Eismann

Why do most of the answers for an interior electrical problem always end up with some one suggesting that it is the SJB and a water leak?

For instance, I was having trouble with my trunk/door ajar light coming on. After looking at several threads a common answer was that it must be the SJB. However I had checked that far before reading the threads so I knew it wasn't the problem. Instead, I just changed the trunk switch and there have been no problems since.

I was reading another thread that has a problem with traction control and ABS lights staying on. First answer was SJB, with no other reasoning. Both mine have been on since 2007 after the car was wrecked and the SJB and ABS components were all replaced several times with no results.

Might it be that we, as a community, over use "SJB malfunction?"

Sorry if this is in the wrong location. Just thought I would put in my 2 cents.

danzcool

Because the SJB & waterleak are a documented issue on the 05-09 models. The SJB controls a lot of the electrical issues that are not powertrain related. the issue has to do with some paper gaskets/washers that deteriorate over time and allow water into the passenger footwell just above the SJB. It is almost guaranteed that every 05-09 car will develop this leak at some point because of the paper gaskets. It's highly recommended to do the TSB (TSB #08-26-7) for the waterleak even if you don't have it yet.

Here's the best thread I've seen on the water leak and fix:
https://mustangforums.com/forum/2005...al-answer.html

It's no joke and it has affected more people than having an actual device or wiring failure.

Nuke

+1 on the SJB being a COMMONLY known culprit for electrical "glitches". Whenever I read a thread title about an electrical problem, that's where my mind immediately goes. If an OP does not provide sufficient information to help assume that it might not be the SJB, then the water leak issue is what WILL come up in discussions.

Of course, we COULD leave people to fend for themselves if you prefer...

MustangVixenGT

Yeah they tend to be very leaky was a big problem. I bet my 2013 will leak at some point I am just counting down the days.

Eismann

Yes I know it is a documented issue but I think that many of us jump to the conclusion that it is the only possibility. Don't get me wrong, I have learned a lot on here but I don't think that ALL (if not most) electrical problems derive from SJB. I even recently have had ignition problems and some suggested it was the SJB in one of the first few responses back.

SteveDwsn

I am with you there. I have, for the most part, exorcised the electrical gremlin out of my Pony. The biggest culprit in my case were bad voltage regulators on two different alternators.

Electricity is invisible so it must be magic. I was raised by an electrician and spent some time as a electro-mechanical tech. Most people are intimidated by wiring diagrams, much less schematics. Yes, the water leak and SJB are a problem, but in many cases, a scapegoat.

tx_zstang

Most of the time, people post up of problems after a recent heavy rain. That naturally suggests the most likely and most common cause, hence the wet sjb, especially when multiple systems are affected.
The other reason is probably most people are not able to otherwise diagnose the real issue, whether it is due to the sjb or is something else.
For those of us who can diagnose issues, if it eventually leads to the sjb, well then that's where a problem exists.

Many systems and lights are controlled by the sjb, but that doesn't mean it's always the problem as you've noted.

157dB

I do not always assume it is the SJB,
but it sure is the easiest thing to check first...
If you rule that out then I will
take you down the other harder paths to
finding the problem.
Lets rule out the SJB first.

Like checking for fuel first when the
engine wont start instead of a
complete engine tear down to
find out that the fuel tank is empty...

Ignition and SJB related, I think not...

Ignition and PCM, yes.

The S197 Electrical Guru...

Nuke

What 157db said; ruling out the SJB can save you a lot of other troubleshooting and parts replacement (a.k.a. save you $$). Nobody ever implied the SJB is the only reason, just a place to start given the history of the S197.

teetertotter

You probably read my recent thread on Traction Control and light staying. I updated it today. Both systems came back on and been on for 2 days now. The under carriage of my car has been full of salt, frozen slush and freezing rain. Perhaps the censoring device[s] are no longer covered with winter slush and what not. I will get it to the car wash pretty soon for the usual underbody wash. Temps are still in the single digits this morning.

I will wait for car the wash when in the 20's. It might be an intermittent SBJ, but not jumping to conclusions right now as possibly be an intermittent sensor[s] or just needed to be cleaned off. Perhaps a connection got iced up and fell off due to driving vibrations. We will see over a couple more weeks. We have had nothing but intermittent snow, ice and slush with freezing conditions the past 2 weeks.