Did my Smart Junction Box go bad?

[RIO RED SNAKE]

Hi guys, just bought a 07 GT500 with 35k miles..

The car has no turn signals show up on the dash, oil pressure gauge does not work, no fuel gauge working either, but all lights work like they should..and

It says, Low tire pressure, check engine light, oil press low, parking brake on even though it isnt and a few more dings with warning descriptions. I did a few searches and found what the p0268 and p4xxx something (can't remember) codes were and alot of 05+ owners were having similar issues as well as a few GT500 guys...

What is my next plan of action? If i change the box and get a used one do i have to get my keyless remote reprogrammed as well as key etc?

I tried the battery disconnect trick and it does not work..Boost and Engine temp work perfect. THanks guys!

 

[54First]

Just a guess. Bad battery and/or alternator.

Steve

 

[54First]

There's also a small plug behind the instrument cluster that handles all the communications for the gauges. Maybe it's loose. It's not hard to access.

Also could be a bad ground. Check your negative battery cable.

And of course, fuses.

Steve

 

[RIO RED SNAKE]

Steve, the battery was dead when i received it off the car carrier, but, when i jumped it the dome lights were left on! so i clicked the adjuster down and now it is fine, i put it on a battery tender for a overnight and it starts up like new, alternator is charging..so maybe i do have to change the battery then.?

I was hoping after the full charge and some driving around that i have been doing it would fix itself. I will check the connectors behind the gauge cluster when i get a chance. Thanks for the input. Ill try a battery on monday or something and report any findings, any other input is appreciated. -Christian

 

[RIO RED SNAKE]

Guys, bumping this due to the same issues.

I Did NOT change the battery, charged it for a full day, car starts like day 1 with no issues, so i do not think the battery is the cause.

Oil Pressure Gauge does not work, Fuel Gauge does not work, traction control is off, brake light, tire pressure, check engine, turn signals work but do not light up on dash, no reverse lights, HVAC controls do not work, (used to but a/c did not blow cold), and power windows do not work.

WHAT IS GOING ON!!!? I checked every fuse on the pass side kick panel, under the hood fuse box, they are all GOOD, none are burnt out...

Can someone please point me in the right direction here. Is a new smart box needed? Thanks!

 

[fullboogie]

Did you check the SJB in the kick panel?

 

[54First]

Your Smart Junction Box is a component of all the circuits you mentioned. I'll guess that it's a fairly expensive part. If you buy one and it's not the problem, as an electrical part it's probably not returnable. If it were me, I'd search for a bad chassis ground first. Next I'd unbolt the SJB and verify that all connectors are seated. Next, I'd reluctantly bring it to the dealer where they have the equipment to do a diagnosis. It could turn out to be the least expensive solution.

Steve

Second thought: Does it have or did it have an auxiliary theft alarm? They can cause some of your symptoms.

 

[RIO RED SNAKE]

THanks for the replies guys, i did check all the fuses in the smart junction box. There are 3 or 4 slots where fuses are missing for some reason. So i got the power windows to work again, but everything else is still not working.

I am going to go over the whole car for a bad chassis ground somewhere and hopefully that will shed some light, also going to pull the cluster as well to see if something came loose there. I will unbolt and remove the SJB as you reccomend trying, i refuse to bring it to the dealer for the time being, but i have a local auto electric guy who is on it now, so hoping to shed some light there.

I will check all of that first, and as for cost, the SJB is only 50-150 used (from 05+gt probably different), probably new around 2-300 $ which i agree if i purchase and try i am sure i can not return.

All good options for me to check out. Thanks for the help... I do not think it has a secondary alarm, the factory ford honking one works.

 

[RIO RED SNAKE]

Got the HVAC controls to work, but a/c compressor isnt turning on, so i am sure that will be a fuse or something somewhere. So windows and HVAC fixed, everything else stayed the same..will keep trying and updating.

 

[54First]

I'm curious. What did you do to get the windows and HVAC to work?

Steve

 

[RIO RED SNAKE]

There were 3 spots where the fuses were missing in the Smart Junction Box in the pass side kick panel. I have no idea why the windows and HVAC worked before, but they stopped now, anyways, we put (3) 5amp fuses in those missing slots and the windows and HVAC came back to life, A/C compressor still does not kick on but going to work on that and look for bad grounds today. The car was previously Hit in the rear if that makes a difference if there are some Major grounds located back there or not besides the FPDM's.

 

[RIO RED SNAKE]

UPDATE: Pulled my passenger seat out to find that none of the air bag connectors were plugged into the seat. I dug them out of the carpet and plugged them in. Airbag light is now fixed 100%.

#2) I unplugged, removed, and blew on the Smart Junction Box, my car made all sorts of noises during the process of plugging in and unplugging. I also put a new interstate battery in it and fired it up. No changes to all my warning lights and fuel gauge and oil pressure gauge remedies. So i put the old battery back in and have it hooked up to a slow charge through the night.

Do you think the SJB is bad? I know you guys normally never deal with issues like this, i was also under the car and all grounds in the trunk area and rear of car look fine, i know once i find a bad fuse/ground/connector all my dash remedies will be fixed. No corrosion or signs of water either in the kick panel. Any further input appreciated.

 

[54First]

Have you checked the connector on the back of the instrument cluster yet? Several problems are showing up on the cluster. Put a towel over the steering column cover to prevent scratches. Pull out on the panel with the silver trim rings to remove it. Then remove the four screws that hold the cluster in place. The connector is in back of the upper right corner if I recall. Since several problems have been the result of someone's carelessness/stupidity, I'm not yet ready to say the SJB is bad.

Steve

 

[RIO RED SNAKE]

Ok Steve, thankyou for your input, i will give that a whirl tonight or tomorrow at the latest and report back. That would be wonderful if it was indeed the connector on the back of the cluster. Will use the towel trick as well, have to try and keep this bad boy as nice as possible.

 

[RIO RED SNAKE]

Well, semi expensive diagnostic day. Ford banged me 110 for 30 min of their time. They checled my airbag lights. Then i pulled the box out and opened it up and it looks like someone scratched away at some glue on the circuit board. So i orderes a new SJB it will be in tomorrow for $205 and then will install and havr it programmed and hope that it fixes my problem.

 

[54First]

That's about right for a dealer shop rate.
Hope the new SJB does it. I'm rooting for you.

Steve

 

[RIO RED SNAKE]

Hah, thanks Steve i really hope this is the issue, im rooting for the old girl to pull through, getting a little edgy now.

 

[RIO RED SNAKE]

UPDATE...new SJB put in..did nothing... -__-

so, there is a communication error somewhere with one of the wires going to a module. i would also like to add i have no amplifier or door speakers installed yet, so i am curious if the NO amp being present is causing this communication error since a dataline connection goes into there.

I do not have a factory amp to put in the car at this time to test, so i am going to purchase one and see what happens next i guess.

 

[kody7k]

Bump... having the same issue with my 08GT500, what was the end problem? need help....

 

[Wildman113]

UPDATE...new SJB put in..did nothing... -__-

so, there is a communication error somewhere with one of the wires going to a module. i would also like to add i have no amplifier or door speakers installed yet, so i am curious if the NO amp being present is causing this communication error since a dataline connection goes into there.

I do not have a factory amp to put in the car at this time to test, so i am going to purchase one and see what happens next i guess.

Did they give you the codes?

Communication faults can definitely be difficult to diagnose, but they are typically caused by a damaged circuit or connector. If you can get the codes, I may be able to provide more assistance.

The audio equipment communicates on the MS-CAN bus, while the PCM, Instrument Cluster, RCM (airbag), ABS Module, and others communicate on the HS-CAN bus. Therefore, even if the amp communicates on the network (not suspected) it should still not cause a fault in the Instrument Cluster.