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Mondeo Main Beam faulty

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interele | 20:16 Sat 10th May 2008 | Motoring
7 Answers
My Mondeo near side main beam ... doesn't
I've changed the bulb and the fuse, do I have to change the car next or is there something simpler I can look for :-) PS It's a 04 Ghia

Ta

M
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I believe that both main beam lights are switched via the same relay - but are separately fused (after the relay).

This would suggest that you have not changed the correct fuse, or that you have a wiring fault (did you check that the fuse you replaced is still OK - not blown again?).
Question Author
The hand book says fuse 16 and 18 - so I swapped them over. and the off side still worked and the near side didn't so I put them back and still nothing changed. Do you think one side of the relay could be faulty ?
If you have swapped the bulbs and correct fuses, with the same result (near side main beam not working), then it suggests you have a wiring fault. The most likely cause is a loose connection within the circuit. Visually inspect the wiring connections at the bulb holder, including the return/negative connection.

If you have a meter, measure the voltage with respect to the chassis at the bulb and also confirm 12V to be at the input to the fuse (can be measured by pulling the blade fuse to gain access).

If you have 12V at the fuse input and no voltage at the bulb � logically there is a break within the wiring.

I have heard of breaks in the wiring looms on Mondeo�s due to normal flexing in day to day running � but I would not expect it on a car less than 5 years old.
Modern cars make it extremely difficult to run a replacement wire within a loom.

If all else fails, you could wire the near side main beam from the battery + (with a suitable fuse) via a relay and have the relay coil switched via the off side main beam.
If you want to live dangerously, link the +12V between the near & off side main beams and up-rate the applicable fuse.
Question Author
You don't think it can be the relay ?
The handbook doesn't say where that is

M
I doubt it is a faulty relay, if it were then neither Main Beam would work.

I have a Haynes manual for the Mondeo which lists the fuses as F17 & F18 (and not as F16 & F18), it�s worth checking fuses F15 � F18 are all OK. You could pull all fuses & check that they are OK. The only down side is that you would need to re-enter the radio code once any fuse supplying 12V to the radio is pulled.

Fuses are best checked for continuity with a meter (there can be a very small break in the fuse element), but careful inspection should reveal a blown fuse.
According to my Haynes manual, dipped beam is controlled by Relay 9 & main beam by Relay 10.

The relays are located within the engine fuse box (not passenger fuse box), both colour coded white � Relay 10 is the closer of the two to the edge of the fuse box.
Question Author
FIXED !!!!

The fuse boxes are nothing like the handbook
I found the main fuse box behind the glove box
and it has about 10 times the number of fuses that the handbook says it should have

Your answer made me think ..was I actually changing the fuses I thought I was so I just took them both out and the dip beam didn't ...ooops

There are a zillion fuses in that fuse box and strangely enough there was one missing ... which
is very strange since the MOT is only about a month old - so either it wasn't in properly and it fell out or I can give you the name of a very dodgy MOT place

Anyway, many thanks - without your logical input I might have given up and had to pay a garage. So now I am happy, legal and puzzled

best wishes and thanks

M

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