The 2 leds in question, OX and ALT, have multiple functions. The most
critical is as a warning of drive belt failure for the water pump. The
OX led also comes on separately as a service reminder for the OX sensor.
It does this every so many miles as counted by a separate odometer in
the speedo cable under the drivers floor. It has no direct connection to
the oxygen sensor and means nothing with respect to the oxygen sensor
functioning or malfunctioning. The ALT led also warns of some charging
failures in the alternator but it is possible for the alternator to fail
and this led not come on.

It is never safe to drive with the ALT/BAT warning led inoperative or
always on. This is because this is the only warning you will likely get
if the water pump seizes or the water pump belt fails. (Other than the
flashing coolant temp led and clouds of steam from the blown heads but
that will be too late).

I have often thought that instead of the lame little icon of a battery
for the ALT led car companies should show a stack of hundred dollar
bills going up in flames. This would give a more urgent sense of the
true situation if this led should come on while you are driving. I have
seen more than one Vanagon get junked because the driver decided it was
ok to drive on for a short distance after this warning came on. A
similar flaming stack of currency could be used for the oil led but the
buzzer on the 2.1 models at least gets your attention.

Mark

"MOST,DAVID" wrote:
>
> What does it mean if the two red dash lights that normally stay on when
> starting (until the engine is revved) aren't coming on at all?  I'm
> assuming that the bulbs and associated fuses are good, but I'll admit to
> having done no checking yet.
>
> Thanks,
> David