hid upgrade on discovery 1 results........

No longer have them fitted, have gone over to normal bulbs operated with relays powered from the aux battery

Pretty sure there was a wiring diagram on here on how to do that, used about 4 relays IIRC.

there is - in the CFAQ section.

Yer found it
http://www.landyzone.co.uk/lz/f38/headlight-wiring-upgrade-72348.html

Can anyone explain in dumb arse terms the reason for fitting this? Can I run my new +120 bulbs with OE wiring?

Your bulbs are just standard H4 bulbs so yes, although now filled with Xenon gas giving an increased light output of up to 120%, so yes.

As an electrical engineer I can only think the designer had an old American vehicle with negative switched lighting therefore using relays to change polarity something we did 35+ years ago.

gR@HaM said:

Can anyone explain in dumb arse terms the reason for fitting this?

Click to expand...

The wiring mod?

The lights should be brighter using a direct battery feed

gR@HaM said:

Can anyone explain in dumb arse terms the reason for fitting this? Can I run my new +120 bulbs with OE wiring?

Click to expand...

the disco headlight stalk is a known weak spot and is prone to burning out. Putting higher current bulbs threw it is asking for trouble. By only using the stalk,to switch the relay(s), you reduce the load on the stalk, but still get bright(er) lights.

Ah, so if I fit these bulbs there's a chance the electrics on my steering column could burn out leaving me stuck on the road with no lights!!
wish I new that before ordering them

+120's are still 55W - they are not 120Watt, so no more so than a standard 55Watt bulb.

I see thought they were 120w :5bblush5:
Going back a few years (probably 12!) I remember fitting some Xenon gas halogens to my Ford escort and being pretty disappointed, think they were marketed as 'ice white'. Anyway shall see what these 120s are like, 120% improved visibility is a pretty bold claim!

gR@HaM said:

I see thought they were 120w :5bblush5:
Going back a few years (probably 12!) I remember fitting some Xenon gas halogens to my Ford escort and being pretty disappointed, think they were marketed as 'ice white'. Anyway shall see what these 120s are like, 120% improved visibility is a pretty bold claim!

Click to expand...

Im pretty sure its 120% light output rather than 120% vision, and if I was being pedantic then surely its simply +20% rather than +120%

DiscoPol said:

Im pretty sure its 120% light output rather than 120% vision, and if I was being pedantic then surely its simply +20% rather than +120%

Click to expand...

no
its +120% - coz yu can also get +90% as well.

I wouldn't worry about the light output to much it's how long they last, I understand that is an issue with some bulbs.

I still run on 50% bulbs that were purchased from Halfords around 8 years a go, most of the roads I drive now in my part of the world are illuminated now anyway so not a problem.

I bet this percentage claimed is based on the basic halogen bulbs that were around in the 70s which were dim but still better than what was around before that

The Mad Hat Man said:

no
its +120% - coz yu can also get +90% as well.

Click to expand...

I stand corrected

DiscoPol said:

I stand corrected

Click to expand...

Said the man in the orthopaedic shoes..

gR@HaM said:

Said the man in the orthopaedic shoes..

Click to expand...

Gah you beat me to it!!!