Hey,

So i had been dealing with the dreaded water leak onto the passenger floor of my 2007 Mustang GT for a while. I'm pretty sure i buttoned everything up there (sealed the 10 grommets under the cowl, replaced door weatherstrip and window trim weatherstrip) and don't actively feel like water is coming in anymore. This was a few weeks to a month ago that I did this. I had no electrical issues at this point.

Fast forward about a week ago and I swap in fuel injectors from a 2016 mustang GT and load a tune from Lito for the first time and about 30 miles later all hell breaks loose. Started with ABS and traction control lights being on, then CHECK BRAKE SYSTEM warnings, now I have CHECK CHARGING SYSTEM, a CEL, and Fuel Level Low (it's not) and also DTE ODO DATA ERR. Additionally, the tachometer is jumping from 800 RPM to 0 RPM in a slow and steady pattern. From my Bluetooth OBD scanner I pulled codes U0073, U1900 and U2011. I brought up my concerns to Lito and he said there isn't any way the tune is causing these issues and to check a large white connector by the SJB.


I disconnected the battery, checked the large white connector and I have looked at all of the SJB connections and found that some of the connections looked MILDLY corroded and I cleaned them and they look okay now. I also replaced a few fuses in the SJB that looked iffy and I have checked the fuse box under the hood and all looks okay. I even read that possibly the "diode" in slot 53 under the hood could be a cause of some of these issues so I swapped it with the other diode that's in there and it did not help.

Is the SJB just shot? Is there something else I should check?
If I bring it to a shop is an automotive electrical shop a better bet than a regular auto shop?

Just really stressed and despise electrical issues (had a '97 Golf GTI years ago that water would leak onto fuse box under dash, all sorts of annoying stuff happened there), any help would be appreciated. Thank you.

Edit: felt I should mention only other mod's on the car is a JLT CAI. Before the Lito tune was just a BAMA tune.

 

Sorry to bump so soon but there's been some development.

I decided to swap back to stock injectors and load the BAMA tune I had on before. I haven't driven it but did start and idle and ABS/Traction control lights are still on but tach is no longer jumping and no longer getting CHECK CHARGING SYSTEM and CEL is off. Interestingly when i plugged in my bluetooth OBD scanner the CHECK CHARGING SYSTEM immediately came back and the RPMS started going from 800 to 0 again with a CEL. Unplugged it and those symptoms stopped. Codes when scanner was plugged in remained the same.

I am getting a TMPS error but I think it's possible that when I cleaned the connections on the SJB they were reset when I unplugged the battery? I will pair them tomorrow (I have the tool).

 

Pull your cabin air filter (under the hood, passenger side up near the cowl) and make sure the drain holes in the bottom of that space are NOT clogged or stopped up. This is the #1 reported reason for electrical issues, and the #1 reported way the SJB gets wet.

 

Thanks for the tip, those are clear though. I had cleared them and removed the rubber bits a while ago.

Edit: Driving the car to work today ABS and traction control lights still on and it's saying CHECK BRAKE SYSTEM still but none of the other issues. Plugging in the Bluetooth OBD scanner doesn't cause the issue reported above as of today. Will update if ABS lights turn off over time with driving once it has some more miles on it to do all of the checks. Only 1 U code left in the system (forgot which one and at work ATM)

 

Have you opened up the SJB to see if there is any corrosion that you may have missed?
Happened to me before I waterprooded my car. I had to clean and replace a pin in the SBJ cause I was getting so many electrical issues.