RECALL:brake switch/speed control

[wpurple]

The recall years back involving fires with Ford vehicles never included a Explorer or Mountaineer even though the Explorer's and Mountaineers use the same exact switch. (The cruise control deactivation switch mounted on the master cylinder)
Now the recall does involve the model year 98 for Explorer's so it indicates to me that someone either died or was seriously injured in a Explorer finally.

Since my 97 Explorer and 99 Mountaineer use this SAME switch, I decided to change the switch to the new one. (Both vehicles are in my garage, and I wouldn't want to lose my house, myself, or my family)

New switch was $18.98, took all of 2 minutes to change.

Dealer said to save the receipt, as soon as your model year is included, come back and we will refund your $$$$

At least my spark plug hasn't blown out of my F250 yet.... :fire:

 

[Rick]

From the sound of the recall they didn't end up replacing the switch they ended up putting a fused harness leading to the switch so if the switch did fail the fuse would blow.

 

[Rick]

From the article: "Owners of the newly recalled vehicles will receive notices in the mail in a week and dealers will install a fused wiring harness".

 

[wpurple]

Rick,
Yes, you are correct, but the switch was cheaper than the fused harness, and the dealer recommended just changing the switch as there is no way to accuratly determining the condition of the original switch.

 

[budwich]

something happen to the system during input and this ended up on the wrong post....hmmmm????

 

[wpurple]

From what the dealer said, the brake fluid will pass thru the mylar film that seperated the electrical contact from the fluid, causing the feed voltage to short to ground, in turn causing the wiring harness to fry.

Evidently brake fluid has a low resistance

 

[BrooklynBay]

Check this thread: http://www.explorerforum.com/forums/showthread.php?t=163985, and this one: http://www.explorerforum.com/forums/showthread.php?t=163990

 

[shaker1]

Just checked mine and it is red. Going to dealer next Friday. Will replace the switch if they don't. Dealer only item?

 

[scucci]

The NHTSA has a pdf with the whole story on the switch problem.
The switch has a DuPont Kapton Diaphragm coated with Teflon. The kapton is degraded by moisture, the Teflon is there to protect it from any moisture from the brake fluid which is very hygroscopic. The Teflon fatigues, allowing moisture laden brake fluid to degrade the kapton. This allows fluid to get inside the switch chamber. If the switch is mounted vertically up electrolysis causes conductive dendrites to form between the power contact and the grounded shell of the switch. As more dendrites form more current is fed through eventually causing the switch to melt and possibly cause a fire. In order to have this happen there are certain required conditions:
1: Switch powered at all times.
2: Vertical up or near vertical switch mounting (not pointing down).
3: Greater than 5 PSI (10" HG) Vacuum pulses at the switch.

All recalled vehicles have the three conditions above. Except the 1998 explorer. It is not known what mechanism is causing the 98 expy to have the switch failures, since vacuum pulses measured in it's system were below the 5psi value. That is why it was included in this newest recall.

Vacuum pulses occur when the brake pedal is released and fluid can not fill the void fast enough. The F-150 has very high pulses. Rangers have low pulses. The design of the switch is spec'd for 500,000 actuation's lifetime minimum. But the designers never took into account the reversing of the diaphragm from the vacuum pulsing, causing doubling of the actual pulses and fatiguing the Teflon.

Hope this sheds some light,
Scucci

 

[gijoecam]

Dendrites.... are those like Tribbles? Oh, wait, no... didn't they use Dendrites to kill Vicki in 'I, Robot'? Oh, duh, those were Nannites... didn't they use dendrites to fend off the Borg in..... wait.... What was the question?

-Joe

 

[gijoecam]

Just did a quick skim of the NHTSA PDF file. I'll do some digesting over the weekend, but the info looks pretty neat.

Also, if you're thumbing through, if you look at the x-ray pics on page 26, my desk is about 20 feet from the guy that did those

Also, as I (quickly) read it, it's a combination of problems that could not be forseen. Ford installed the sqitch supplied by TI for the application. Nobody ever realized that vacuum could damage the seal. Vacuum events occur both at initial fill and during subsequent braking events. (I never knew the latter) and apparently one or both are sufficient to damage the seal. Pretty amazing to think that the damage may have been done before the trucks ever rolled off the line!

-Joe

 

[kfkodiak]

Final NHTSA report on the issue:

http://199.79.180.162/prepos/files/Artemis/Public/Pursuits/2005/EA/INCR-EA05005-24323.PDF

 

[huntersteve61]

Has Anyone Every Had A Problem Getting Their Cruise Control To Engage??? Mine Will Only Engage Sometimes And Only After I Tap The Breaks/Do A Speed Up

 

[Stic-o]

At least my spark plug hasn't blown out of my F250 yet.... :fire:

Just make sure to check them everytime you change the oil. Both my dad and my uncle had this happen. $$$$$ Only happens on the 5.4 prior to the 2004 3 valve design.

 

[gijoecam]

Just make sure to check them everytime you change the oil. Both my dad and my uncle had this happen. $$$$$ Only happens on the 5.4 prior to the 2004 3 valve design.

OK, enlighten me please. How exactly do you check the spark plugs at every oil change??? It would require removing the fuel rail and each coil pack, and then what do you do?

-Joe