posted 10-17-2007 11:47 AM                  

quote:

---

Originally posted by GRROWL:
[QUOTE]Originally posted by kat hunter:
[B] I think in my case I have a mechanical problem. My light is almost always on except if I take the car over a certain speed the light will always go out. Makes me think the mechanical switch is corroded.

---

Based on my understanding of the sensors, the mechanical components are:

1. Pressure transducer
2. Valve core
3. Centrifugal switch
4. Magnetic switch (which, hopefully, is combined with #3)

1. The pressure transducer can sometimes be "kicked" into working by overfilling the tires, running them for a while and then letting out the extra air. That doesn't seem to be involved here.
2. The valve core can corrode, especially if it was replaced with a steel core (thanks to MDProwler's correspondence with the manufacturer). The stem acts as the antenna for the wheel sensor transmitter. Suggest the following: with air in the tire, unscrew the valve core and scrub the inside of the stem with a very small brush or a pipe cleaner. If there's any corrosion, replace the core with a non-magnetic plated core (you can determine this with a magnet at the store). Work quickly so that the air blows out any particles rather than letting them clog the sensor. Use a plastic cap on the sensor just to make sure (per Chrysler's recommendation, but I don't really think this will matter).
3. A centrifugal switch is used in each sensor to preserve the battery (at least 10-year lithium ion) - the wheel has to be turning approximately 20 MPH (if memory serves) to close the switch. There's not much much you can do about this UNLESS it's combined with the magnetic switch, so . . . .
4. Magnetic switch - a magnet is placed around the stem to activate the sensor to send a signal while the car is standing still. This is either a separate switch (such as a reed switch, used only for program mode) OR it throws the centrifugal switch. If the latter, cycling the centrifugal switch a few times with a strong magnet may just "kick it" back into operation. If you can't find a strong donut magnet, I suggest that you find a junk microwave oven and extract the two STRONG donut magnets from the magnetron. If you place one over the stem and remove it quickly a half-dozen times or so, you may just "kick it" back into operation.

Just a shot. Maybe crazy enough to work (actually, no crazier than the overinflation route that has worked at times).

Give it a shot and let us know.

posted 10-17-2007 04:15 PM                  

1. Confirm tire pressure is OK.
2. Disconnect battery for an hour and then reattach.

I cleared an engine trouble-code that way 2 weeks ago, which apparently FIXED the problem.

posted 10-17-2007 05:57 PM                  

quote:

---

Originally posted by Gary C:
I dont think you need to wait an hour, if you take off the positive cable and touch it to a ground it will reset. I did this on the Old Hiboy when i had problems with it.

---

"The Book" says 20 minutes. I do it for an hour to be safe.