[6pack] Voltage Stabilizer saga after-action report

Douglas Morris dcmdcm at nc.rr.com
Sat Sep 4 11:57:57 MDT 2010


Interesting FYI. I have been chasing a ghost (i.e. expected) electrical
gremlin all year. Seems that every once in a while, the top fuse ('74
turn-signals etc.) blows for no apparent reason. Put an ohmmeter on the fuse
output, and everything looks fine, no short, a few ohms won't blow a 35-amp
fuse. New fuse in, turn ignition power on, and ... everything's fine again.
Dang! Got me a consarned intermittent. Drive more. Then ... *fssst* fuse
blows. Aha! Maybe whatever it is hard-failed this time. [measure measure]
Nope, no short. All's fine. Rats! New fuse in, turn ignition power on, and ...
*fssst* fuse blows. Oh, now, what the Sam Hill ?! Plenty of resistance in the
downstream circuit with power off, so no short. Fuse blows with power. Rinse,
repeat.
[insert saga of hours of poring over schematics, fiddling with electrical
thingies, and ordering more fuses]
Result? *drumroll* [opens envelope]
The old-style mechanical voltage stabilizer (that's the little whatzis module
mounted to the back of the speedometer housing that provides a constant
reference voltage for the temp & fuel gauges) went from intermittent short to
hard short, but only when power was applied. In hindsight, it should've been
obvious.

Reason I bring this up is that the new voltage stabilizers are solid-state, so
they're not prone to shorting that circuit out.
Oh, yes, you have to pull the speedo to replace it; so if you're ever fiddling
with your speedo (don't say it), just replace that old-style voltage
stabilizer with a new, solid-state one.
Your hands and sanity will thank you.

[deleted: long tirade on the parentage of the engineer who decided to mount
that ... thing ... on the back of the speedo, one of the places my size-13
hands can't get to without loss of skin and loosening at least one unrelated
connector on something else]


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