Chevy Astro and GMC Safari Forum banner

Electrical nightmare

1349 Views 28 Replies 7 Participants Last post by  jn.mitchell59
Helllo again. This time, Im at a complete loss. I've spent hours trying to find out why my tempgauge, fuel gauge, shift display, & radio stopped working. Also the charge light is still on, even though it's charging. (The shift display quit about a week before the other stuff did.) I've checked ground points, avd all fuses great and small with an ohmmeter, and pored over diagrams searching for a common point that would tie all this together. I'm considering calling the Belle of Louisville, to see if they need a new boat anchor! Help, pls!!
1 - 1 of 29 Posts
Bryancraftyhand wrote: "I don't know of any other form of step down transformer in a car that lowers voltage and limits current running between the engine bay from the battery and alternator, and the cabin area other than fusible links, and breakers. If anyone does, inform us please. "
Definitelly not applicable to jn.michell59's specific case, but there are voltage regulators in some instrument circuits in some cars. I honestly do not know if our oil pressure gauge has such an item, but it acts like it at times, with the fluctuations.
If the '3volts' was measured with a good DVM, it could be just a bit of leakage past a transistor switch into an open circuit.
While working on industrial machinery which very commonly has 24 VDC control circuityr, I have seen technicians who thought they were seeing 20 or 25 volts on an autoranging meter, when it was actually 0.2 or 0.25 volts. These small residual voltages can be very confusing, if a small load is not being applied to drain off any leakage.
If it is measured with an analog meter ( which does supply a vary small load by it's design) , I would suspect the measured voltage would drop to very near zero.
DVM's can be sometimes too sensitive to for some measurements that have small leakage voltages present.
Rod J
See less See more
  • Like
Reactions: 1
1 - 1 of 29 Posts