H4 Headlamp wiring

[Pete 21]

Hi guys- could anyone who has changed out headlamps to H4 bulbs please advise; I'm fitting H4's to the outer head lights, hence need to install the caps with extra terminal to accommodate main and dipped connection. Do I basically just tee off the blue/white wire that currently serves the inner (main) so the outer is served by both blue/white and blue/red enabling main and dipped?
I will still be using H1s on the inner main. Both new H1s and H4s are 30% brighter bulb variants which based on same wattage I'm assuming means no other modification needed.

[sujitroy]

Sounds logical. Some will say add relays. I added LEDs and didn't bother with relays.
Sujit

[StagJonno]

Not recommended on 2 counts:
1 - You'll overload the High Beam circuit (incl Blue/ White wiring, lighting stalk contacts, main lighting switch contacts)
2 - Having both Main & Dip on at the same time in the outers will create more heat than designed for, so filaments likely to burn out quickly, plus probable heat damage to the connector and wiring inthis area.

I, like many, have put H4 in the outers in order to access to superbright bulbs, but the high beam is left unconnected.

If you really need all 4 on main beam, then you'll need to introduce relays to overcome the above issues..

[trunt]

Short answer is yes,

long answer is that it’s probably wise to put the mains at least on a relay as you are doubling the load on that wire and its switches.. Both main and dip is even better as Relays, when fed directly from the 12v power are going to assist in getting the most voltage/brightness out of your lights.. and prevent burning out the switches..

edit.. +1 on overheating the outers.. relays are the way to go!

[StagJonno]

Sounds logical. Some will say add relays. I added LEDs and didn't bother with relays.
Sujit

I suspect LED H4-types will also have overheating problems if both main and dip are on simultaneously. LED H4s I've seen have large heatsinks to shift the heat of the drivers in the (almost) sealed space behind.

[Pete 21]

Thanks very much for the advice guys. I think I’ll go ‘dip only’ on H4 outers for now and come back to it for the relays later.
Follow on question based on what StagJonno said please. I’m putting new H1s in the main inners which are also +30% bulbs. Is there an additional benefit of H4s over H1s, i.e. why go for them in the outers rather than H1s if staying essentially with same set up as original ‘all H1s’ (albeit all +30%).

[StagJonno]

For me, when I got my car, a PO had fitted Cibie (Valero) lamp units, the inners being H1, the outers P45t (I think now obsolete). Fortunately, I found P45t -> H4 adaptors, which gave me access to the superbright H4 range, which I find most satisfactory. The other good thing about my Cibies is that the H4 can be set for LHD by a fixed rotation of the bulb.

Some folk have fitted H4 lamps in all 4 locations and, using suitable relays and fusing, operate 4 x dip and 4 x main. For anyone interested, send me a PM with your email address and I'll send you a copy of my suggested wiring arrangement (adapted from one on Grampian Stag website, amended to include fusing in each lamp filament so you don't get plunged into darkness if a fuse operates ). This is too large to attach on here.

I did buy a pair of H4 LED bulbs but never got them fitted which I could be persuaded to part with - they were £100 and reckoned by a mate to be the best available, having tested several..


.

[Pete 21]

Thanks for your help on this

[Staggering About]

I have H4 bulbs in all 4 lights. This gives 4 mains and 4 dips.
The diagram is on my website http://www.grampianstags.net/Headlights.htm

[Wheelz]

I used relays to implement a 4x4 operation. One thing I didn't like is, that with all 4 on dipped, the load on the alternator when stopping caused the belt to squeal. This would soon drain the battery if doing a lot of driving in very slow/stationary traffic.

[malc4d]

Mine (LHD) has the RoW setup, H4 outer, dip/main and H1 inner, main It now runs through relays. If you have the repair manual and look at the electrical pages it will show you how they are wired..

[BRGStag]

I replaced mine about a year ago when one of the sealed beam units packed up.
I couldnt get any H1's at the time so fitted two pairs of H4's, thinking of a possible upgrade in the future as others have done. However, I found that the mounting plates have slightly different locating slots which mate with the tongues on the back of the lamp units. This is presumably to prevent fitting the wrong lamp unit!!
I had to lengthen ( Ithink from memory) the top left hand slot on the inners by about 5mm to allow a straight fit and the rim to fit.
I stuck with the original layout of outer dips and inner mains with brighter bulbs.
The worst bit was that actually the sealed beam hadnt gone, it was the wiring at the lamp connectors. Also all the wiring across the front of the car was cracked and crumblig, so I replaced it all back to two relays fitted below the bonnet stay area, with a line fuse to each lamp, and a new feed directly from the battery.
Fed the relays from the two left hand headlamp cables cut back to good about where they appear out of the inner wing so all operates as original with reduced load on the column switches.
At 40+ years old, probably a new loom would be the best way forward.