400SE Dim/Dip beam

[mad1800ti]

I have no full beam when you push the stalk away from you and the blue light on the dash does not light up, Pull it and the lights flash and the blue light on the dash does work....

The 2 diodes in the fuse board can someone tell me wot there for??

Iv now test the stalk switch/relays and fuses

[Mr Tank]

Hi

Diodes in the relay board are what help control the flash. Replace them, they are very cheap!

Andy

[mad1800ti]

I Removed the diodes one at a time from the fuse board and it made no difference at all!! Strange!!!Even with them both out
Iv tested them both 1 seems OK the other not sure it gives the same reading both ways.

[jmorgan]

Pesky earth playing up? Time for the multimeter and much gnashing off teeth.

[Wedg1e]

mad1800ti said:

I Removed the diodes one at a time from the fuse board and it made no difference at all!! Strange!!!Even with them both out
Iv tested them both 1 seems OK the other not sure it gives the same reading both ways.

A diode that reads the same both ways is generally either open-circuit or short-circuit... assuming you're testing them with meter on a diode test range and not straightforward resistance?
The diodes do form part of the headlamp control circuitry, but there were a few different configurations over the years due to different combinations of lights and changes to Construction & Use regulations that required 'dim-dip', ie the dipped beams had to be dimly lit as well as the sidelights... to do this on a Wedge meant the pods had to pop up with sidelights on. Luckily they dropped that piece of stupidity and it's feasible that your car had the facility deactivated, which may be playing havoc with the normal operation. Or the dim-dip module could be kaput, which could also cause problems. Not sure whether, strictly speaking, if dim-dip was orignal fitment it is still required to work, but you'd need a particularly nitpicky MOT man to spot it.