Strange noise and gremlin in dash

[ekrampitzjr]

Hi, new member, posted an introduction in the intro forum. Have a question about a weird thing.

2011 XLT Supercab 4-door, 4.0 V-6, 2WD

An electrical noise appears with the truck running or off. It sounds like a fan grinding or a worn-out buzzer. It's coming from around the instrument panel. It does not seem to be the well known blend door actuator problem, which is behind the glove box.

It showed up for me just after a tire shop followed the directions to reset and turn off the tire pressure warning light after replacing two sensors (both rear wheels, the fronts had been done before I got the truck).

I discovered that the turn signal switch or hazard flasher switch would stop the noise, even without the key in the ignition. Playing with the key in the ignition sometimes stops the noise. Hitting the turn signal switch as if making a turn is what I mean. Doing this when the ignition is off also shuts down the anti-theft flasing light in the display. The anti-theft light does not start flashing again even if the switch is turned back off.

The noise is sporadic. It goes away and then a few days later reappears.

All gauges, other warning lights, switches, A/C + heat, turn signals, power windows and locks, remote key fobs, and audio system all seem to work properly.

When I get the truck back from Line-X, I will check the cab ground connection, which I understand is under a panel beside the emergency brake. That was true for slightly older Rangers; still true for 2011? The truck is in excellent shape, but you never know about corrosion.

Any thoughts about the cause of this? Thanks!

 

[ekrampitzjr]

Anyone think the turn signal relay could be the culprit? The turn signals still work, but the relay seems to be a common failure item.

 

[Curious Hound]

First, you may find another cab ground connection over on the passenger side, behind the kick panel. But I am not an expert on that new of a truck.

It sounds to me like your noise may be associated with the battery saver relay or something else on the GEM (may be called the BCM on a truck this new). It sounds like a relay is chattering, which means it is having trouble energizing completely. This could be due to a bad electrical connection or old age.

I'll call this to someone else's attention. @RonD may have a better idea.

 

[Dirtman]

First, you may find another cab ground connection over on the passenger side, behind the kick panel. But I am not an expert on that new of a truck.

It sounds to me like your noise may be associated with the battery saver relay or something else on the GEM (may be called the BCM on a truck this new). It sounds like a relay is chattering, which means it is having trouble energizing completely. This could be due to a bad electrical connection or old age.

I'll call this to someone else's attention. @RonD may have a better idea.

There is no GEM, BCM, or battery saver relay on a 2011. A 2011 has SJB (Smart junction box) and the battery saver system is integrated into it and has no separate relay, its completely computer controlled. The system can wake up or get stuck if there is anything creating a random current draw though. It is capable of detecting current fluctuations in the milliamp range so something like a small short in the radios clock or interior lighting can screw with it.

The cab ground is in the engine compartment attached to the firewall and behind the SJB on the passengers kick panel. Bad ground will also screw up the SJB and cause goofy things to happen. The dumb things are extremely sensitive to voltage changes.

 

[Curious Hound]

I forgot about the SJB term for the device.

 

[RonD]

Yes, 2004-2011 Ranger had the SJB(smart junction box) located in passenger side kick panel, cab fuse box is part of the SJB.
The SJB has most of the cab relays inside, and noise is not coming from there

About the only "relay" left on drivers side is the Flasher unit, so yes, I would swap that out and see if the noise goes away
The Flasher is a combo unit, does Turn signals, but also 4-way Hazard, and 4-ways have 12volts all the time not a "key on" circuit like turn signals, so if failing it could make a noise at anytime, key on or off wouldn't matter

 

[ekrampitzjr]

Thanks to everyone for the help. I discovered myself that the BCM became the SJB after a certain point in Ranger production, several years before 2011.

I'll try the flasher relay first, since it's in the right area to explain the noise and it seems to be prone to go bad on Fords that use it. The SJB is over by the passenger door, and that's not where the noise is.

Just in case, I've found the part number (8L5Z-15604-C) and some sources for the SJB, but I hope it doesn't come to that. Officially, Ford appears to have discontinued it, but some Ford–related parts sites claim to still have it for sale. I've also found the procedure for reprogramming the key fobs if it must be replaced.

Thanks for the tip on the ground location, will keep that in mind.

 

[ekrampitzjr]

Changed the relay after starting a thread to get guidance about removing the dash trim under the steering column. All is quiet now. As I started to remove the old relay, it started buzzing until it was disconnected, so that was the problem as you suspected.

The first replacement, NAPA Echlin, was defective. The four-way emergency flashers would simply stay lit and not flash. Returned it and got a NAPA–branded heavy-duty relay (not Echlin). No problems after that. The first relay might be the first defective NAPA part I've ever had. Be aware this can happen. The NAPA counter guy said defective new relays are more common than you'd think, so exchanging it was no issue.

 

[Curious Hound]

Thanks for posting your fix.