[offroader]

I have just installed some driving lights and cannot get them to dip along with the high beams.

I have used a vampire clip to tap the (red) high beam wire as per instructions. The lights work fine but I don't really want to have to reach down and switch them off everytime there is an oncoming vehicle. Has anyone managed to install driving lights so they dip when the high beams are off?

 

[bbottomley]

A few loosely connected thoughts, uncertain since it's not clear exactly where you tapped or exactly how your Forester is wired. Lights do tend to be different in different national markets.

In general, Subaru wires the headlights so that left side and right side each has its own fuse. Each of these power wires connects to the common terminal on its dual filament H4/9003 bulb (or to an equivalent common connection on Foresters that use separate high and low beam bulbs). The high or low beams are selected by grounding one or the other of those dual filaments, through switches, relays, and various other circuitry. "Low side switching" it's called. You can see a representative diagram at this post.

The instructions that come with many aftermarket lights (fog, driving, etc.) often assume that your vehicle employs "high side switching," where the power is switched before it gets to the bulb, and the other side of the filament is connected directly to ground. Those instructions aren't right for a typical Subaru. I can visualize a situation where they would produce exactly the situation you're encountering.

Absent any more specific information about your configuration, the most reliable way to switch driving lights so that they follow the high beams would be to connect a relay coil directly across the high beam filament on one of the headlight bulbs and to power the driving lights through the contacts on that relay. That way you're not making any assumptions about what's + and what's ground. The relay will do exactly what the high beam does.

If indeed you have H4/9003 bulbs, the proper connections would be the two that are opposite each other.

 

[offroader]

I've taken some pictures. I followed the wiring instructions that came with the harness and put a tap onto the red wire which goes into the HB3 high beam globe. The red clip in the photo is the tap. Clearly as has been mentioned, the standard wiring procedure does not work on Subaru's. Auto electrics is not my strong point, you might need to speak in layman's terms.

 

[bbottomley]

HB3 is a single filament bulb for high beam only, but a good bit of what I wrote is still applicable.

Check out my relay tutorial for more specific info, but we can probably talk through it right here.

Look at the 4 contacts on the relay. Two are parallel to each other; they're the coil. The other two are perpendicular; they're the contacts. Here's how the relay works: Put power to the coil and it closes the contacts.

Your lights are probably wired so that power comes from the battery through a fuse and a switch to one of the contacts, and then out the other contact to the driving lights. The other side of the lights would connect to ground.

So far, so good. The problem involves how the coil is wired. You said that you ran a wire from the high beam bulb to the relay. I assume that this went to one of the coil terminals. What is connected to the other coil terminal? My guess is that it's grounded, and that would be the cause of your problem. If that's how it is, disconnect it from ground and connect it to the other terminal on the high beam bulb.

Now you have the relay coil in parallel to the high beam light. They both go on at the same time.

(It's also possible that the switch might be in the relay circuit, not the power circuit. If so, that complicates things a little bit but not much. Let me know if that's what you find.)

 

[offroader]

Attached is a wiring diagram of what I've done. If I attach the (right side diagram),earth wire to the other wire on the HB3 will this do the trick?

 

[bbottomley]

That's what it looks like to me. The "single black" seems to be the other side of the relay coil, and the diagram definitely assumes high side switching on the high beams.

It is a little hard to visualize how the relay is configured. It looks like a normal Bosch relay from the pictures, but the diagram doesn't show the typical terminal configuration. But the wiring all supports our analysis.

Go for it!

 

[offroader]

Yahooo! it worked. :banana: Driving lights now dip with high beams.

Thanks very much for your patience, expertise and help! I was pulling my hair out over this.

With gratitude,

offroader.

 

[bbottomley]

I'm glad it worked out for you. That's great!

You're not the first person to get caught by installation instructions that won't work on a Subaru.

 

[AK Don]

Driving Lights installation

I just installed a pair of Light Force driving lights on my Forester and first of all I have to say that it would not have been possible without all the helpful information I've found here. Like others have said before, with the low-side switching the installation instructions were useless.
After reading these posts, several times, I finally figured it out. And, I came up with a clean way that I can turn on my driving lights with high or low beams.

Why would I want driving lights with low beams? Light force sells optional covers so I can diffuse the light and turn it yellow if I want...using as fog lights or snowy conditions. In this mode I would want to run with low beams and perhaps even use the OEM fog lights too. You could use a similar set up if installing fog lights and you wanted to have the option to use them with the high beams. The point is, it's my choice.

The answer is a 3 position switch, On-Off-On. In one position, it connects the high beam ground to the relay. In the other, it connects the low beam ground to the relay coil. The other connection to the coil comes from the common 12v supply.

I've attached a diagram based on the excellent diagram included in other posts here...the one that helped me figure it all out.

 

[roger_ramjet]

Im still a bit confused...

Hi
I'm plainly a complete numpty, but all this electronica really doesn't make sense to my aging brain.

I've read through this post and I have a Hella wiring kit diagram which suggests, as far as I can tell, exactly the same setup that offroader posted. (Man, for fastidious Germans those wiring diagrams suck don't they?)

So I think...

bbottomley says:

"If that's how it is, disconnect it from ground and connect it to the other terminal on the high beam bulb."

...Which simply means attach that other wire (the 'single black'- which is Blue in my wiring kit...!) to the HB headlight black wire so the 'coil' inside the relay now runs in parallel.

Now this would mean;
a) the only Earth attached is now the one direct from the aux driving lights.
b) I have to tap both the red and black wire in the back of the main HB light.

thus:
"Now you have the relay coil in parallel to the high beam light. They both go on at the same time."

If my interpretation is correct I'd greatly appreciate a response.


Now, I have one (actually two) other issue with my driving light switch. It's one of those backlit jobbies with three prong outlet. One to relay, one to ground and one to "Power for Switch 12V" - I assume this means the aforementioned red wire in the back of the high beam headlight?

There are some tiny, tiny illegible symbols on the back of the switch, which one would be the ground?

If I'm modifying the relay setup as above, then do I actually send it to ground from the back of the switch, or somewhere else?

And, if I inadvertantly reverse any wiring will I blow the relay or my headlights or anything else, or it just won't work? (In which case I'll just pop off to the auto elec and get him to do it....)

Apologies for my confusion....I'm sure you guys are weary of going over this time and time again.

thanks
R

 

[bbottomley]

Quick reply as I'm traveling at the moment and writing from a restaurant after lunch. It sounds like you're on the right track. I'll write more tonight.

Meanwhile, you might find some useful info at this post: http://www.subaruforester.org/vbulletin/f85/snippets-electrical-information-56400/#post626026

 

[roger_ramjet]

ok, think I got it now...

Thanks Mr bb

I followed through a few of those threads and think I may have found my answer here from MudRunner, he has exactly the same wiring setup as me (and one of those stupid backlit switches):

http://www.subaruforester.org/vbulletin/f85/wiring-hellas-subarus-ground-switching-63272/

As it happens, I've discovered a plain (unlit) unused switch on my dash which must have been for the previous owners lights, it only has two prongs so I simply can't go wrong

Now I have to admit I haven't actually plugged anything in yet, so I haven't confirmed any of this, but the sun is shining today and I can go and give it a test run in the driveway.

Have also discovered the pre-packaged wiring kit from Hella assumes the the drivers side is on the RHS (when looking at the car from the hood), my batt is on the RHS but in OZ the steering wheel is on the opposite side, so I'm going to have to go and buy a whole new set of wires and connectors to get the run length back into the dash switch on the opposite diagonal. :icon_sad: (gee I hope that makes sense...)

I'll post back when I've got it running, I know you're all waiting with bated breath on the outcome. :icon_wink:

cheers
R

 

[Arnie_1]

Resurrecting this old thread, hoping for some input. I recently installed a set of Hella FF500 driving lights on my 2002 SG Forester. Followed the wiring suggestions from various threads. Lights are wired to only turn on using the high beam stalk. Not using a switch. They work perfectly fine. However, I have an odd issue, the lights are causing the instrument cluster to power down briefly. Initially, it was just the trip computer resetting to zero at every start. On a drive today I noticed that the speedometer dropped to zero, then fired up back up immediately. Was like a slight hesitation in its operation. If I disconnect the relay from power, the issue is gone.

Any ideas or suggestions on why the instrument cluster is being affected by having the relay tapped into headlights? It's really odd. I thought it might be a bad ground, but I rechecked and they are solid (from the driving lights).

Appreciate any ideas. Cheers!

 

[Bjornonline]

Resurrecting this old thread, hoping for some input. I recently installed a set of Hella FF500 driving lights on my 2002 SG Forester. Followed the wiring suggestions from various threads. Lights are wired to only turn on using the high beam stalk. Not using a switch. They work perfectly fine. However, I have an odd issue, the lights are causing the instrument cluster to power down briefly. Initially, it was just the trip computer resetting to zero at every start. On a drive today I noticed that the speedometer dropped to zero, then fired up back up immediately. Was like a slight hesitation in its operation. If I disconnect the relay from power, the issue is gone.

Any ideas or suggestions on why the instrument cluster is being affected by having the relay tapped into headlights? It's really odd. I thought it might be a bad ground, but I rechecked and they are solid (from the driving lights).

Appreciate any ideas. Cheers!

This could be caused if your wire your relay wrong. I've got an example from a high side switched vehicle: The vehicle was equipped with three aux lights, working fine. Relay broke down at about the same time as the next service, so the workshop was instructed to replace it. However, they put in a relay with another pin layout: normally you would connect 85 to the trigger and 30 to battery, but in this case battery became connected to 85, and the trigger to 30. This resulted in a relay that was always on, taking power from the trigger, which in this case was the high beam light. So this light had to pull not only its own bulb, but three more. Just glad it didn't fry anything - but ofcourse it showed: the lights were very low on power. However, I don't remember any flickering on the instruments, but then again this was another brand (VW).

TL;DR - check if you got the wrong relay.