Help with halogens please

[GrahamFountain]

I haven't used 4 pin relays, so I've never seen that issue - the 3-pin ones I've used work whichever end of the electromagnet is north.
I hadn't seen the explicit note about pin 30 connected to ignition fed side of the fuse, but inferred it had to be that way from the fault description.

Like Jeroen I was concerned about feeding the lights through the ignition switch. But I can see that feeding the lighting switches, and so the relay pin 86 (or 85), off the ignition switch might have some advantage - you can't leave the lights on and walk away. But it may need another relay for the sidelights as well.

Graham

[MIG Wielder]

To be fair, the heading for that diagram does state the design is based on a specific Halfords relay, a HEF 555 which has a spec; on their web-site. No diodes; no extra contacts; so if you use any other component you have to ensure it at least meets the basic requirements before using it.
Tony.

[Carledo]

I have wired the relays in as per Jeroen’s suggestion.

87 pin - headlights side.
86 pin - column side.
85 pin - earth.
30 - power from ignition side of fuse box.

I have the 30 on the brown side directly put on the take off on the battery cable but battery will be fine also. 30 on the switched side isn't advised as all the light feeds go through the ignition switch and a few extra meters cable.

The drawing does work that way but currently a lot of universal 4 and 5 pin relays have a diode fitted over the coil. These cannot be fitted as in the drawing and create immediately a short to ground when switched on. That's why it's the best to use 85 as ground and 86 as pos feed so nothing can happen during installation or replacement.

Jeroen

Forgive my ignorance, why are they now complicating life by putting diodes in relays when they never used to? i've been using 85 as switching feed and 86 as earth since I first started fitting relays more years ago than I care to remember. All the relays on the Dolomega (13 of them now) are wired this way round including some that were Vauxhall specific. But everything works!

Steve

[GrahamFountain]

I'm still trying to think of a situation where I want to have the headlights on with the keys out. But I'm not succeeding.

Nearest I can get is setting up when camping with the missus. But I think that's just getting two in tents.

Graham

[tinweevil]

Forgive my ignorance, why are they now complicating life by putting diodes in relays when they never used to? i've been using 85 as switching feed and 86 as earth since I first started fitting relays more years ago than I care to remember. All the relays on the Dolomega (13 of them now) are wired this way round including some that were Vauxhall specific. But everything works!

Steve

Short version: Ringing. (no, not cut & shut ringing nor similar)
Slightly longer version: Inertia. A coil has electrical inertia. When the current flowing through a coil is asked to stop it gets a bit annoyed. It is flowing in a most excellent way and wants to continue doing so. It will leap gaps and thus it will burn the contacts at each side of the gap. This is why points burn out. Diodes give the current inertia an alternative path to flow through. Eventually, with a path through which to spin it's wheels, the current realises it has no energy source so like a milk float up Porlock Hill it dies a sad, diminishing death.
The full version requires a brain that hasn't seen quite so much alcohol under the bridge since university. Sorry. Gurgle flyback diode.

[Carledo]

I'm still trying to think of a situation where I want to have the headlights on with the keys out. But I'm not succeeding.

Nearest I can get is setting up when camping with the missus. But I think that's just getting two in tents.

Graham

I agree that ignition switched headlights is a much better idea, can save you a flat battery.

The problem as I see it, is that the ignition live lead (the main one that goes to the fusebox) isn't all that big! And you'd then, even if unfused side is used, be running the full whack of main beam headlights off it besides all the other functions. On a rainy night, with wipers, heater fan and HRW on as well, it sounds like a recipe for smoke escape to me!

You'd really need a 3rd big relay to boost the ignition power to the headlight relays. I've done something similar on the Dolomega which has a collection of ignition lives that Triumph never heard of, so I fitted an ignition switched relay to power them all via a busbar. And will be carrying a spare in the glovebox, cos if this relay fails, so will the engine and transmission!

Steve

[GrahamFountain]

Forgive my ignorance, why are they now complicating life by putting diodes in relays when they never used to? i've been using 85 as switching feed and 86 as earth since I first started fitting relays more years ago than I care to remember. All the relays on the Dolomega (13 of them now) are wired this way round including some that were Vauxhall specific. But everything works!

Steve

Short version: Ringing. (no, not cut & shut ringing nor similar)
Slightly longer version: Inertia. A coil has electrical inertia. When the current flowing through a coil is asked to stop it gets a bit annoyed. It is flowing in a most excellent way and wants to continue doing so. It will leap gaps and thus it will burn the contacts at each side of the gap. This is why points burn out. Diodes give the current inertia an alternative path to flow through. Eventually, with a path through which to spin it's wheels, the current realises it has no energy source so like a milk float up Porlock Hill it dies a sad, diminishing death.
The full version requires a brain that hasn't seen quite so much alcohol under the bridge since university. Sorry. Gurgle flyback diode.

If we're betting on an explanation I'll back EMF - L.di/dt. And since the slope of the current (di/dt) is negative when the switch opens and the current reluctantly dies, the induced voltage (EMF) is negative and can be dumped through a diode that don't shunt the coil in normal operation, but limits the back EMF to, typically 600 to 700 mV for a silicon diode (it goes up by 18 mV per for every doubling of current, or about 60 mV per decade).

But the real differential is that the diode lets modern car makers use switches that have tin foil as electrical contacts and use less shielding on databus cables, like twisted pair not cat 5 - which is threeapenceafoot cheaper. As the switches on the Doly have a reasonable amount of metal and we don't need no stinking databuses, such diodes are redundant in this context.

Graham

[soe8m]

And to protect the ecu's switching relais on and off. A lot of cars in the 90s and '00s had the diodes to protect inside the harness outside the relays but working the same with the same reason. As it's cheaper to put these diodes inside the relays directly that's how the modern cars have.

The std has always been 85 ground and 86 pos feed, these diode relays have this also. These diode relays will fit in any oe electrical system and sockets. The pinout is std 4 or 5. When a home made system one uses the 85 as feed and 86 as ground, not the std, a diode relay will short directly to ground and can cause wiring damage. When 85 is used as ground you can use whatever relay you want without creating shortcuts. As relays with diodes are becoming more common and look exactly the same the best is not to mix up 85 and 86. It does not matter then what relay (accidentally) is used.

Jeroen

[GrahamFountain]

I'm still trying to think of a situation where I want to have the headlights on with the keys out. But I'm not succeeding.

Nearest I can get is setting up when camping with the missus. But I think that's just getting two in tents.

Graham

I agree that ignition switched headlights is a much better idea, can save you a flat battery.

The problem as I see it, is that the ignition live lead (the main one that goes to the fusebox) isn't all that big! And you'd then, even if unfused side is used, be running the full whack of main beam headlights off it besides all the other functions. On a rainy night, with wipers, heater fan and HRW on as well, it sounds like a recipe for smoke escape to me!

You'd really need a 3rd big relay to boost the ignition power to the headlight relays. I've done something similar on the Dolomega which has a collection of ignition lives that Triumph never heard of, so I fitted an ignition switched relay to power them all via a busbar. And will be carrying a spare in the glovebox, cos if this relay fails, so will the engine and transmission!

Steve

But yes but no but... the current through the ignition switch would only be driving the relay coils as the appropriate light switches are turned on. The feeds to the #30 pins should, as Jeroen points out correctly, be off one of the brown leads straight off the battery (through their own fuses). The problems are in rewiring the feed to the light switch from the fused output from the ignition switch (I think the radio take-off would be right) and fitting a similar relay to control power to the sidelights. I know they only take 60 W or so, mebs 90 with a trailer, but for doing the job right an' all that.

Graham

[Bish]

To be fair, the heading for that diagram does state the design is based on a specific Halfords relay, a HEF 555 which has a spec; on their web-site. No diodes; no extra contacts; so if you use any other component you have to ensure it at least meets the basic requirements before using it.
Tony.

Not knocking you Tony. I appreciate the fact that you put the diagram here for novices like me to follow.
My fault for not buying the correct relays, end of. You live and learn.
Don’t know what the other guys are talking about, it’s all a foreign language to me!
I’m just happy to have working headlights, and with the little bit I’ve learned I can wire a relay in for the horn.

[Carledo]

To be fair, the heading for that diagram does state the design is based on a specific Halfords relay, a HEF 555 which has a spec; on their web-site. No diodes; no extra contacts; so if you use any other component you have to ensure it at least meets the basic requirements before using it.
Tony.

Not knocking you Tony. I appreciate the fact that you put the diagram here for novices like me to follow.
My fault for not buying the correct relays, end of. You live and learn.
Don’t know what the other guys are talking about, it’s all a foreign language to me!
I’m just happy to have working headlights, and with the little bit I’ve learned I can wire a relay in for the horn.

The horn REALLY doesn't need a relay, the load isn't that much anyway and it's such a fleeting thing, typically half a second at a time, that it's no problem.

However, for the reason I mentioned above (wire size of the ignition feed plus load on the ignition switch) i'd move your 30 feeds onto the permanent live (brown wire) pole on the fusebox, rather than the already heavily loaded (white wire) ignition feed.

If you have another relay floating about that you intended to apply to the horn, use it on the starter instead, it's an often longer and always heavier load than the horn and it may save your ignition switch.

To Graham, again, even I haven't bothered with a relay for sidelights, (though I have fused them) even WITH a trailer it's only 30w (4x5w on the car + 2x5w trailer) the system can cope. And I still think that, rather than rewire the whole column area, a nice juicy 3rd relay of around 40 amps is a more elegant solution if you want ignition controlled headlights, in fact, I might even DO it on the Dolomega if I can find space for another relay in my board.

Currently, my award for the most understressed relay goes to the White Spint auto I'm doing with one hand atm, it has headlamp washers fitted (useless bling but more trouble than it's worth to delete) A relay is needed to confine their use to when dip healights are on, but was a 40 amp relay REALLY necessary?

Steve

[GrahamFountain]

I put a relay on the washer pump motor because the switch is the worst, and made it very unreliable. So, the horn switch being similar, if it's started to go high resistance, adding a relay may be easier and cheaper than replacing the switch unit. Well, that was my reasoning with the washer switch anyway.

I thought the rear bulbs I just did were 21/15 W not 21/5 W. Should'av gone to specsavers!

As to putting a relay in the supplies from the ignition switch, I'm not sure what your suggestion is Steve. I can see how a relay to power the master light switch can be controlled from the ignition switch. But I want the lights to go on and off with the radio and the heater fan, not the actual ignition. So the ignition and the existing fused stuff (which I'm not bothered about) would need yet another relay separate from that for the lights. Also, an ignition switched relay for the lights can't replace the ones I have for the main and dip lights in taking the load off the stalk switch. So it's in series with them. And if it fails, all the lights stop working together.

So, with most of the load already taken off the master light switch (13) by the main and dip relays, I can turn the lights off with the ignition switch (5) in the way I want, just by rerouteing the supply to the master light switch from the white/pink wire radio feed (6), instead of through the brown wire from the battery connector (11). I can access that brown wire at the connector block (12) and the new feed at the back of the radio - or the fan switch. Actually, I think I can access it at the same connector (12), but I need to go lie upside down in the foot well to see.

If I want a new relay for the side and dash lights, that goes into the red wires from the master light switch - again, I can catch them at the connector (12). The red wire/wires from the master light switch goes to pin 86 (or 85) on this new side light relay, the other relay coil pin to earth. The red wires to the lights go to pin 87. Pin 30 on the new relay then gets powered, though an inline fuse, by the brown wire that used to go to the master switch from the battery connector. Or I might add another power feed, like those I fed to the main and dip relays from the unfused side of the fuse box (25). That means the new fuse for the side lights is located with those for the main and dips near the old fuse box. If I was doing it properly, I'd add a new 3 or 4 fuse box under the dash or in the glovebox, supplied by the brown wire freed up from powering the master light switch, and feeding pin 30 on each relay separately.

The numbers in brackets are from the wiring diagram for RHD to commissioning number 15000.

But I still have the worry I'm missing some reason BL didn't put the feed for the lights through the ignition switch, other than they didn't want to have such a high current contact in it.

Graham

[Richard the old one]

Being an old boy I can remember when it was expected for you to leave the side lights on when you parked the car at night, if the lights were feed via the ignition switch you could not do this.

[GrahamFountain]

Being an old boy I can remember when it was expected for you to leave the side lights on when you parked the car at night, if the lights were feed via the ignition switch you could not do this.

Legally, you still are:
Highway code rule 249
"All vehicles MUST display parking lights when parked on a road or a lay-by on a road with a speed limit greater than 30 mph (48 km/h).
Law RVLR reg 24"

The RAC implies you need them, even on a road with a "speed limit of 30mph or less", if facing the wrong way. But the highway code says in rule 248
"You MUST NOT park on a road at night facing against the direction of the traffic flow unless in a recognised parking space. Laws CUR reg 101 & RVLR reg 24"

But does anyone bother on side streets in residential areas? The wife parks facing whichever way she was going when she stopped, and has never been called on it.

Graham

[Carledo]

Being an old boy I can remember when it was expected for you to leave the side lights on when you parked the car at night, if the lights were feed via the ignition switch you could not do this.

Legally, you still are:
Highway code rule 249
"All vehicles MUST display parking lights when parked on a road or a lay-by on a road with a speed limit greater than 30 mph (48 km/h).
Law RVLR reg 24"

The RAC implies you need them, even on a road with a "speed limit of 30mph or less", if facing the wrong way. But the highway code says in rule 248
"You MUST NOT park on a road at night facing against the direction of the traffic flow unless in a recognised parking space. Laws CUR reg 101 & RVLR reg 24"

But does anyone bother on side streets in residential areas? The wife parks facing whichever way she was going when she stopped, and has never been called on it.

Graham

A year or two ago a couple of cops went round our village (in DAYLIGHT) and ticketed ALL the cars that were parked facing the traffic flow (and quite a few that were parked with 2 wheels on the pavement) as was their right! They must have ticketed more than 100 cars in 1 day! The indignation this stirred up was enormous, but the effect it had on parking behaviour was even more stark. 2 years later, it's still rare to see a car parked incorrectly round here.

I admit it's not common, most police actually DO have something better to do (the only REAL basis for the indignation) but the law is still the law, it's just not that well enforced these days!

On WHY BL didn't put the headlights on an ignition live, the answer is simple, in those days nobody did! The first cars I came across so fitted were VW and Fiat and that would have been early 80s.

My mum had a MkII Cavalier, built around 87, that had a rotary master light switch quite close to the ignition and she would frequently knock the lights on whilst switching the engine off to get out. The result is obvious! Even SWMBOS 56 plate Picasso doesn't have the lights wired through the ignition. That's the newest car i've got.

Steve