So I drive a mix of trucks. One Scania has H7’s and the other has the H4 with no drl’s. My question is on the one with the H4, when you flick to main beam, should you lose your dipped headlights?
Dipped headlights stay on when flicking to main beam on the H7 are they are a fantastic light.
THE old 1980’s DAF 2500/2800 twin headlights,like many continental cars like Merc and BMW,worked with single filament bulbs which provided dip beam on the outers and main beam on the inners.The result being dip and main beam combined when the main beams were on.
While Brit cars like Jag provided both main and dip twin filament on the outers and seperate main beams on the inners.The Jag was far superior to the dip and main set up of the BMW or DAF with the twin main beams more than compensating for the lost dip.
On that note I don’t think you can have combined dip and main on together with twin filament bulbs only one or the other.With twin filament single lights obviously being the worst of all worlds if that’s what you’re describing as you’ve only got one set of dip ‘or’ main beam lights.
H4 are twin filament bulbs, dip and main in the same bulb.
H7 are single filament, dip and main being different bulbs, so dip can and generally does stay on when main beam is used.
H4 three connection prongs, H7 two.
You will see the difference if you look through the light lens at the bulb…bulb off 
…H4’s are near enough twice the size of H7’s, worth knowing the difference so you carry both types of spare with you, assuming you are allowed to carry out such jobs.
Juddian:
H4 are twin filament bulbs, dip and main in the same bulb.
H7 are single filament, dip and main being different bulbs, so dip can and generally does stay on when main beam is used.
Congrats Juddian, you’ve just provided me with the most pointlessly interesting fact of the day 
toonsy:
Juddian:
H4 are twin filament bulbs, dip and main in the same bulb.
H7 are single filament, dip and main being different bulbs, so dip can and generally does stay on when main beam is used.Congrats Juddian, you’ve just provided me with the most pointlessly interesting fact of the day
Well funnily enough…more pointless twaddle alert…the Mrs’ car has proper factory fitted HID dipped beams, not sure what all the fuss is about them mind they are a whiter light but so bright anything outside the beam pattern might as well be a black hole, anyway the main beam are normal H7 halogens which gives a two colour pattern on the road when on main beam because those HID dipped lights stay on.
Now i’ve lost the bloody plot of what i was going to say 
Other than what i was going to say and that will maybe pop into the confused mess of what once passed for my mind in about a month 
, what i will say is if you fit H7’s yourself make sure they fit snugly and fully into the holders, which are quite fiddly, because even if they are out a fraction the beams are all over the bloody place, i’ve lost count of the number of times i’ve had to take headlights bulbs out and refit them properly on bloody wagons.
So what’s the answer?
Should the H4 dips stay on when you flick to high beam or is it normal to lose the dip?
On the H7 I don’t lose the dip when I flick to main beam.
Zane99:
So what’s the answer?Should the H4 dips stay on when you flick to high beam or is it normal to lose the dip?
On the H7 I don’t lose the dip when I flick to main beam.
The H4 uses the same bulb for dipped/high beam as like said above its double filament, the H7 cant do this so trucks with H7 headlights normally have an extra bulb for main beam (usually H1)
So yes you will lose the dipped on a H4 as both parts of the bulb wont usually light up together
chaversdad:
Zane99:
So what’s the answer?Should the H4 dips stay on when you flick to high beam or is it normal to lose the dip?
On the H7 I don’t lose the dip when I flick to main beam.
The H4 uses the same bulb for dipped/high beam as like said above its double filament, the H7 cant do this so trucks with H7 headlights normally have an extra bulb for main beam (usually H1)
So yes you will lose the dipped on a H4 as both parts of the bulb wont usually light up together
Thanks Chaversad, probably part of the reason why most Scanias come with extra spot/foglights, where you can switch the spotlights so they come on automatically with main beam.
If both filaments fired up the heat in that single light unit would be too much, about 140w, anyone remember when 100w bulbs became available for cars, put a pair in my Sierra and they promptly melted the dipswith.
chaversdad:
So yes you will lose the dipped on a H4 as both parts of the bulb wont usually light up together
^ This.
As opposed to this.That’s progress.
