W124 Headlamp Voltage

[Number_Cruncher]

I'm beginning to look at a problem with the headlamps on my 1995 E300D. They are a bit like me - too dim to be of real use!

Anyway, I think that I need to take off the headlamps and give everything a good clean - that's fairly simple, and I don't have a problem there.

However, before I began, I took a couple of readings with my multimeter.

Disconnecting absolutely nothing, and with the ignition on, and the headlamps on;

with the +ve lead of the multimeter on the +ve terminal of the battery, and the -ve lead on the back of the live terminal on the bulbs, I get 0.75volts drop.

with the +ve lead of the multimeter on the earth connection of the bulb, and the -ve lead of the multimeter on the -ve terminal of the battery, I get 0.25 volts drop.

So, in operation, the bulbs are running at battery voltage - 1, so, they probably aren't glowing as brightly as they ought to.

I'll find the earth point, and clean that up, but I'm not expecting a huge improvement. My main question is, on W124s, is 0.75v dropped on the positive side normal, or is it excessive? I know there's a big and expensive looking lighting relay behind the fuse box - surely that should ensure there's only a small voltage drop?

Has anyone any experience of this sort of problem with a W124?

Cheers