Miscellaneous information

Here I will occasionally add some information which someday someone might find useful.

Trailer lighting connection - pinout

This information concerns the conenction socket often found at the rear of cars to connect to the lighting system of a trailer. The socket is not totally standardised, but I can say that most I have seen are as described here. It is likely that the colours of the wires may some times be different, but I would expect the function to be always the same.

The picture on the left shows the pins of the socket fitted to the car, as seen when looking from behind the car, the function of each pin described in the table below.
Pin Wire Colour Function
A Yellow Left direction indicator
B Blue Unknown use
C White Ground (Earth or Negative)
D Green Right direction indicator
E Brown Right tail lamp
F Red Brake lights
G Black Left tail lamp

For some reason unknown to me, the left and right tail lamps are fed by separate wires. It could have something to do with having separate fuses for the left and right, so a blown fuse does not result in having no lights at all.

I don't know what the blue wire (B) is for. I had expected it either to be the reverse light or a 12V supply for auxiliary equipment on the trailer. I have not come across a trailer that uses this wire and on my Land Rover Discovery I never find any voltage on it.

Note that the letters I assigned are not a standard notation, but just to provide a link between the picture and the table.

Problem with ASUS motherboard

I bought a brand new ASUS P4S8X-X motherboard and a P4 2.66. After installing it and connecting up everything I switched it on but it would not boot. Before the Windows loading screen appeared, there was an error message "Cannot write to ESCD", and it would not continue to boot. It would not work even in safe mode. I managed to boot it with an old Windows 98 hard disk, but even then only in safe mode.

It turns out that all that is needed is to flash the BIOS with a later version and then reset the CMOS. I had 1002 in mine and I replaced it with 1004, which I downloaded from the ASUS website. Flashing the BIOS is very easy, as there is support for it directly from the BIOS itself.

For some reason, I still could not get it to work, but I now suspect that it was simply because it was 2:30am. I emailed ASUS the next morning and got a reply same day. They suggeted that I flash the BIOS, something which I had already tried without results. However this time it worked just fine.

Unfortunately I still had to reisntall WIndows, as it was crashing during boot with a 'stop error' blue screen of death. I guess it is just due to Windows getting a shock seeing everything so different from the last time it had booted. Anyhow, after resintalling Windows everything works just fine.

(ESCD is an area of the CMOS ram where Windows keeps information about Plug & Play devices that were installed. This saves time when booting up, because Windows only needs to scan for any changes from what it expects rather than getting information about all the connected devices.)

Page last updated on 14th December 2003

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