hello all, 1996 300tdi defender 90. Just failed my mot and to be honest it was a shock lol. I switch on the headlights and they both work. Put main beam on and the drivers side comes on but passenger side goes out completely? Any ideas of what to check so I can get fixed quickly. Cheers
One head light goes out when main beam is on
- Thread starter Murdo1uk
- Start date
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check earths
flat
Well-Known Member
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Looking good doesn’t necessarily mean electrically good!
neilly
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Are the earths not shared? for main lights full and dipped for each side.
If you have a meter pull the connector on the back of the headlight and start checking if you have voltage on the full beam side, if not then go back through the wiring and see if you have a dodgy connection.
Cheers
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Check the headlight connectors have not melted. Change for ceramic.
Yeah the earths are shared on each side. They come off the back of the light through a grommet and bolt to the wing next to the radiator and oil cooler at the front. Time to get the meter out and check everything today.
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Knackered bulb.
That would be my first suggestion as well. Start simple and cheap. When main beam comes on dipped beam switches off. So if the main beam filament/circuit of the bulb is damaged it will cause these symptoms.
Ok, I plugged the whole headlamp that’s not working into the good side and everything works. Main beam and dipped all good.
Made new earths up and connected to the wing, left off the headlamp and tested the 3 pin plug and have 12v on dipped then switched on main beam and nothing.
Checked fuse....all good
Ran a wire from main beam plug to the main beam switch and tested continuity and all good.
Not sure why I have continuity but no power?
Oh dear
Made new earths up and connected to the wing, left off the headlamp and tested the 3 pin plug and have 12v on dipped then switched on main beam and nothing.
Checked fuse....all good
Ran a wire from main beam plug to the main beam switch and tested continuity and all good.
Not sure why I have continuity but no power?
Oh dear
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did you actually swap headlights or only try one, as it may be due to the loading of 2 headlights on at once.
I only switched one over, I’ve taken both headlights off now and switched main beam on and only have power on one side. The other side has nothing.
Checked all fuses and they’re good
Checked continuity from the main beam switch to the plug and all good.
tottot
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Poor contact in fuse box ?
[GALLERY=][/GALLERY]
ive unscrewed the fuse box from the bulkhead, pulled the fuse out and looked to see if the connectors are through enough for the fuse to go into and they’re in the right spot
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I thought that the headlight power went to the offside headlights then piggy backed across to the nearside?
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Large Chivas Regal and repeat several times. Take the tablet in the morning.
Yes doctor
Check to see if you have power at the fuse connector, that will tell you if it is the switch side or the light side, the switch only has one output but feeds two fuses. As one side works that would indicate the switch is ok and as low beam works the earth must be ok.
