headlight electrics

Right I am a bit rusty on my electrical knowledge and have a problem in the headlight circuit of my 1990 Disco 200tdi.

when the ignition is off the sidelights are working (normal) but when i switch it to dip no change No indication of dipped beam, sidelights only with the ignition on, again sidelights only. and no voltage getting to the bulb pins (on the 3 pin bulb) or the plug

With the engine started there is a dim dipped beam and a reading of 3.8 volts at the bulb so I tested it at the fuse still 3.8 went to the bulb and unplugged the bulb to make certain as soon as I unplugged the bulb on the drivers side the passengers side brightened up I checked the voltage in the plug 13.6 plugged it back in and the lights work including the mainbeam that wasnt working at all before

Turned it all off and came in for a cuppa and went out to see if it was still working (loose connection I was thinking) NOOOOOOOOOOO back to square one

Anybody come by this before I have fitted a new stalk changed the bulbs back to original 55/60w from the 100w the previous owner fitted when they are working there is no problem but it seems they need time to kick in and will work fine so long as it is not left switched off for more than 20 mins there is no relay indicated in the wiring diagrams i have no fusible links under the bonnet (they came in in 94) but from searching through reams of forums searching this forum etc I have found that the 1990 Range Rover Classic has a Dip/Mainbeam control box which as I understand it is a black box with an orange plug does anybody know if the Disco has one? because to me it points to a relay problem and there are no relays fitted

Anybody with Info that could help would be stopping a bloke from going bald through tearing his hair out my MOT is due And I cant send it in with no guarantee the lights will work HEEEEEEEEEEEEELP

Sounds like power leakage, basically something else is putting voltage to your light circuit and it's feeding the wrong way

Check lights at the back and any trailer socket for corrosion. Also look for loose wires maybe where an alarm was linked up and they wired it into the headlamps instead of indicators

It just so happens that the Alarm has been butchered out so I will check for loose wires draining the circuit as soon as the rain stops thanks for that hope it works!

Dim-dip relay for your year of disco is mounted on the steering column or in that area I believe.

Well funnily enough I've been out and attacked the relays located behind the fuses under the dash with a drift in annoyance and so far the lights work dont know how long for though