Please read [very carefully] my Case-Contrasted (UPPER) replies within your test. NOT yelling, okay? ADDED THIS WAY FOR CLARITY. Thanks!
You can't have both continuity and voltage at the same place unless you're measuring them differently.
THEY WERE MEASURED DIFFERENTLY: CONTINUITY AND DC VOLTAGE, SEPARATE TESTS.
I THOUGHT I MADE THAT CLEAR, AS LUDICROUS A 'PROCEDURE' AS THIS MAY HAVE APPEARED TO YOU.
You should have continuity between the battery and large starter terminal, but no voltage difference between those two points.
THERE IS NO DIFFERENCE IN VOLTAGE AT THESE TWO POINTS.
CONTINUITY IS: 0.00 (RINGING. IT'S A FLUKE II).
VOLTAGE IS SAME AT BOTH POINTS WITH - TEST TERMINAL TO GROUND/-TERMINAL.
AGAIN, I THOUGHT I MADE THAT CLEAR TOO.
If you measured the voltage at those two points with the meter negative probe on ground, that would make sense. There's no reason to expect that fat cable to be damaged.
AGREED. IT IS NOT DAMAGED, BECAUSE CONTINUITY IS SOLID, WITH RESISTANCE OF 0.00 OHMS.
Similarly, there should be continuity between the battery positive terminal and the generator's output terminal. You found none.
(SIMILARLY? IT'S REFRESHING TO SEE A TECHNICIAN WHO CAN SPELL, AND WRITE. NO PUN!)
CORRECT. THERE SHOULD BE, BUT THERE IS NONE.
You should find 0 volts with your meter probes on those two points, but if you measured AT the generator with the meter negative probe on ground, you should find 12 volts.
THAT'S MY POINT---NO VOLTAGE AT ALL WITH - PROBE TO GROUND! HOWEVER, IF I PUT - PROBE TO + BATTERY TERMINAL I GET THE SAME DC VOLTAGE READING AS IF I WERE CHECKING THE BATTERY.
SOMETHING IS DEFINITELY WRONG HERE.
The confusion is did you measure "at" or "between"?
'AT' (WITH - PROBE TO GROUND/- BATT. TERM.) FOR VOLTAGE: NONE!
'BETWEEN' FOR CONTINUITY: NONE!
Continuity measurements must be taken in circuits that are not powered up, otherwise you will get some false readings.
SOME FALSE READINGS, YES; BUT NEGLIGIBLE FOR PURPOSE OF A 'NO START' PROCEDURE. AGREED?
While measuring the voltage BETWEEN two points can be useful, taking them AT various points with respect to ground is more informative and easier to understand.
AGAIN, AGREED! I'M SURE THAT I FOLLOW YOU.
Double check the voltage at the generator's output terminal with the meter negative lead on ground.
DID THAT. NOTHING!
First use the battery's negative post for ground, then verify the reading by using the generator's case as ground.
ALL GOOD! NO VOLTAGE; CONTINUITY STRONG.
I think from your readings, you're going to find 0 volts there.
I UNDERSTAND THAT. ***WHAT I DO NOT UNDERSTAND FROM WHAT IS GOING ON WITH MY SYSTEM, AND WHAT I THINK YOU'RE MISSING OUT ON IN THAT POINT, IS THAT I MEASURED DC VOLTAGE BETWEEN BATTERY (+) AND ALTERNATOR (BATT.) TERMINAL WITH + & - LEADS, AND I GOT VOLTAGE READINGS AS IF I HAVE MEASURED AT THE BATTERY, CONVENTIONALLY-SPEAKING. THAT IS WHAT I FIND SO STRANGE. ARE YOU TRACKING NOW?
There are six diodes in the generator. Those are one-way valves for the output current. They let that current flow to the battery, but when it's not running, they block current flow from the battery.
I UNDERSTAND: ELECTRICAL 'CHECK VALVES'.
By reversing the jumper cables, those diodes were "forward biased", and only the minute resistance in the battery cables limited the current. There is a limit to how much current those diodes can handle and that limit would have been exceeded by many times. Most cars have a very large 80 - 120 amp fuse bolted into the under-hood fuse box which might save the diodes, but when two of them short and allow excessive current, they follow that by burning open so the short is gone. The generator is destroyed, but the short is no longer in the circuit, just as if that wire to the output terminal was unbolted.
THAT THERE MAKES A LOT OF SENSE. HOWEVER, IT DOES NOT EXPLAIN [IN MY LIMITED UNDERSTANDING] ***WHY THERE IS VOLTAGE BETWEEN BATT. TERM AT ALTERNATOR (MEASURED AS IF IT WERE THE GROUND) AND THE + TERMINAL OF BATTERY.
IS THE ANSWER TO THIS QUESTION CONTAINED IN ABOVE?
If you don't have a large fuse for the generator, there may be a fuse link wire going to it. That is a small section of wire spliced in that is smaller in diameter so it's the weak link in the chain. The insulation is designed to not burn, and it will be a different color than the rest of the wire.
I'VE SEARCHED FOR FUSIBLE LINKS. I FOUND NONE. DOESN'T MEAN THERE'S NOT ONE THERE THOUGH. UNDERSTOOD.
You test them by pulling on them. If they're good, they'll act like a wire. If they're open, they'll act like a rubber band.
Somewhere between the battery positive cable and the generator output terminal is a break in the circuit.
MAKES SENSE. (POSSIBLY LOCATED BETWEEN BACK OF ENGINE AND FIREWALL OF THIS SCION?)
BUT HOW DOES THAT EXPLAIN THE VOLTAGE I FOUND IN "***" ABOVE?
Many manufacturers use the generator's output terminal as a convenient tie point for the wires feeding other circuits. If yours does that, you might see more than one wire attached there. That would explain the dead starter relay.
ONLY ONE MAIN TERMINAL ON GENERATOR 'BATT' TERMINAL.
Also check the operation of the head lights or dome light. If those don't work either, check for voltage on any of the fuses. The smaller positive wire that is typically bolted to the fuse box may have burned open, or the smaller negative wire bolted to the body may have burned open.
GOOD INFO. THERE ARE OTHER ELECTRICAL ISSUES.
I APPRECIATE YOUR TIME, caradiodoc-FRIEND.
Saturday, July 16th, 2011 AT 9:12 PM