I have a 2010 F150XLT 5.4 with uncommanded flashers intermittently coming on. As of late, the right flashers come on in either the proper position (up) or in the neutral position (off/middle), and the only way to get them off is to turn the multifunction switch to the left (down position). So obviously, I can’t turn my left flashers in at all.

At first I thought it was the multifunction switch, but after replacing that it does the same thing; intermittent, uncommanded flashing. I’ve checked fuses, bulbs and battery and all are fine. In fact, when I unplugged the multifunction switch, the right flashers remained on.

After lots of research, I’ve learned my 2010 model does not have a flasher relay. Seems it’s incorporated with the Smart Junction Box, which is integrated with the internal fuse box on the passenger side kick panel. It sounds like I need to replace this smart junction box. 1) Is this correct? Is it an SJB issue?
2) If so, it doesn’t look difficult for a wanna be weekend mechanic to replace. Has anyone replaced an SJB?
3) Does anything need to be reprogrammed once the SJB is replaced? It simply looks like 6-8 wire connectors that look to be just plug and play. If software/programming is required, this would be my only issue. I don’t have the software nor the knowledge to use it.
4) Would I even be able to start and safely drive it if I replaced the SJB and had to take it somewhere to be programmed?

Ford quoted me over $1300 to fix it. A new SJB is $400 and labor is $800 (plus tax). I just haven’t seen anything that would even come close to requiring $800 in labor! And I can get used SJB’s for around $150. Is $1300 justified?

Thank you all in advance for any advice you can provide!

 

Did you check the electrical integrity of the wiring between the MFS and the SJB before condemning the SJB?

Have you scanned the SJB for any fault codes?

Most needed scanning and programming tasks can be done in Forscan on a Windows laptop with the recommended OBDII adapters.

 

I have had a scan performed at a local parts store, but I’m learning they and/or the scanners they use might not be able to see the actual results. I also don’t have FORScan. A quick Google search seems to indicate it’s a free downloadable software. Can you please confirm? Is it difficult to figure out how to use?

I have not confirmed the integrity of the wiring either. Would that be a simple multimeter task, testing each wire at the MFS connector to the SJB? Might be a silly question, but is one of the connectors going into the SJB the other end of the connector going into the MFS, or is it only a part of a larger wire bundle/connector on the SJB side?

Thanks again!

 

Quite likely.
Yes it's free and there is a learning curve. You do need to but the OBDII adapter, around $35 for their recommended one.
Yes. Also checking for shorts to power, ground or adjacent wires.
Much larger (52-pin connector).