one for power and the other for speaker connections.