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Went to unlock my car yesterday to find that it would not unlock. Figured the key fob was dead, no biggie. Then i noticed that none of the dome, map, or courtesy lights would come on unless all the doors are closed, and they are very very dim. The trunk light is also out. The trunk open indicator stays dimly lit at all times when the car is on, and gets brighter if i open the trunk or doors.. The power door locks, headlights, trunk and gas poppers only work when the car is on.
Ive inspected and replaced all fuses and relays, both under the hood and dash- changed nothing.
The only thing ive been able to find from searching is that it could be the SECU..
I don't have a definite answer on this, but it is possible. The SECU has timer circuits to turn off the interior lights if you leave the doors open, leave the headlights on, open the door locks and stuff, so it does control those items.
It has 2 sources of power, one that comes through the ignition switch when the switch is on and another one that is live all the time. It sounds like the the power input that is live all the time is missing. Without having a CONSULT tester, I don't know how you would go about testing the SECU.
All you can do is gamble and get one from a junk yard and see what happens. You have to get a SECU from a 2001, the 2000 and 2002/3 are all different.
I don't have a definite answer on this, but it is possible. The SECU has timer circuits to turn off the interior lights if you leave the doors open, leave the headlights on, open the door locks and stuff, so it does control those items.
It has 2 sources of power, one that comes through the ignition switch when the switch is on and another one that is live all the time. It sounds like the the power input that is live all the time is missing. Without having a CONSULT tester, I don't know how you would go about testing the SECU.
All you can do is gamble and get one from a junk yard and see what happens. You have to get a SECU from a 2001, the 2000 and 2002/3 are all different.
I figured itd be something along those lines.. i went to a junkyard yesterday and not a single one..out of 8.. had the correct secu for me to even try. Just my luck. Went and looked over all my add on electrical stuff and theres no compromised wiring.. the key fobs work with the fob on as well, so i think youre right.
It has been a rough past month, and I just now got around to playing with the SECU.. i just opened it up and found that it appears the board is missing a piece.. Can anyone confirm this? Is there anyway to test it?
Is there anyway to repair this without that piece ? I have been unable to locate a SECU with the correct part number and refuse to pay $600+ to go through the stealership.
I doubt that anything is missing. That looks like the mounting pad for another transistor like the black thing to the left of the silver square. It is fairly common for a printed circuit board to have empty spaces for a component, pcb having been designed for options/features that are not being used/implemented.
I can look at my 2000 tomorrow when I get it back, but I am not sure what I might see being for a different year.
I do believe that the 2000s have tan 2 harness SECU's.. whereas mine has a 3 harness white SECU. not 100% sure.. It isnt noticeable in the picture but it seems as though theres residue on the pad, which is what made me wonder if something was there.
Truly frustrating issue, especially since I cannot locate another one with the same part number. Ive looked at over 15 junked maximas and had no luck finding the same one
I do not one to blow a ton of money on one if it does not fix it.
Looking at the FSM EL-89 the trunk light isn't controlled by the SECU but always gets power and is enabled by a switch to ground.
Can you confirm the voltage at the trunk light?
There are some reference values for the secu around EL-94 and later. You can verify the inputs wires to the secu match the reference voltage and that can help confirm or deny the secu being good/bad.
Have you inspected the solder joints on the secu? Specifically the solder joints for the relays (black boxes)?
Looking at the FSM EL-89 the trunk light isn't controlled by the SECU but always gets power and is enabled by a switch to ground.
Can you confirm the voltage at the trunk light?
There are some reference values for the secu around EL-94 and later. You can verify the inputs wires to the secu match the reference voltage and that can help confirm or deny the secu being good/bad.
Have you inspected the solder joints on the secu? Specifically the solder joints for the relays (black boxes)?
On the contrary, that 12v source does come from the SECU, pin 49 i do believe.. check the top of 89 (right below "spot")
I wont be home until the weekend, hence the reason i havent used a DVOM with that chart yet, I appreciate the help!
So, I had some wire laying around and decided to do what I could to test everything out. First, i ran a wire to all the ground pins on the SECU harness-- grounded them to the front seat bolts, nothing.
Then i took the shifter trim off and plugged a wire into the positive terminal of the cigarette lighter. I put the key in the accessory position (enabling power to the cig lighter), and placed the other end into terminal 49.. car lit up like a christmas tree. Thus, @DennisMik was spot on in post #3.
Now the fun part will be figuring out where the issue is, i did find this handy chart though, hopefully it will be one of those things.
Ill report what I find over the weekend, hopefully I will have some success.
You know...all sorts of funny electrical gremlins can be caused by poor grounding or an alternator on its way out.
You may want to check your grounds to ensure they are completely solid and corrosion free. Your alternator can be tested with a voltmeter. The FSM has specific values to look for when testing with a multimeter.
On the contrary, that 12v source does come from the SECU, pin 49 i do believe.. check the top of 89 (right below "spot")
I wont be home until the weekend, hence the reason i havent used a DVOM with that chart yet, I appreciate the help!
Actually pin 49 and the trunk light are fed by the same wire coming from a fuse in the battery (there is a circle which denotes connection where the line from the battery, to the trunk light, and to pin 49 of the SECU meet). It's at the bottom of page 89 in the schematic diagram.
Actually pin 49 and the trunk light are fed by the same wire coming from a fuse in the battery (there is a circle which denotes connection where the line from the battery, to the trunk light, and to pin 49 of the SECU meet). It's at the bottom of page 89 in the schematic diagram.
DennisMik was on the ball as always
i missed that intersection my apologies. The bulb was simply burned out-_-
So after inspecting all of those things above, the problem had not been solved. I swapped fuses and relays around again to no avail. I jumpered the 12v from the cig lighter one more time to the SECU and when I took it off everything stayed on! I have no idea how that even makes sense but for now I am not complaining. Everything is working 100% again, for now at least. Not sure if anyone can explain this ?
Maybe the the pin that connects the power to the SECU had some corrosion and now after all the wiggling and moving, it has been cleaned up. All we can do is hope.
But on the "controversy about the trunk light, I have to side with AaronL. You have to get used to how Nissan drew the wiring diagrams.
Fuse # 13 supplies power direct from the battery to the SECU on pin 49. Nissan taps into the wire from fuse # 13 and sends the power to a total of 17 different circuits, the trunk lamp being one of them.
The way Nissan does most of the lamps is to supply 12 volts to them. To make the lamp light up, it grounds the other side of the lamp.
08-13-2015, 09:42 AM
my apologies. The bulb was simply burned out-_-
