Install Sunyee Cree 126W light bar - SG II Forester

Yeah, that would complicate things!

The 126W light bar draws 8.45A, so a secondary relay is absolutely necessary to avoid overloading the high beam circuit.

The secondary relay can be connected as per conventional wisdom, switching the negative of the light bar.

I dont understand why you need 2 relays. The first relay takes current from the battery to the lightbar, whats the second do?

^ the second relay switches the 8.85A load on the high beam ground wire (i.e. the current draw of the light bar negative circuit). This makes the additional load on the headlight common ground wire a mere 160mA instead.

The second relay is switched by the vampire wire on the negative high beam light wire to terminal 85, and is activated by the white switching wire on the light bar ON/OFF switch jumpered to terminal 86. and this relay is earthed at any convenient point from terminal 87 (currently a bare wire poked into the battery negative terminal).

Terminal 30 on the second relay is wired to the earth wire on the supplied relay, which is not earthed. From that common terminal (black wires), another wire runs to the light bar negative using the supplied loom.

The supplied relay is activated by the vampire wire on the high beam positive wire (and also switched by the light bar ON/OFF switch). This relay switches the positive power to the light bar, not both + and -, as supplied.

The red wire on the supplied switch goes to the positive vampire wire (red) on the high beam bulb.

I have drawn a wiring diagram, but have not yet made up an ancillary wiring loom - i.e. it's still a rat's nest ... BUT, it works, and nothing else did!

Now to have my breakfast, and a shower!

Have been learning about relay on the internet...

The HL relay in my MY06 Forester is a 4 pin one - does it mean the high beam trigger (wire) is somewhere between the relay and the headlight unit?

Still learning...

^ PS, your car has two relays. One for each headlight unit. Two pins switch the high beam, two switch the low beam. The relays appear to be remotely switched/triggered.

Id has checked out what I have done this arvo, and agrees that it is possibly the only way to do it.

I will try to get my wiring diagram posted tonight or tomorrow morning.

The current drain by the light bar is now only about 160mA on each of the positive and negative high beam wires.

Dual relay and cabin switch wiring diagrams

Gidday PS

This is what I have done. It works properly - i.e. only comes on with HB, and nothing else.

Wiring diagram:



Full size printable image:

https://canopuscomputing.com.au/gallery2/d/18123-2/E-510_JAK_2015-_6278294+copy-Large.jpg

Wiring layout for engine bay:



Full size printable image:

https://canopuscomputing.com.au/gallery2/d/18127-2/E-510_JAK_2015-_6278295+copy_Large.jpg

Sorry about my crappy drawings, but I hope this helps you.

Some photos of the very roughly fitted light bar ...





It has to be adjusted for level and square yet.

Ratbag said:

Gidday PS

This is what I have done. It works properly - i.e. only comes on with HB, and nothing else.

Wiring diagram:

Full size printable image:

https://canopuscomputing.com.au/gallery2/d/18123-2/E-510_JAK_2015-_6278294+copy-Large.jpg

Wiring layout for engine bay:

Full size printable image:

https://canopuscomputing.com.au/gallery2/d/18127-2/E-510_JAK_2015-_6278295+copy_Large.jpg

Sorry about my crappy drawings, but I hope this helps you.

Some photos of the very roughly fitted light bar ...

It has to be adjusted for level and square yet.

Click to expand...

Well done Ratbag. You made it! And thanks for sharing the diagram.

^ Thanks, PauSum.

And you are more than welcome.

I plan to start on the permanent wiring tomorrow. Ripped a dead PC power supply to bits and cut off the main power loom just now. Makes for lots of multi-coloured, heavy, high amperage bits of wire. These should be easier to follow and assemble than my all white wires I have used for my project to date! :iconwink: :lol:.

I also need to make a bracket to hold both relays and provide an earth point for the secondary relay. The main (supplied) relay must not be earthed.

Ratbag,

I need your help to understand the diagram (sorry I am really not good with electronic)

- the "40A supplied Relay" in your diagram is the relay that comes with the light bar?
- from your diagram, your second relay is a normal open 4 pin relay?
- In the wiring layout for engine bay diagram, the cabin switch and fog switch are linked by a "P" - what does this mean?
- In the relay that comes with my (20in) lightbar, there are numbers (87, 30, 85 and 86) at the pins and how are they correspond to W, B R1 and R2 in your wiring diagram?

sorry that's for it at the moment...

Hi Ratbag,

I understand the point of using 2 relays to separate the current drawn for high beams from the current drawn for the light bar. That part makes sense to me.

What I don't understand is why aren't you running 1 battery wire straight to the light bar and switching the other wire only? Why do both go through the light bar relay and not just 1 to keep design simpler? I get the feeling you're shoehorning positive switching into a negative switched car...

Anyways, if it works...

Gidday Pedro

pezimm said:

Hi Ratbag,

I understand the point of using 2 relays to separate the current drawn for high beams from the current drawn for the light bar. That part makes sense to me.

Click to expand...

I'm glad it does to someone, mate ... :iconwink:
It took plenty of pain and suffering for me to work out how to do this!

What I don't understand is why aren't you running 1 battery wire straight to the light bar and switching the other wire only?

Click to expand...

Because that leaves a current draw of 8.85A (or a little more) being drawn off the light assembly circuit at a different point. Because of how Subaru have wired my car (common ground at the h/l assembly = 120W, plus two switching wires that won't switch anything), and my inability to find the high beam relay switch wire either under the dash or in the engine compartment, it became necessary to put both light bar wires through relays. Unless one has a double pole relay to hand, this necessitates two cascading single pole relays, with one switching the other, and the cabin switch switching them both.

Why do both go through the light bar relay and not just 1 to keep design simpler?

Click to expand...

It doesn't work ...

I get the feeling you're shoehorning positive switching into a negative switched car...

Click to expand...

More or less right. A single relay doesn't work. It leaves a 9A current being pulled off whichever high beam wire is used for switching. Also, switching from just one of the high beam wires, whether positive or negative, leads to some very strange results!

Anyways, if it works...

Click to expand...

Yes, it does.
And it draws a whole 160mA from each of the high beam wires. Somewhat better than being at least 4A over the fused rating of the whole assembly, let alone the current draw from any individual wire/s within that circuit.

Gidday PS

PauSum said:

Ratbag,

I need your help to understand the diagram (sorry I am really not good with electronic)

- the "40A supplied Relay" in your diagram is the relay that comes with the light bar?
- from your diagram, your second relay is a normal open 4 pin relay?
- In the wiring layout for engine bay diagram, the cabin switch and fog switch are linked by a "P" - what does this mean?
- In the relay that comes with my (20in) lightbar, there are numbers (87, 30, 85 and 86) at the pins and how are they correspond to W, B R1 and R2 in your wiring diagram?

sorry that's for it at the moment...

Click to expand...

Principles are the same. Use the red wire from the supplied switch to connect to the red wire at the high beam light connector. Use the supplied relay to switch the positive wire from the battery to the light bar (red wire from light bar).

Cascade this relay to a secondary relay. Switch this relay using a wire from the negative wire at the high beam bulb connector. Use this relay to switch the negative (black) wire from chassis earth to the light bar.

The wire marked 'P' connects the OEM driving light switch to the instrument panel lighting circuit via that connection on my fog light switch.

I will modify the photos posted and re-post them today.

Basically, on your supplied relay:

Red fused wire from battery goes to terminal 87 on your supplied relay.

Red wire to light bar connects to terminal 30.

White wire from your mushroom cabin switch connects to terminal 86.

Terminal 85 connects directly to earth (not the black wire connected to your cabin switch). Test this latter by brushing on battery earth with everything else connected and switched on and the headlights on high beam. When doing this, the light bar should go from off to on. Check that the cabin switch is ON if it doesn't.

Terminal 86 and 85 need to observe the same polarity as the load (light bar) on my secondary relay, and the earth wire on my primary relay cannot be connected to earth.

Do not connect either of the two light bar wires to any chassis earth. Both must be switched via the relays.

The black wire from the cabin switch is not used.

See also my explanation of the logic of all this in my reply to Pezimm immediately above.

It might be possible with your supplied relay to use a single relay solution, by connecting the light bar red wire direct to the battery (with the in-line fuse in this wire), then switch the negative wire to the light bar via the supplied relay. However, this still leaves other potential problems.

This other solution was not available to me as the relay supplied with my light bar has all the wires hard wired internally differently from a standard relay. Mine is almost, but not quite, a double pole relay.

Photos of rat's nest light bar wiring

Gidday Folks

Some photos of my rat's nest light bar wiring.

The only connections that are tight are those to the supplied relay and switch, the positive battery terminal, the light bar itself and the vampire connectors on the high beam positive and negative wires. Everything else is loose. That is, only pure thoughts and good wishes are holding about half the wires in place.

I intend to rectify this today and make a bracket to securely mount both relays side by side between the engine bay fuse/relay box and the firewall .

Hopefully I will have my Fox operational again this arvo, and a working light bar :biggrin: .

One of the problems - the supplied relay is almost a dual pole relay, but is not quite. The chassis earth and earth (negative) load wire to the light bar are jumpered to the same terminal on the relay. This effectively prevents any kind of negative switching ...



The rat's nest! I will replace all the white wires with colour coded wires as I install all this permanently.



The vampire wire crimp terminals attached to the high beam positive and negative. The red vampire lead goes to the supplied cabin switch. The black vampire lead goes to the switching terminal on the secondary relay. Each of these wires is only drawing around 160mA from the headlight circuit.



The light bar connections. I had to crimp blade connectors to the light bar side, as it came wire bare wires. I intend to wrap these in insulating tape once everything is complete.



Heavy gauge fused red wire from supplied relay to battery positive.



Earth (Negative) wire from switching side of secondary relay (terminal 87) to battery negative. This will be secured to chassis earth via the mounting bracket.



The 30+ y.o. 30A Hella relay that I have used for the secondary relay. The wires are just poked into the blade connectors ATM ... Everything can require a bit of jiggling to work :lol:.

Terminal 85 connects to the black (negative) vampire wire on the headlight high beam negative (grey/black wire). This provides the switching current (~160mA)

Terminal 86 connects to the switching wire (white) on the supplied primary relay. This is the 'output' side of the switching circuit/solenoid energiser. Connecting the secondary relay switching circuit this way ensures that the solenoid is not in an ALWAYS ON condition. It switches off with the ignition, or if the cabin switch for the light bar is switched off, or the high beam lights are switched OFF.

Terminal 87 connects to chassis earth (i.e., it is the other pole of the relay switched circuit for the light bar negative wire).

Terminal 30 goes to the light bar via the black siamesed terminal on the supplied relay for no other reason than it is a convenient attachment point. The other one of this pair of siamesed wires runs to the light bar black (negative) wire.

That is to say, the switching circuit is across terminals 85 and 86. The light bar current is drawn across terminals 30 and 87.

This photo also shows the internal wiring of the relay embossed on its case. Simple, but useful.



A photo of the relay from a different angle showing the terminal connectors. These wires are just pushed in to place ATM - i.e. not crimped or soldered ...



I expect things to be a little bit tidier by the end of the day ... :iconwink: :lol:.

It's done.

It works.

The light bar makes the high beam lights look like candles ... :biggrin: :lol:.

All that's left to do now is to feed the wires from the dash switch through the firewall grommet and connect that switch to the instrument panel lights.

The cabin switch wires terminate on tunnel connector plugs. Their corresponding wires in the engine bay also terminate on tunnel connector plugs, and a tunnel connector.

Now all very neat and tidy. Will post some photos of the finished job later. Got to put my tools away ...

Nice work!

Thanks, Id.

Also thanks for checking everything over for me yesterday :biggrin:.

Here is a photo I missed out of the previous sequence. This is where the relay bracket will be mounted.



Photos of the (mostly) finished job to follow after dinner.

Thanks for showing me the lightbar! i might have to pick one up its a well made product and a steal at that price.

^ Terrific to finally meet up, mate. Don't be a stranger ... :iconwink: :ebiggrin:.

The light bar's bloody fantastic value at $89.96 delivered. Thanks go to PauSum for putting me onto it .

Here are some photos of the (almost) completed setup.

Vampire wires attached to each side of the high beam bulb:



Bracket for relays:



Relays mounted:



OEM driving light switch wired up to light bar loom:



Tunnel connector to allow disconnection of the cabin switch:



OEM cabin switch showing light bar in ON position:



The light bar in action, compared with the high and low beam lights ...



Exposed using the high beam light for metering ...



Tomorrow I just have to feed the cabin switch wires through the firewall, ditto for the UHF aerial. Then put the dash back together.

Ratbag said:

It's done.

It works.

Click to expand...

Ratbag said:

The light bar's bloody fantastic value at $89.96 delivered. Thanks go to PauSum for putting me onto it .

Click to expand...

Luckily it's a good product :lol::lol:

Ratbag said:

Here are some photos of the (almost) completed setup.

Click to expand...

Really nice work!