Factory headlight wiring vs. new headlight harness (2 Viewers)

[Eurasiaoverland]

I'm no automotive electrician, and not sure it's relevant to this discussion, but remember the Toyotas are negatively switched. From memory there is always power on both high and low beam at the back of the light and the factory relay switches the ground.

Thanks, I had heard of that but was not clear on what it meant. As a (rather poor) physicist of sorts, it's second nature to me that electrons flow from negative to positive so I cannot get my head around the electrical engineer's idea that current flows from positive to negative and that a 'negatively switched' circuit has the switch downstream of (for example) the lamp. Anyhow, thanks for the tip!

Back to the relay question; in my BJ60 at least, unless there is a relay in the headlight switch on the steering column (which I am pretty sure is just a regular switch), there is only one relay for the headlights, so at least one circuit is switched by the switch.

Therefore, the answer is: it is definitely better to use a dedicated aftermarket light harness... and that is what I am going to do.

In a parallel thread I am looking at adding a relay-swtiched rear fog light to my car, using the unused push-button 4WD actuation circuit. This is another example of a strange use of a relay where only one of the VSVs is switched by a relay, and the other by a switch. Still seems odd to me.

 

[beatle_bayly]

I believe manufacturers use negative switching for increased safety (and maybe to reduce the amount of wiring?)

Yes, use a dedicated harness but that's only for the heavy current section from the battery to the relay to the lights. Keep the stock harness in place (for originality) and use it to switch the relay. If you do it wisely, you should be able to quickly return the system to stock setup by pulling a few plugs (if your new relays were to fail for example).
And you really should have the LH and RH low beams as separate circuits. That way you don't lose all illumination if one circuit fails.

From memory, my 60 had a large Ingrams headlight relay box installed with one circuit for LH low, one for RH low, and one powering both high beams. Plenty of modern versions on Ebay etc for ~AUD$40

 

[CruiserTrash]

Heres one that will blow your mind

View attachment 3303657

This relay handles hi beam, low beam, high beam flash and drives a quad round lamp setup with two round lights per side, inners being high only and outers hi/lo.

What is this quad round lamp setup you speak of? Some unholy cross between a 60 and 62?

 

[Eurasiaoverland]

I believe manufacturers use negative switching for increased safety (and maybe to reduce the amount of wiring?)

Yes, use a dedicated harness but that's only for the heavy current section from the battery to the relay to the lights. Keep the stock harness in place (for originality) and use it to switch the relay. If you do it wisely, you should be able to quickly return the system to stock setup by pulling a few plugs (if your new relays were to fail for example).
And you really should have the LH and RH low beams as separate circuits. That way you don't lose all illumination if one circuit fails.

From memory, my 60 had a large Ingrams headlight relay box installed with one circuit for LH low, one for RH low, and one powering both high beams. Plenty of modern versions on Ebay etc for ~AUD$40

That's good advice, thanks.

I have three circuits in the Koito harnesses - one for each pair of filaments (outer main, outer dipped, inner main), hence three relays. This is enough redundancy for me and to be honest, I've only once had a relay fail on me (and that was for the starter) but still keep a few spares when I travel.

 

[Seth S]

What is this quad round lamp setup you speak of? Some unholy cross between a 60 and 62?

Saab 99. There were a few cars that ran the 4 round light config including Volvo, BMW, Mercedes etc. I don't know how their wiring and relays worked though. The Saab setup is nice as there is a headlight switch for off, parking, on on the dash and then the stock on the column handles flash to pass (headlights on or off) and hi/lo switching.

 

[CruiserTrash]

Saab 99. There were a few cars that ran the 4 round light config including Volvo, BMW, Mercedes etc. I don't know how their wiring and relays worked though. The Saab setup is nice as there is a headlight switch for off, parking, on on the dash and then the stock on the column handles flash to pass (headlights on or off) and hi/lo switching.

View attachment 3306168

I see. I thought you meant a Cruiser. Never seen a Saab like that, though - pretty cool!

 

[Seth S]

I see. I thought you meant a Cruiser. Never seen a Saab like that, though - pretty cool!

They were 69-84 production though USA only got them 69-80.

 

[1973Guppie]

Toyota makes an upgrade kit for this, forget the part number. Comes with bulbs, relays, fuses and harness. Plug and play. Mount relays and fuses somewhere.

have a part #?