New style lights- an easy performance upgrade.
Discussion
I thought I would post this information as it may be helpful to someone…
In the original headlamp setup, dip beam goes off when main beam comes on. When retro fitting the newer style lights with separate main and dip lamps it is preferable to have the dip remain on when main beam comes on. (Some installers fix this as a matter of course, but clearly not everyone) I have seen this resolved with relays but a while ago came across a neat fix posted on here which involved a couple of diodes added to the headlamp switch box in the boot. Finally, I got around to doing this last weekend only to find that the design of circuit board was different to that in the pictures posted (no surprise there) I therefore needed to do some testing…
Well, to cut a long story short, and after stabbing myself in the thumb and blowing up the steering wheel function control box here is a simple solution to the problem…
Cut a wire!
The steering wheel control box sends 2 signals to the light control box when you hit the main beam button. The main beam signal powers a relay to turn the main beam on, whilst at the same time, the dip beam signal turns a relay off, thus powering the dip beam down. By cutting this signal wire the relay remains on, and thus the dip beam remains on.
The dip beam signal is red and blue at location B5 on the multi pin connector to the switch control box.
The plug has 2 rows of 9 connectors (A & B, but un-labelled) with 18 locations in all (but only 15 wires) Location 5 is dead centre, with 4 connectors either side. A5 is empty, so you should see a blue/red wire dead centre with no wire directly below it. Cut this wire and insulate the cut ends and that’s it! Dip will now remain on when main beam comes on.
If you have had the newer lights fitted and they are currently wired in the old format, this should improve main beam performance considerably. In my case, I could see down the road, but there was very little light in the foreground. Once the dip beam when off.
This does not resolve the fundamental problem of the voltage drop from the control box in the boot back to the bulbs, which leads to dimmer than they should be bulbs, but my next plan is to fix this with relays to bring power to the bulbs directly from the battery rather than via the boot.
Usual disclaimer… if your car blows up it’s not my fault!!
Jon H
In the original headlamp setup, dip beam goes off when main beam comes on. When retro fitting the newer style lights with separate main and dip lamps it is preferable to have the dip remain on when main beam comes on. (Some installers fix this as a matter of course, but clearly not everyone) I have seen this resolved with relays but a while ago came across a neat fix posted on here which involved a couple of diodes added to the headlamp switch box in the boot. Finally, I got around to doing this last weekend only to find that the design of circuit board was different to that in the pictures posted (no surprise there) I therefore needed to do some testing…
Well, to cut a long story short, and after stabbing myself in the thumb and blowing up the steering wheel function control box here is a simple solution to the problem…
Cut a wire!
The steering wheel control box sends 2 signals to the light control box when you hit the main beam button. The main beam signal powers a relay to turn the main beam on, whilst at the same time, the dip beam signal turns a relay off, thus powering the dip beam down. By cutting this signal wire the relay remains on, and thus the dip beam remains on.
The dip beam signal is red and blue at location B5 on the multi pin connector to the switch control box.
The plug has 2 rows of 9 connectors (A & B, but un-labelled) with 18 locations in all (but only 15 wires) Location 5 is dead centre, with 4 connectors either side. A5 is empty, so you should see a blue/red wire dead centre with no wire directly below it. Cut this wire and insulate the cut ends and that’s it! Dip will now remain on when main beam comes on.
If you have had the newer lights fitted and they are currently wired in the old format, this should improve main beam performance considerably. In my case, I could see down the road, but there was very little light in the foreground. Once the dip beam when off.
This does not resolve the fundamental problem of the voltage drop from the control box in the boot back to the bulbs, which leads to dimmer than they should be bulbs, but my next plan is to fix this with relays to bring power to the bulbs directly from the battery rather than via the boot.
Usual disclaimer… if your car blows up it’s not my fault!!
Jon H
Top man!
Don’t forget if you’re doing that you’ll need an extra earth wire as there is only one to each side & if you are running both lights at once it’ll be carrying too much load adding to the voltage drop (I think!)
When I fitted the twin lights I fitted a load of directly powered relays to try & make the lights both work together which was initially very successful, but they were overly complicated & have now developed some kind of back feed problem – I’ll use your guide to simplify things – thanks!
Don’t forget if you’re doing that you’ll need an extra earth wire as there is only one to each side & if you are running both lights at once it’ll be carrying too much load adding to the voltage drop (I think!)
When I fitted the twin lights I fitted a load of directly powered relays to try & make the lights both work together which was initially very successful, but they were overly complicated & have now developed some kind of back feed problem – I’ll use your guide to simplify things – thanks!
Luckyone said:
they were overly complicated & have now developed some kind of back feed problem
Solution to feed back would be a relay that has two outputs. One supply goes to mainbeam and the second goes to the dip relay (I fitted mine under N/S headlamp) meeting up with the dip feed from the boot which I use only to switch in a separate battery voltage feed. Alternatively the main beam could activate the dip supply relay via a rectifier,diode. There are plenty of electronic experts on PH who will know what to do. I did not follow this route myself (or fit 100W bulbs) because of fears of damage to the reflector from high Watt output. The uprated earth is something that helps anyway. Getting new reflectors really helped my light output as did xenon bulbs.Gassing Station | Cerbera | Top of Page | What's New | My Stuff