xlrlist01
07-04-2010, 11:07 PM
Having mentioned in the past that the lack of odometer display at ignition off could indicate a failing battery, I have the following observations about when it does seem to display.
To get the odometer to display after ignition off needs the following:
1/ Good battery
2/ The 'keep headlights on' exit delay setting to be on (15 seconds or longer)
3/ Headlights have to be on at the time of switching off the ignition.
So far as I can tell, the odometer displays for as long as the headlights (actually, its the fog lights) are on.
Why Cadillac would link the display of the odometer to the headlight on delay escapes me, but there we are.
What I don't know is, if the battery is poor, do the fog lights stay off too (after ignition off)? If so that would make sense to save the battery's charge.
While observing this, I note also that the charging voltage seems to vary depending on load, so in the summer with no headlights, rear defogger etc. the battery is charged to a lower voltage than it was in the winter. Since replacing the battery, the around town economy also seems to have improved (it was really very bad), I guess this is a by-product of my XLR not constantly trying to fix a sulphated battery.
BTW, the voltage as displayed in the dash seems to stay about the same, but the actual voltage being delivered seems to vary, i.e. the dash reading seems to be more of a health check than an actual voltage.
Also, a sulphated (sulfated) battery is caused by being stored at too low a voltage, use a battery tender if you drive your XLR infrequently, say stored for over two week periods. If the battery is sulphated it will pass most battery tests, the problem is that it charges and discharges too quickly as it has (pretty much irreversibly) lost capacity. Tests of voltage and simple load tests might not reveal a problem, an extended discharge/charge test at a known current will.
To get the odometer to display after ignition off needs the following:
1/ Good battery
2/ The 'keep headlights on' exit delay setting to be on (15 seconds or longer)
3/ Headlights have to be on at the time of switching off the ignition.
So far as I can tell, the odometer displays for as long as the headlights (actually, its the fog lights) are on.
Why Cadillac would link the display of the odometer to the headlight on delay escapes me, but there we are.
What I don't know is, if the battery is poor, do the fog lights stay off too (after ignition off)? If so that would make sense to save the battery's charge.
While observing this, I note also that the charging voltage seems to vary depending on load, so in the summer with no headlights, rear defogger etc. the battery is charged to a lower voltage than it was in the winter. Since replacing the battery, the around town economy also seems to have improved (it was really very bad), I guess this is a by-product of my XLR not constantly trying to fix a sulphated battery.
BTW, the voltage as displayed in the dash seems to stay about the same, but the actual voltage being delivered seems to vary, i.e. the dash reading seems to be more of a health check than an actual voltage.
Also, a sulphated (sulfated) battery is caused by being stored at too low a voltage, use a battery tender if you drive your XLR infrequently, say stored for over two week periods. If the battery is sulphated it will pass most battery tests, the problem is that it charges and discharges too quickly as it has (pretty much irreversibly) lost capacity. Tests of voltage and simple load tests might not reveal a problem, an extended discharge/charge test at a known current will.