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Discussion Starter #1
I had a 06 3S hatch and after about a year of not being able to see anything in the hatch at night I got a dummy bulb and some Ultra Slim Pre-Wired Surface Mount 12V LED : 5050 SMD from oznium (don't work for for them or get paid by them just a good solid product) and wired them into the hatch. I now have a '15 3 IGT hatch and would like to the same, however everywhere I look I keep seeing horror stories about the RBCM frying and what should be a simple $30 mod turning into a grade A weapons grade clusterf**k.

I have found may horror stories but I have yet to find a success story. Is it possible? Can I not google properly? Can I just drop a dummy bulb in, wire it to my LEDS (maybe add a resistor as well to match old halogen bulb draw)? Please I'm afraid of the dark and the possible monsters hiding in the shadows of my hatch.
 

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I don't see why this isn't possible, you can always buy those festoon bulbs that are adjustable via spring, and then it has a 12v +/- and you can connect the LED to it.
 

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It's also a matter of current draw. This hatchback trunk light is tied into the RBCM which from the wiring diagram shows a 5W bulb which is the one which is installed. If engineering principles hold, I'd reckon they probably designed the RBCM to handle up to 50% more as rated draw. If you hookup more than it can handle I'm guessing that's where all the horror stories are coming from, which are long strips or SMD boards with too many LEDs drawing more than the rated wattage across the RBCM.
 

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It's also a matter of current draw. This hatchback trunk light is tied into the RBCM which from the wiring diagram shows a 5W bulb which is the one which is installed. If engineering principles hold, I'd reckon they probably designed the RBCM to handle up to 50% more as rated draw. If you hookup more than it can handle I'm guessing that's where all the horror stories are coming from, which are long strips or SMD boards with too many LEDs drawing more than the rated wattage across the RBCM.
As a mechanical engineer I 100% agree with this. I just got this car and I'm trying not to break anything yet. I am not putting anything crazy in just 4 to 6 of these little guys https://www.oznium.com/prewired-surface-mount-led
2 in the hatch area and 2 on the hatch door facing the ground and 2 red facing outward (when hatch is open).
 

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I just got VLEDS all around my car now those suckers are bright, pricey but it's quality stuff.
is it enough to light up the whole hatch area though? thats my main issue. The phillips LED's I have in the cabin are bright enough I think. I had much brighter ones I got off ebay but they all flickered or burned out within months. But I will check out VLED
 

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Discussion Starter #7
It's also a matter of current draw. This hatchback trunk light is tied into the RBCM which from the wiring diagram shows a 5W bulb which is the one which is installed. If engineering principles hold, I'd reckon they probably designed the RBCM to handle up to 50% more as rated draw. If you hookup more than it can handle I'm guessing that's where all the horror stories are coming from, which are long strips or SMD boards with too many LEDs drawing more than the rated wattage across the RBCM.
I don't see why this isn't possible, you can always buy those festoon bulbs that are adjustable via spring, and then it has a 12v +/- and you can connect the LED to it.
I don't know why only part of this posted before, but here it is again. I think you are both right. I'm ordering some lights and a dummy festoon . I doubt that I'll hit the 5W mark but I will do a write up with pics and hopefully nothing explodes.
 

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is it enough to light up the whole hatch area though? thats my main issue. The phillips LED's I have in the cabin are bright enough I think. I had much brighter ones I got off ebay but they all flickered or burned out within months. But I will check out VLED
I'll take a picture tonight to give you some perspective on this bulbs. You can't even compare the Chinese LED's to VLED's. These are BRIGHT.
 

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Like you Amal, I utilized a dummy festoon with LumenHID 5050 SMD 8 LED replacement. the 8 LED board fits perfectly in the translucent cover with the dummy festoon sitting on top of it in the connector built into the cover. I've found the brightness has increased to the point that it lights it up approximately 4 times brighter (Visual approximation). Though if you have large stuff in the back, the right side of the trunk will have shadows thrown on it. I considered LED strips, but once again the draw limitation.
I'm considering drawing up a plan to have the dummy light switch in the cover act as a current source for a MOSFET with a 6 V gate signal that will then draw power from a separate fuse. This way the trunk hatch open/close will still allow the LED strips to turn on and off, and also isolate the lighting current draw from the RBCM. 12V from RBCM through a voltage divider down to 6V.
 

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I am seeing several options for the hatch's "cargo/trunk" area light on their web site. Which one did you get please?
I think he has the 31MM High Output Bulb which gives up to 230Lumens.

I personally got the Long Life Bulb which produces 120Lumens and it is bright and definitely better than stock. (Also 2$ cheaper and 2 years warranty)
 

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Pictures to show thebmentioned SMD Less below.

Like you Amal, I utilized a dummy festoon with LumenHID 5050 SMD 8 LED replacement. the 8 LED board fits perfectly in the translucent cover with the dummy festoon sitting on top of it in the connector built into the cover. I've found the brightness has increased to the point that it lights it up approximately 4 times brighter (Visual approximation). Though if you have large stuff in the back, the right side of the trunk will have shadows thrown on it. I considered LED strips, but once again the draw limitation.
I'm considering drawing up a plan to have the dummy light switch in the cover act as a current source for a MOSFET with a 6 V gate signal that will then draw power from a separate fuse. This way the trunk hatch open/close will still allow the LED strips to turn on and off, and also isolate the lighting current draw from the RBCM. 12V from RBCM through a voltage divider down to 6V.
 

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Discussion Starter #17
wtf

So after being lazy I finally installed everything ( dummy festoon to my bunch of LEDs) and it looks pretty good! (see pictures minus the mess before I put everything back together).
Now I'm having a lovely issue, where even when the hatch is closed the lights stay on. The only way to kill them is by using the little switch in the hatch. I've had 2 electrical engineers check out my setup and they are also stumped.

My theory is the rear light controller isn't sensing enough current or resistance to apply the kill signal to the lights. Which wouldn't bother me except this will drain my batter if I don't drive for a few days. anyone else experience this issue or know of a way to tell the controller to piss off?
 

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Discussion Starter #19
I hope the internal transistor of the RBCM, associated with providing the ground to the hatch light circuit hasn't shorted out, which is what that failure you mentioned as would show up as.
hmmmm interesting. I'll grab a regular bulb today and see if the lights stay on. If they do I'll have to figure some way to test and hopefully replace that transistor. Or worst case replace the RBCM, unless of course the RBCM will just blow again.
also is that from the service manual? I just grabbed v1.3 for the gen 3.
 

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hmmmm interesting. I'll grab a regular bulb today and see if the lights stay on. If they do I'll have to figure some way to test and hopefully replace that transistor. Or worst case replace the RBCM, unless of course the RBCM will just blow again.
also is that from the service manual? I just grabbed v1.3 for the gen 3.
I blew my RBCM when I changed out to an LED bulb. Too nervous to try to replace it again. I just use some battery powered motion sensor light bars to light up the area.
 
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