Fuse 12 feeds - mostly not working, resets with a fuse pull

[Ozzie]

OK, I'm stumped on this one and would welcome some assistance.

All my Fuse 12 feeds (door, dome, engine bay lights, and everything else on it) are not working ..sort of.
I've pulled Fuse #12, and it is good, and even replaced them, but still the same results.

My fuse 12 feeds are all out right now, so doors open, no door nor dome lights are on.

Since this started, I was able to get fuse 12 feeds working when I did this:
If I pull out, and replace back, Fuse #12, then I get all functions back. Once the door closes, and is opened again, all functions are out again. Fuse 12 is never blown, when I pull it out. This is repeatable.

I was mucking under the driver's dash last month, playing with the door buzzer (replaced it with a GM chimer) and while that is on a different fuse, perhaps I pulled or jiggled something out by mistake in this area. ??
Diodes? I saw some thing on another post about blowing diodes; I saw there are some diodes on fuse 12 circuits, would this have anything to do with it, and if so, where are all these diodes?

Any diagnostics or theories welcome.
Thanks.

[Ron]

Sounds like the fuse's connectors are pushing back, weak, or loose and the load causes the connection to break.
Try a jumper, temporarily.
Look for a junction getting hot/corroded/etc

[Bitsyncmaster]

Sounds like you need one or more of those resistors I send with my dome light unit "over" an LED so my dome light unit will see enough load to turn on. Different types of LEDs have different voltage drops. If your LEDs have strings of 3 or 4 LED chips the voltage drop may be to high so the resistor lowers that drop. On my car I have one resistor on the front dome light. Note I still have an incandescent in the glove box or I would also use a resistor over the glove box light. You may also need one on the hood and engine light if you want the unit to power up when you open only that light.

[Ozzie]

Sounds like the fuse's connectors are pushing back, weak, or loose and the load causes the connection to break.
Try a jumper, temporarily.
Look for a junction getting hot/corroded/etc

Sounds like a good suspect, even though I re-did the fuse box (new, with new clips) a couple of years ago. I'll try it with a jumper.



Sounds like you need one or more of those resistors I send with my dome light unit "over" an LED so my dome light unit will see enough load to turn on. Different types of LEDs have different voltage drops. If your LEDs have strings of 3 or 4 LED chips the voltage drop may be to high so the resistor lowers that drop. On my car I have one resistor on the front dome light. Note I still have an incandescent in the glove box or I would also use a resistor over the glove box light. You may also need one on the hood and engine light if you want the unit to power up when you open only that light.

But the thing is, it was all working perfectly fine up to two months ago, and I was running all LEDs, the same LEDs that are on now (....well, the only exception was the glove box LED, but I only changed that. the type, this week), and with your dome light unit. . I had read an earlier post from you that you saw the need for the resistors with newer LEDs that had tiny caps? resistors? on them, again these are are mostly two year old LEDs on this circuit. Still, am willing to try the resistor method. Is there a picture reference? What resistance value?

[Bitsyncmaster]

You can always do a quick test if the resistor will work by installing an incandescent bulb in the dome light.

You can not use any LED that has a capacitor on the courtesy light circuit.

[Ozzie]

You can not use any LED that has a capacitor on the courtesy light circuit.
Check. None of my LEDs have that.


You can always do a quick test if the resistor will work by installing an incandescent bulb in the dome light.
Good tip, I'll try that as well today.

[Ron]

LEDs ??? :biggrin:

[DMC5180]

Ozzie,

The Glitch is in the DDLM. (Sensitivity to LED's) This happens to me on a semi-frequent basis. Sometimes pulling fuse 12 and reinstalling it will reset the unit. Once in a while I have too disconnect the battery to restore the operation (I have a quick disconnect installed for extended period non-operation anyway). For me, it seems to be more of an issue IF I have the doors open and Hood open for extended periods. That said, my trunk LED does have CAP on it. It could be a contributing factor. I've also replaced the door LED's recently with a 5 SMD version. I can't tell if they CAPS or not.

[Ozzie]

Ozzie,

The Glitch is in the DDLM. (Sensitivity to LED's) This happens to me on a semi-frequent basis. Sometimes pulling fuse 12 and reinstalling it will reset the unit. Once in a while I have too disconnect the battery to restore the operation (I have a quick disconnect installed for extended period non-operation anyway). For me, it seems to be more of an issue IF I have the doors open and Hood open for extended periods. That said, my trunk LED does have CAP on it. It could be a contributing factor. I've also replaced the door LED's recently with a 5 SMD version. I can't tell if they CAPS or not.

Thanks Dennis.

In my case, it's odd that this anomaly would start now, after working fine for nearly two years (and no recent bulb changes).


Update:
1. I just replaced the LED bulb on the front dome light, with an incandescent bulb. Same results, it resets with the fuse pull.
2. Just started to pull the fuse box up (hoping that doesn't create further issues), to check the wiring into the pins for the #12 location.

[Ozzie]

Update.

Well I pulled the fuse box out, just enough to tug on #12's wires, and yup, the ground wire just came out of the terminal.
I re-soldered the wire to the terminal, and put the fuse box back. As soon as the fuse went in, all lights on. Push the door switch and.... no lights.
:huh:

Maybe this is a combination of everything you guys have said, LEDs and a bad connection on fuse.


Now that I've got a solid connection at the fuse, I am going to try a couple of other things:

1. The only new LED on the circuit is the glove box LED, that I posted/tested/verified on a different thread. I'll disconnect that out to see if that affects the results any.

2. Original dome relay. Doesn't make sense the new digital one would all of a sudden cause this, but I noticed that if I flick the door switch off and on, all the fuse 12 circuits go out as they should, and come back on. So this now only appears to happen when the fuse 12 features dim down, that they don't come back on until a fuse pull/reset.

[Ozzie]

OK, I results to my previous update:

1. I pulled out one the connectors to the glove box, to take that light out of the equation: Same results.

2. I replaced the digital dome relay, with the OEM (white) relay. No fuse 12 circuits operate, even with a fuse reset, and a battery reset (I have a quick disconnect on the battery). So I plugged back the digital one, and confirmed the behavior remains (needs a fuse reset).


What I did notice was that:
a) I can get normal operation even if I push the door switch and knock out the door and glove box lights, for a few seconds, as long as it is before dome lights dim out.
b) If I immediately replace the fuse as a reset, it doesn't work. A fuse reset only works as long as I wait 15-20 second to put it back in.
c) My rear dome light is dimming at different rate than the front dome light - I'll check that next, in the afternoon. Family duty calls now.


Any further ideas with the circuit behaviors observed, appreciated. Thanks.

[Bitsyncmaster]

It has to be the ground pin on the dome unit plug is not a zero ohm to ground. This is happening so much lately too many cars. Someone just found the same on the fan fail plug. What happens is the first relay (far right side) has a wire going to the ground junction then the rest of the front relays are daisy chained off that first relay. So any bad ground (crimp is poor) results in the all the relay to the left of that one bad. My fan relay had a bad ground in my car. So I ended up crimping a new pin with one wire for each relay socket and joining all those wires to one common ground wire.

The latest dome units shut down if the power (+12 to ground) is insufficient.

[Ozzie]

SOLVED!
:biggrin:

Before tearing into the relays to check grounds, I checked this:
"c) My rear dome light is dimming at different rate than the front dome light - I'll check that next, in the afternoon."

Well waddaya know:
http://dmctalk.org/attachment.php?attachmentid=20624&d=1374439596
Found this bad boy in my rear dome light. The front dome LED looks just like this, but doesn't have the capacitor (black module behind the SMD LEDs). As I wrote before lunch I noticed it's behavior was different when it dimmed, than the front's. I rarely use this dome light, because I have an older Flux Capacitor unit back there, which I'm too lazy to remove - so it's sort of permanently there now. Perhaps about a few months ago, I said, "Hmmm, it'd be kinda cool to have the backlight of the Dome Light on. And it did work fine, but I guess the wire clip's wire bad contact finally gave recently, and the combination of the two must have made it all go haywire.

Anyway, I removed that LED, and reset my fuse, all door and dome lights came up as has been happening. The real test is would they continue to reset after the dome light dimmed. Nope. ALL Fuse 12 circuits came back up, at once (curiously, and it makes sense, the glove box LED as power even with doors closed), no fuse reset needed. Verified it twice, and the dimming feature of the digital dome unit continues to wok great.

So, yup, you were ALL right (wow, like a mystery where everyone is guilty!).
- I had a bad connection at the fuse clip (Ron)
- This was an LED issue (Dennis)
- It was specifically an issue of an LED with caps on it (Dave)

Woohoo. Got my LED door lights back on ....which I must say being the DeLorean serial LED blogger, was kind of embarrassing to not have them on. :umm:

Thanks for everyone's input.
Documented in case this someday may assist someone else.

[Bitsyncmaster]

I may someday redesign the dome dimmer unit so you could use those switching regulator LEDs in locations other than the dome lights. But they will never dim with PWM unless the design of the switching regulator circuit in the LED is changed.

That capacitor supplies power to the LED for short durations when the power is turned off (PWM). So no dimming of the LED happens until my PWM has almost shut the power down compleatly. Hence you would see a very short dimming cycle.

That same process is why I can't dectect a LED is on. I switch the power off at a very short cycle that the eye can not see to measure current (an LED still on).

[DMC5180]

It has to be the ground pin on the dome unit plug is not a zero ohm to ground. This is happening so much lately too many cars. Someone just found the same on the fan fail plug. What happens is the first relay (far right side) has a wire going to the ground junction then the rest of the front relays are daisy chained off that first relay. So any bad ground (crimp is poor) results in the all the relay to the left of that one bad. My fan relay had a bad ground in my car. So I ended up crimping a new pin with one wire for each relay socket and joining all those wires to one common ground wire.

The latest dome units shut down if the power (+12 to ground) is insufficient.

This is the first I've seen this explanation. It is certainly plausible this is where my issue lies. But I don't get that last sentence. Please define insufficient?

[Bitsyncmaster]

This is the first I've seen this explanation. It is certainly plausible this is where my issue lies. But I don't get that last sentence. Please define insufficient?

Insufficient would be about 6 volts. I don't think you have the later version I started adding this to. I did this to prevent burning out the units when you had a bad ground wire.