Both headlight relays always on

[rickyhils]

 Both relays [green connector and black connector] are always energized whether head light switch is on or off. 1991 Loyale Wagon SPFI FWD. With ignition on/ engine off can hear "click" when relay connected. There has been no messing with the electrical by me, and previous owner bought it new and only took to certified service shop. 

Edited July 12, 2020 by rickyhils
clarify wording. Info is same.

[Step-a-toe]

With IGN on you find they are energised but not always as in IGN off, door closed, locked and cabin empty?

Might well be normal but I don't like idea of being energised all the IGN on time, but guess after 30 years they not failed?

I have rigged up same relays to work only when towing to boost the rear indicators from 8.6V to battery voltage so my trailer LED indicators work. All three Brumbies if mine had trouble making LED trailer blinkers bright until B3 was sorted. Thinking I now may have gone to a lot of trouble for nothing, afterall our ecu and FP relays are always on with IGN !

Our headlight switches switch Earth side, think no relays Earth side just positive

Edited July 12, 2020 by Step-a-toe

[rickyhils]

All looks OK with my 1991 Loyale head light circuit. I am on an uphill learning curve here, but slowly grasping a few bits at a time.

I have an official 1991 Loyale set of circuit diagrams. The two HL solenoids are always powered up when ign is ON, so full positive power is always supplied to both HLs (head lights). It is the HL switch that completes the circuit to ground. I would have thought that the switch itself need be capable of the higher amperage, as it completes the circuit to ground. I am under-qualified here I know.

Another notable find is this:  When a HL solenoid is out (or a fuse is out), it is the DASHBOARD HIGH BEAM INDICATOR BULB that will still transfer some low watt voltage on over to one of the HLs, causing a very dim glow to happen on one of the HLs. I had previously thought that I had some serious wiring problems when I first saw that some months ago. So not a problem there.

My brain is sweating trying to slog through all of this. But it is a "good" slog.  ha ha ha

 

[Ionstorm66]

The column switch connects ground. The relays are just so your headlights are off when the key is off.

It is a common modification to lots of old cars to add a relay for the headlights to preserve the switch. Switches are getting hard to find for lots of older cars. It's better to add a relay now, which dramatically reduces the current. Makes the contacts in the switch last much much longer. You should do the same to the starter line. The starter solenoid draws a fair bit of current, and the key switch can wear out.

 

It's an issue on all contact based DC switches. With AC there is a zero point to extinguish the arc, not so with DC.

[Step-a-toe]

Ricky, you keep calling relays "solenoids" you gonna make other brains sweat

Yeah, I thought no relay on switching side was odd but leave it as they were for 30 years

[rickyhils]

4 hours ago, Ionstorm66 said:

The column switch connects ground. The relays are just so your headlights are off when the key is off.

It is a common modification to lots of old cars to add a relay for the headlights to preserve the switch. Switches are getting hard to find for lots of older cars. It's better to add a relay now, which dramatically reduces the current. Makes the contacts in the switch last much much longer. You should do the same to the starter line. The starter solenoid draws a fair bit of current, and the key switch can wear out.

 

It's an issue on all contact based DC switches. With AC there is a zero point to extinguish the arc, not so with DC.

Good idea. Original relays are the 056708-5260. But any relay that can handle 20 amps should be OK.

[rickyhils]

2 hours ago, Step-a-toe said:

Ricky, you keep calling relays "solenoids" you gonna make other brains sweat

Yeah, I thought no relay on switching side was odd but leave it as they were for 30 years

Got it. They are RELAYS from now on! But is it not better to add relays to both head light switch and starter switch?

[DaveT]

I haven't had a problem with the OEM headlight wiring / switches.  The starter switch / or it's wiring yes.  i added a relay for both of my cars.   The current is higher in the start wire, and the load is inductive, which is far worse on the switch than headlamps.

[rickyhils]

3 minutes ago, DaveT said:

I haven't had a problem with the OEM headlight wiring / switches.  The starter switch / or it's wiring yes.  i added a relay for both of my cars.   The current is higher in the start wire, and the load is inductive, which is far worse on the switch than headlamps.

OK. So a relay rated at 20 amps would do the job for the starter relay?

And, on the headlight circuit, the relays send full positive voltage/amperage when ign is ON. But the connection to ground is of a lighter gauge wire isn't it? Is it that the final connection to ground is of a lower amperage? I am not educated in this. Thanks

[DaveT]

I'll have to see what I used...  It's been in there a long time now.
Or check what fusible link / fuse is in line with the ignition switch.  That's a starting point for a minimum.  The starter solenoid is thirsty for amps.  Relay contacts are rated in different ways - resistive is common, and the easiest on a contact.  Lamps and inductive loads are much harder on contacts.  Typically contacts are derated from the resistive rating for a given contact when used for incandescent lights or inductive loads

.

[rickyhils]

On 7/13/2020 at 10:15 PM, DaveT said:

I'll have to see what I used...  It's been in there a long time now.
Or check what fusible link / fuse is in line with the ignition switch.  That's a starting point for a minimum.  The starter solenoid is thirsty for amps.  Relay contacts are rated in different ways - resistive is common, and the easiest on a contact.  Lamps and inductive loads are much harder on contacts.  Typically contacts are derated from the resistive rating for a given contact when used for incandescent lights or inductive loads

.

I looked up what inductance is. Yeah, the solenoid winding and the magnet at the starter motor will cause a huge amperage load. That amp load probably backs off a bit after gear is engaged and spinning. There must be a high amp connector inside that clamps closed to actually spin the motor. Like on my Honda.  But to operate the moving solenoid is enough reason to add a relay.

[DaveT]

Inside the starter - are 2 parts -  The solenoid, and the motor.  [some also have a reduction gear]  The solenoid is what is powered by the ignition key.  It is a powerful electromagnet.  I never measured one, but anything between 20-50 amps would not surprise me.   It pulls a plunger that is connected by a lever and fork, which pushes the pinion gear out to engage the edge of the flywheel.   At the same time, the solenoid also moves a big contact that closes the circuit to put battery + to the starting motor.  This motor can draw hundreds of amps, depending on how stiff the motor is [from cold, etc.]

The hard part of switching inductors is not on the make, it's on the break of the circuit.  Inductors "fight" a change in the amount of current flowing through them.  So on closing the circuit,  the current has a lagging / "slow" rise.  Energy is stored in the resulting magnetic field.   On the break, the magnetic field collapses, which causes the winding to act like a generator - and because the circuit is open, the voltage shoots WAY up, which makes it harder for a switch to interrupt.  A little bit of the contact is burned away each time this happens.

  This rapid field collapse effect is also why points ignition fires when the breaker points open.  In electronic ignition, a FET turns off rapidly, causing the same effect.

[rickyhils]

3 hours ago, DaveT said:

Inside the starter - are 2 parts -  The solenoid, and the motor.  [some also have a reduction gear]  The solenoid is what is powered by the ignition key.  It is a powerful electromagnet.  I never measured one, but anything between 20-50 amps would not surprise me.   It pulls a plunger that is connected by a lever and fork, which pushes the pinion gear out to engage the edge of the flywheel.   At the same time, the solenoid also moves a big contact that closes the circuit to put battery + to the starting motor.  This motor can draw hundreds of amps, depending on how stiff the motor is [from cold, etc.]

The hard part of switching inductors is not on the make, it's on the break of the circuit.  Inductors "fight" a change in the amount of current flowing through them.  So on closing the circuit,  the current has a lagging / "slow" rise.  Energy is stored in the resulting magnetic field.   On the break, the magnetic field collapses, which causes the winding to act like a generator - and because the circuit is open, the voltage shoots WAY up, which makes it harder for a switch to interrupt.  A little bit of the contact is burned away each time this happens.

  This rapid field collapse effect is also why points ignition fires when the breaker points open.  In electronic ignition, a FET turns off rapidly, causing the same effect.

And I suppose that on a smaller scale, even the EGR solenoid can cause voltage spikes when it lets off. That's why I wired in a dummy resistor load instead of the EGR solenoid.

[Loyale 2.7 Turbo]

On 7/13/2020 at 2:36 PM, rickyhils said:

... My brain is sweating trying to slog through all of this. But it is a "good" slog.  ha ha ha

 

I bet you can find Useful information, in this Writeup:

~► https://www.ultimatesubaru.org/forum/topic/87523-how-to-swap-the-old-roundie-relays-with-standard-bosch-relays/

Kind Regards.

[rickyhils]

3 hours ago, Loyale 2.7 Turbo said:

 

I bet you can find Useful information, in this Writeup:

~► https://www.ultimatesubaru.org/forum/topic/87523-how-to-swap-the-old-roundie-relays-with-standard-bosch-relays/

Kind Regards.

THanks

[DaveT]

Yes, the small valves / solenoids have the same effect.  Smaller power in, so it is smaller than the big ones.  The circuits that drive these have to be designed to give that spike somewhere to go, so it is not an issue.  Typically,  a diode is wired across the coil in the direction that it does not conduct when power is applied to actuate it.   When the power is switched off, the resulting induced current goes through the diode, so no high voltage is produced.