Topic: Making the DBG 'Convert Side-Marker Lights into Turns' mod work with LEDs

[TomatoSoup]

Way back in the past I had done the Simple DeepBlueGXP side-marker mod. Per: http://www.solsticeforum.com/forum/f62/how-convert-side-marker-lights-into-marker-turn-signals-48817/
It just worked, so I never looked into actually how it worked and I forgot about it.

However, this weekend I finished coverting all my external lights to LEDs (well, except for my reversing lamps - yet).  Upon doing that, I found that the DBG mod no longer works when the parking lights are off (i.e. during the daytime).  Arggh.  So then I delved into HOW the mod works, and what I needed to do to make it work again!

I'll create this thread as three posts:

• The rest of this intro post will be to explain how the DBG mod works and why it has issues with LEDs.
• The second post will show what you need to do if your are just converting your side-markers to LEDs
• The third post will be what you need to do if you've converted ALL your parking lights to LEDs (probably won't apply to many :-) )

So if you don't care about how the DBG mod works, skip the rest of this and jump to post 2.  Otherwise read on...

So the DBG mod is as follows:



Basically, the side-marker lamp is now connected between the Brown parking lamp +ve supply and the Blue turn signal +ve supply (instead of between the parking +ve and (Black) ground).

Thus, when everything uses OEM filament bulbs, the side-marker lights operate as follows:

• When both turns and parking lights are off, the side-markers are off (obviously)
• When the parking lights are on and turns are off, the Brown wire supplies the +ve voltage, while the Blue wire is grounded through the (low resistance) filament of the front turn signal bulb on that same side, thus the side-marker bulb lights up.
• When the parking lights are on AND the front turn bulb is on, both the Brown wire and the Blue wire are at +ve voltage, so no current flows and the side-marker bulbs do NOT light. When the turn voltage 'flashes' on, the side-markers flash OFF - in opposite phase to the front turn bulb.
• When the parking lights are OFF but the front turn bulb is ON, the Blue wire supplies the +ve voltage, while the Brown wire is grounded through one or more of the (low resistance) filaments of the parking bulbs, thus that same side-marker bulb lights up and in the SAME phase as the front turn bulb.  Note, all front and rear parking light bulbs are wired in parallel, so as long as any one of the bulbs is still a filament (not LED) this mechanism will work.  Only when ALL are converted to LEDs, will it fail - see post 3!

OK, I hope that was clear.  On to fixes...

[TomatoSoup]

OK, so you've converted your side-marker to use LED bulbs and now the DBG mod has stopped working if the parking lights are off... what to do?

Providing, at least one of your front or rear parking lights are still filament-based (if not, see also post 3) you just need to use a bridge rectifier before your LED bulb.  Basically the reason is this... When the parking lights are on, the brown wire is +ve and the blue is ground.  As you know, LEDs are unidirectional and given that they are wired the right way, they will light.  However, when the parking lights are OFF, the voltage reverses, now it's the BLUE wire that is positive (on flash) and the brown becomes the ground, thus the LED(s) won't light!

If you are just replacing the side-marker filament bulbs with LED t10-base bulbs, you MUST use ones that include a bridge rectifier - these are the types that can be inserted either way round and will still work.  If you have the type that can only be inserted one way round (they come with a warning thst says something like "if these bulbs fail to light, just turn them around in the socket") then you are SOL.

If you are custom-converting your side markers (as I did) then you must add a bridge rectifier.  Bridge rectifiers are simply 4 diodes arranged in a diamond pattern and packaged with 4 leads - 1 off each corner of the diamond:



Suitable types can be found at RadioShack (or eBay) such as this one: http://www.radioshack.com/product/index.jsp?productId=20843296

You just wire the two legs marked with the "~" to the socket, and then the "+" and "-" legs to your LED(s).  Here are some photos of my build as examples...

This is the bridge rectifier front and back, leads bent to fit and loosely inserted in the base from an old eBay LED bulb (sacrificed for the cause):

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Then the final connections, soldered to the LED wires and added insulation and heat-shrink:

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[TomatoSoup]

So, finally, you're a hard-core LED-er and reading this 'cos ALL your parking lights are now LEDs.  So now you have no low-resistance filaments to give your side-markers a path to ground when the blue wires are flashing ON. 

OK, so the way around this is to mod the parking light relay in the underhood fuse block, such that the (normally unconnected) OFF contact is wired to a ground point.  Then when the parking lights are off (daytime) the relay is not energised, but the brown wire is grounded through the relay instead of a bulb filament.

The parking relay is number 68 (top right hand corner of the fusebox).  You'll have to pull it; open it up; solder a wire to a contact inside; drill a hole in the case top and route the wire through it; clip the case back together; finally, solder a tab to the free end of the wire.  Then you can replace the relay and connect the wire to a ground point (the middle socket of the empty relay location #39).  Done!

How-to pictures... First, pull the relay (#68) and remove the case by prying the tabs.  It's easy to break these on the outer case, so I used some cut-up 'bubble-pack' plastic to wedge in and free the sides off the clips:

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Then solder a wire to the normally unconnected contact on the relay.  This is the contact at the far end of the relay (away from the coil):

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Drill a hole from inside the top case for the wire to exit:

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Route the wire through the top and clip the relay base and top case back together. Cut the wire to length - about 4 1/2 inches is perfect:

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Solder a suitable tab on the end of the wire.  I used an old mini-fuse leg (mini fuse cut in half and the plastic stripped off):

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Insert the relay back in the fuse box. WARNING: THIS MUST BE INSERTED THE CORRECT WAY ROUND OR YOU'LL BLOW THE FUSE!  The wire should be on the left side, with relay pin 30 (as marked on the bottom) at the top right, nearest the big red positive battery terminal.  Then plug the wire into the socket shown ("Ground Pin") at the middle of the empty relay #39 position:

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Done!

[Sly Bob]

Awesome work TS.   

So if I read this correctly, this mod is only necessary if all turn signal lights have been changed to LEDs?

[TomatoSoup]

So if I read this correctly, this mod is only necessary if all turn signal lights have been changed to LEDs?

Post 3 is only necessary if all PARKING (running) lights have been changed to LEDs. 

If you change the turn signals to LEDs, you'd have to add load resistors anyway to stop hyper-flashing, and they'll provide the path to ground for the turn signal part of the equation.

(Post 2 is necessary if the side-markers are changed to LEDs - whatever the others are)

[elff]

Wow

That's is alot of work

[Sly Bob]

My side marker lights are LED, I'll have to look into this. Really isn't a lot of work Elff when you look at it. I imagine in took longer to put the post together than it did to actually do the mod.

Lot's of great information TS, thanks!

[Critterman]

All my lights are LED except the headlights.  We ran into this problem even with the resistors in place on the turn signal.  We just did away with the blinker mod on the side lights.

[TomatoSoup]

All my lights are LED except the headlights.  We ran into this problem even with the resistors in place on the turn signal.  We just did away with the blinker mod on the side lights.

Yep - you need to follow post 3. 

[Sol Asylum]

One of Critter's electricians had a broken wrist when the LED mod was being done so we didn't try real hard to figure out a solution. 

TS instead of modding the relay would it be possible to just run a ground wire to the corresponding socket in the fuse panel?  That way if the relay ever goes bad you wouldn't have to do anything more than just replace it.

[DeepBlueGXP]

I think the relay mod I originally did would work with the LED mod.

[TomatoSoup]

TS instead of modding the relay would it be possible to just run a ground wire to the corresponding socket in the fuse panel?  That way if the relay ever goes bad you wouldn't have to do anything more than just replace it.

Agggh.  Well, no, unless you want the fuse to blow

The ground wire goes to the relay contact that's only connected when the lights are off.  When the lights are ON, the relay connects the lights to 12V via the fuse.

Anyway, if the relay goes bad you can still just replace it.  You'd just lose you side-marker turn flashing during daytime, until you redo the wire.

I think the relay mod I originally did would work with the LED mod.

Yes, I agree.  And if you're starting out from a blank sheet, maybe that would be easier(?)  Actually maybe not, 'cos you have to buy, wire and mount TWO relays.

[Sol Asylum]

I must be missing something, you solder a wire to a terminal inside the relay then run that wire to ground.  How are you going to blow a fuse if instead of connecting the wire inside the relay you run the wire to where that terminal of the relay plugs into the fuse panel?  You end up with the same circuit you just don't have to mod a relay.

[TomatoSoup]

I must be missing something, you solder a wire to a terminal inside the relay then run that wire to ground.  How are you going to blow a fuse if instead of connecting the wire inside the relay you run the wire to where that terminal of the relay plugs into the fuse panel?  You end up with the same circuit you just don't have to mod a relay.

Oh, I thought you meant to the fuse itself - my bad. 

OK, well that contact is cut off underneath the relay - it doesn't plug in to the panel - so you can't easily solder to it.  But then if you DID, you can't easily run the wire out from underneath since the relay sits set down in the tray.  I would've done it that way if I could, but running the wire out the top was easier.

[Sol Asylum]

I am saying to actually run the wire on the underside of the tray to a connector that would install in the tray in the socket that makes contact to the terminal on the relay.  Use the socket like it was intended and make things look like it left the factory that way.

[TomatoSoup]

I am saying to actually run the wire on the underside of the tray to a connector that would install in the tray in the socket that makes contact to the terminal on the relay.  Use the socket like it was intended and make things look like it left the factory that way.

Unfortunately there is no terminal on the relay (#68) nor a socket on the fuse tray to that (missing) terminal on the relay.  The contact is only accessible from within the relay itself.

In other words, that would be the 5th terminal (changeover contact) on the relay, but it's a 4-terminal (on-off) relay and a 4-terminal socket.

[Sol Asylum]

From the picture it looks like you are soldering to a terminal that exits the case, now I understand.

[Critterman]

I don't.  Can you explain it all again? 

[BigSal]

Critter,

  You are bad !!!

T.S.
 
   Going to try this in a few weeks. Thanks for the text and focused pictures. Don't worry about John, he'd only supervise the job anyway...

Sal