Chrysler Repair: 2005 Jeep Grand Cherokee: cluster misbehaving, jeep grand cherokee, powertrain control

Question
QUESTION: When I start my car the instrumental lights all come on and the gauges go off, then they all reset.  This has happend 3 times over 2 days.  The check engine light stayed on the 1st time, nothing stayed on the 2nd time and the engine and airbag light stayed on the 3rd time.  My mechanic is telling me that it is either the PCM or the body control module, but I think it is the ignition switch.  Any advise?

ANSWER: Hi Tamara,
My belief is that the electronics of the instrument cluster may be the culprit. You should be able to do a diagnostic readout using the ignition key in the switch as follows:"lock-on-lock-on-lock-on and leave on" doing that in 3 seconds or less elapsed time. Then watch the digital readout at the odometer window to see if a 4-digit number(s) preceded by a capital letter appears in place of the normak reading in that display. Tell me what it is and we'll go from there.
Until you do this test there is no point in focussing on the body or powertrain control modules.
Roland

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QUESTION: Roland,

I tried this test 3 times and did not get any number.  I should mention that
the check engine light was not on when I tried this (maybe there are no
codes stored right now?).  Also when I did this test each time when I left it
in the on position after a few seconds the engine light blinked and singed
a couple of times.  I am not sure if this is normal.  I also checked the
codes the mechanic gave me, B2100, B212d and this seems to indicate
the ignition switch

Answer
I checked out the two codes. Are you sure it is B2100, because I don't see exactly that code?
I do find the B212D and it has several possible causes which look pretty simple to check out. If  you will give me your email address I will copy and attach the pages to an email, about how to trouble shoot that if you or your mechanic want to check it out. It is not the ignition switch but rather a circuit that comes out of the switch which involves a relay, fuse, and some wires. Let me know if there is a different number for the B2100.
Roland