OK, here we go. 2002 Explorer XLT, 4.0L, 2WD. 48,889 miles. The last two days, this is what this truck has been doing. While driving around town, the check gauge light comes on, the fuel gauge goes to empty, and the speedometer goes to zero (no other gauges affected). Immediately following these three things, the A/C goes to hot. Once the vehicle is turned off after this, the PATS kicks in and the vehicle will not start (with either transponder key), with the "Theft" light flashing quickly. Eventually (15-20 minutes) the vehicle can be started and everything may go back to normal, for a mile or so, and then it repeats the process, always ending with only the fuel gauge and speedo zeroed out, check gauge light on, and A/C blowing hot air (A/C clutch will not engage once the gauges do their thing). Do these things even have any commonality to each other, other than electricity?!?!? PLEASE help, it was 110F here today, and I would really like to get this A/C back on. Thanks in advance!

 

If you have a multimeter, monitor the system voltage when this occurs.

If you have a friend with a professional scan tool, have them check the codes in the PATS unit, looking particularly for a code related to KAM. I suspect you have a system voltage issue. You could start by confirming your battery cables are clean and tight. You might have a loose connection internal to the battery, it happens.

-Rod

 

All that is consistent with low battery voltage, my guess,

With the A/C on, blower on HI the alternator/battery/system does not supply enough to maintain 12+vdc (14.4 charging). When it sits at rest, with no load, the battery picks up surface voltage/current, enabling reset.

You electrical system needs a thorough checkup.

 

battery not holding charge, alternator not charging

 

this is obviously either a battery issue or a computer issue.