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If you are going to get a new multimeter, get one with a current clamp, so you can measure high currents easily and safely.
In meantime, disconnect the alternator and check if the battery still gets drained (without running the engine). If some of the diodes in the alternator failed (have a short), it can cause the battery to discharge, and, of course it can't charge the battery.
If you are going to get a new multimeter, get one with a current clamp, so you can measure high currents easily and safely.
In meantime, disconnect the alternator and check if the battery still gets drained (without running the engine). If some of the diodes in the alternator failed (have a short), it can cause the battery to discharge, and, of course it can't charge the battery.
Appreciate the input.
new meter ordered and I’ll be going thru suggestions one by one.
thanks 👍
May be the same issue I've had, Seems only to affect early cars (1999 or 2000). Something about the SLS wiring or circuitry is different in these early cars, I have never figured out what or why, but my experience is that low voltage causes havoc w/ early SLS systems.
Basically what I believe happens is ...
-- the car has a low battery, on an otherwise sorted vehicle.
-- Once the battery is low, the low voltage causes something with SLABS or SLS system to happen whereby then compressor starts making a weird stuttering noise, or valves click and are opened / closed repeatedly...
-- This happened when car was locked, or unlocked, either way -- but while sitting in garage overnight.
-- which then kills the battery. And I mean dead-dead. I have no idea why a low voltage condition triggers this.
Try replacing your battery first if everything else checks out. Even if battery tests good.
You could try disabling SLS (fuse/relay/ground) to troubleshoot. In my case I went down a rabbit hole (on a 38K mile 2000 D2) looking for SLS issues, but there were none, it was a low voltage problem.
May be the same issue I've had, Seems only to affect early cars (1999 or 2000). Something about the SLS wiring or circuitry is different in these early cars, I have never figured out what or why, but my experience is that low voltage causes havoc w/ early SLS systems.
Basically what I believe happens is ...
-- the car has a low battery, on an otherwise sorted vehicle.
-- Once the battery is low, the low voltage causes something with SLABS or SLS system to happen whereby then compressor starts making a weird stuttering noise, or valves click and are opened / closed repeatedly...
-- This happened when car was locked, or unlocked, either way -- but while sitting in garage overnight.
-- which then kills the battery. And I mean dead-dead. I have no idea why a low voltage condition triggers this.
Try replacing your battery first if everything else checks out. Even if battery tests good.
You could try disabling SLS (fuse/relay/ground) to troubleshoot. In my case I went down a rabbit hole (on a 38K mile 2000 D2) looking for SLS issues, but there were none, it was a low voltage problem.
thanks for this. If the other tests fail to identify the issue I’ll chase you down that rabbit hole !
incidentally, is there anything audible or visible around the suspension that I could see/hear that might indicate this as the culprit ?
You could also unhook the red lead from the alternator while the truck sits to isolate it as the source of the current draw. This might steer you towards SLS or alternator. Be super careful and isolate it well, as it could weld itself to something and/or start a fire if you let it touch things.
06-05-2023, 04:02 PM
