[alecmartin19]

i'm having a problem with my headlights.

sometimes, when i have got the headlights on, and i put the brake on, the headlights go off. it only happens on dipped beam and not on main beam. the rear lights all still work as they should and so do the sidelights.

all of the bulbs are working as they should.

has anyone got any ideas as to what this could be?

also has anyone got an r33 wiring diagram for the headlights that they could email me?

cheers people! i don't want to have to take it to a garage if i can help it! however without the wiring diagrams it will take me a while i think!

 

[Mike_B]

My first thought was earthing on the rear light's, had this on an old Fiat, brake and indicate and ALL lights would flash.

You still might had a problem with the earth wires.

Best check between the chassis and the earthing on the light cluster, should be less than 2 ohms, ideally.

 

[M1 Gts]

i agree with Mike B my first thought was the earthing. easy to check with a multi meter

 

[alecmartin19]

ok! i think i may have found the problem!

under the bonnet on each side of the car just behind the headlights there is a grey plug with 3 wires going into it and 3 coming out of the other side!

on the right hand side, the middle wire is black with no trace colour, this seems to be the earth and has no resistance between it and a known good earth point. the second wire in this plug is orange with no trace colour, i have figured out that this one is a +12V supply from the switch on the stalk to control the R/H dip beam. the last wire is red with a green trace colour. i figured out that this is a +12V supply from the switch that controls the main beam!

with the lights off, i shouldn't get a voltage at any of these wires. i don't until i put the brake on. when the brake goes on, i'm getting a tiny movement in the needle, indicating less than 0.1V at the red/green wire.

with the lights on, as i expected, i get 12V at the orange wire which is the supply from the switch to the relay for dip beam and as expected i don't get anything on the red/green wire until i put the brake on!

this time, with the lights on and the brake on, i'm getting 0.2 volts at the red and green wire. with this small voltage, the lights will still work but i think when i'm driving, this voltage is becoming greater and its tripping the lights off!

does this sound like it could be the problem? i'm sure 0.2 volts is not right. could i check this wire for resistance between it and the +ve supply for the brake lights and see if there is a short there?

any help would be appreciated as its scary at night when you see a junction appearing rapidly and then as you brake it disappears!

cheers!