A while ago whilst driving had smoke come from ashtray/fuses stopped quickly to find a fuse burnt out - removed it.. -it was the daytime lights - drove it for about year without these lights as they are not a UK MOT test requirement. Recently I got round to soldering in a new fuse holder (on flying leads as the original holder was beyond repair and i didn't want to replace an entire fusebox) On trying the lights i now have, as well as the correct daytime lights, front and rear and the instrument lights, the headlights are glowing dimly. The headlights work fine when switched on, but i dont think they are supposed to glow when the daytime lights are working???

after a short 3 mile run to the local supermarket i found the new fuse holder was quite hot, so my assumption is that the headlamp glowing issue began before the fuse burnout (and probably caused it)
Any ideas where to go / what to check to fix this headlights glowing when daytime lights are on?

 

has the wiring been mucked about with?

often when one light comes on dimly when you turn something else on, there's a bad ground between them.

 

I thought of an earthing problem, but don't think its so... the headlights work OK full brightness dipped and main beam... and the daytime running lamps seem to glow full brightness too... I've had the car 8 years (best £50 bargain ever!) and this is the first electrical issue i have had in that time apart from seeming to blow a few more bulbs than other cars over the years.. replaced the rear clusters as they were cracked and generally poor condition.. and the front corner clusters as each got broken by other people hitting me in car parks

I shall tomorrow connect an ammeter at the fuse and see what current is being drawn there.. can anyone else with healthy daytime lamps measure the current at the fuse .. pretty please with cherries on top

Wiring not been mucked about with to my knowledge!

 

with the engine running, and a system voltage of about 13.8V, a 55 watt lamp (typical dip beam) would draw 55/13.8 == 4 amps. a smaller bulb, less, a higher wattage bulb, more.

 

Well i found my Ammeter wont read that high ( max 2 amps) and should be around 5 amps plus..

I successfully tried upgrading the replacement fuse-holder, ( it was just too lightweight for the job) and am pleased to say now its working OK

as for the glowing headlamps.. they seem to be intermittent, but are totally independent of the Daytime Running Lamps.. if i turn the light switch on the dash slowly., the daytime lights extinguish before the less bright parking lamps come on and as i turn further they temporarily go off before coming on with the headlamps... however the "low glow" of the headlamps is there whilst i turn from Daytime Running Lamps through the off and the parking light coming on and of the headlamps glow at a constant low level

I have spotted a few other 740s exhibiting this, however if i remove the DRL fuse (23) the headlamps stop all this glowing, but work normally.

 

We don't have DRL's on 740/940 here in the USA so I dunno how they are supposed to work. The one car I had with them, a 1996 Volvo 850 Turbo, there was a screw slot in the corner of the headlight switch, turn it 90 degrees and it disabled the DRLs, yay, done.