I have had great success using this forum to diagnose and
fix problems with my inherited '98 SL2 in the past, and am now hoping someone
can help me out with a very odd problem.



Recently, the electrical system has taken to going completely dead without any
sort of warning or symptom.

The car ran fine in the morning, but when my wife went to run some errands, the whole electrical system was kaput. I jumped it, and the engine started right
up. Let it idle to recharge the battery because I assumed it was either
the alternator or a bad battery (had a couple unfortunately), and it ran for about 15 minutes and died again. </span>At this point I thought it must be the alternator,
however, I tested the battery, and it is 100% good – full charge, over-spec
cranking amps, no drainage at all. </span>I may
be wrong here, but to me that says the alternator is working fine since the
battery would have been drained if the alternator wasn’t functioning. </span>Once I put the battery back in the car
cranked right over without issue. </span>I’d
checked that all the terminals and contacts were clean and tight before I
removed it, so I’m at a loss as to what is going on unless I have a short in
the battery leads. </span>Does anyone have any
suggestions and/or experience in replacing the battery leads?



Thanks!



Nome_man

1998 SL2

149,000+ miles

To be sure of a good battery/alternator charging system either take the car to an auto store that can test the battery/charging system free and/or post your voltage readings here. Batteries will read at least 12.5v, engine idling 13.7v, above idling 14.5v, all measured at the battery post (give or take a few tenths of a volt for each measurement). Any lower readings would indicate either a battery on its last legs or the alternator is faulty. The other contrbuting factor to low voltage may be a loose or worn belt tensioner that won't keep the serpentine belt taut enough to allow driving all the accessories. You should not be able to depress the belt down between pulleys easily and if you can then the tensioner will need replacement. If all is fine then post any results so more suggestions can be given.

I did take the battery to a parts store and have it check out by them. On the counter it was reading 13+ amps. The serpentine belt is taut, but if I press hard I can get some give between pulleys (I pushed between the block and alternator). The belt was replaced only about 10,000 miles ago.

Thanks!

Checking battery for voltage tells you nothing. The battery needs to have a LOAD TEST done. That tells you if the battery keeps it's voltage under load.

Have someone that knows how check the charging system

Be sure the battery cables are tight and clean at the battery

Be sure the battery is not leaking.

Be sure the battery cables are not corroded