Halogen upgrade, relay help required

[Allan NZ P5b]

My plans are to wire the relays in to the existing circuit near headlamps or close to i.e. front guard or Front of engine compartment.
So Relays will be controlled by old circuits instead of lamps
Where do you suggest I take the positive feed from for the lights themselves?
Can I feed from no 1 fuse?
And how would you fuse these circuits.
How many circuits 1 for each side (both dip and main feed)
Or 2 each side?
Are your connections shown on your fuse box picture John Weymouth?

Attending to lots of minor wiring issues at present as my panel beater painter while very good on painting didn’t put the wiring back to my standard. It all works but I am not happy and feel it will cause me issues in the future. So am checking most of the areas where he worked. Have found some wires cut and resoldered and taped and I will run new uncut lengths or use crimp & solder jointers with heat seal covering and then recover in heat shrink. Bit paranoid on wire covering continuity as have seen corrosion wick up inside on marine installations even with tinned wire. And one of these joints may even be the source of my mysterious grounding as didn’t have this issue prior to accident and repaint

Regards

[Phil Nottingham]

Its a very good idea to protect the console light switch with a relay but the easiest option and you only need one - is to mount a compact heavy duty single pole relay behind the console just fed from the existing lighting wiring which is more than adequate for Halogen lighting. I have done this on all my P5's since I had a very near fire behind the console caused by a overheating switch which I ignored too long and which finally failed in pitch darkness one night in the Welsh mountains

If you feel you need to minimise volt drop by reducing the wiring length and protecting the dip switch as well, two relays can be mounted under the parcel shelf.


In this case its best to take a live feed from under the main battery feed terminal block behing the dash near the top as here you can pick up an Ammeter fed circuit. Another opition is a feed directly from the starter motor solenoid but this will bypass the Ammeter as the horns do. Suitably fuse this new live feed with a mini circuit breaker preferably - dependent on the Wattage of your new lights. Your mod would mean replacing the loom back to the fuse box unless you want a relay for each filament ie 4 in all.

You are correct to be concerned about corrosion the Lucas bullet type are really prone to this and its often not apparent. Some connectors are very well hidden away and some owners are not even aware they are there,

These are major mods to wiring and unless you really know about auto electrics I can only advise to consult an expert locally.

In any event a close scrutiny of the wiring diagram is required to identify the correct pick up points - choose the wrong ones or make poor connection may cause failure of the alternator or fire.

Many relays even give a schematic diagram on their casings of the wiring

[Allan NZ P5b]

Thanks Phil will digest what you have said with car and wiring diagram at hand. Sounds like option 1 is a go.
My original plan followed this logic.
I was concerned about the feed wires capacities so was planing 2 use 4 relays as they are very cheep and seemed to also allow me an opportunity to tidy up connectors by using the mounting blocks with minimal rewiring only requiring new feeds for lights and protecting everything (both switches and wiring its self) New Heavy duty feeds would give max power to bulbs. Is this sound logic?
But as always simple is best.
Have done a lot of 12 volt wiring on boats. Bit different as fibreglass hulls don't conduct so need negative circuits to everything as well so most car stuff is easier only 1 line.
I can read diagrams and usually redraw the section I am working on to make it easier to follow with out accessories of no interest to me at that time.

[Phil Nottingham]

:)Your logic is not correct for heavier wiring if the existing wiring/terminals/switches are faulty.

The wiring cores/insulation do degrade but this is usually obvious and the bullet connectors/Lucars definitely increase circuit resistance if allowed to oxidise. Dealing with these will restore the full 12v (actuallly alternator voltage of approx 14.5v) again but cannot improve it.

Its the console switch thats the weak link and if it gets even slightly warm after a few minutes of being on then its time for replacement or better still use the relay.

Heavier wiring is bulky and the terminals can be just as troublesome if not more so

[dorsetflyer]

Alan, yes the wiring to the fuses is as per the photo.
If you have your wiring diagram to hand you can see which is which by working from the top down.
No.1, 3, 5, 7, etc are on the left and are the main feeds. No.2, 4, 6, 8 etc are on the right, and are the wires to the accessories. Each headlamp is fused separately for both dipped and main beam, so there are four in total fuses. I cannot tell you the fuse numbers or how many down from the top they start as my car is about ten miles away at the moment, under cover. Hope this helps.

[Allan NZ P5b]

Found a very cool relay module called a headlamp relay made in Japan.
It contains 2 relays and 2x30amp fuses. Designed to be mounted close to lights 1 each side with new feed to power lights feeding in then out via relay and fuses to main and dip. Common ground and relay control from existing feeds for high and low beam. Draw is .25 of an amp for relays, I will replace fuse box fuses with 5 amp fuses This should protect all of the lighting circuit, Dash switch, Floor dip switch, indicator high beam flash switch, and column headlamp switch that cuts of headlamps for fog light usage from high loads. I think I will take new feed for lights direct from starter.
Best of all I can get for only NZ$10.00 about 3 pounds each.

Regards

[Deleted]

???Why are these so cheap and readily available outside the UK

[Allan NZ P5b]

I don't know?
I have had it explained several ways over the years.
1) we are such a small market our supliers often get the best buy rate as if buying huge quantities as the manufacturer has no other suplier to make unhappy with pricing differances.
2) We are a Pacific rim country and as such a lot of Asian counties products are very avaliable. used to be rubish but now some world beating products.
3) We have a very market driven economie almost no duties and import taffifs as no local manufacturing to protect. We sell our good to the world and the best way to negotiate a free trade deal is to open your own boarder to them.
4) the above policy when introduced in the 80's caused a lot of pain as manufactures that weren't competitive on the world market failed but now what is left are very competitive in world terms.
And the rest we import at good prices.

Regards