charge trek VIII -"Scottie, break out the ETM!"
Alrighht .... were you all hoping this would go away by itself? me too.
For those of you who didn't make it through the first seven (!) episodes...
...the story so far...
Basically, an inexplicably bad charging system on my '89 525i has led me to investigate the circuit that connects to the D+ terminal at the alternator, which reads 1.5V (should read +/- 12.5V) with the engine running. The meter shows that there are 48.4 ohms of unwanted resistance somewhere on this circuit that I have to find, preferably before my workspace turns into planet Hoth.
Let's have a look at that circuit in the trusted Bentley that we all have a copy of, shall we?
The link to the instrument cluster is for the charge light, which works as it should. Hmmmm... better have a look at that 'uncoupling diode' and the 'unloader relay'. As it turns out i have a couple - both of which seem to work, each with it's own clue.
An unloader relay is designed to reduce draw on the battery from vehicle electrical components during vehicle starting so as not to overtax the battery, from what I can gather. I think it activates the diode which regulates voltage to certain circuits. (?.....help?)
Time to break out the ETM...
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