[ROVERNET - UK] Fuse problem

Fletcher gofanu at usachoice.net
Mon May 7 16:26:46 BST 2007

You are looking at  circuits fed by Green wires = IGN switched and 
fused. Find any branch points of that circuit (starting at the fuse box) 
and disconnect all but one of the wires; see what works and what 
doesn't. Then switch which wire is connected until you know which branch 
blows the fuse. Then follow harness to another node and do the same. 
There are only a few such nodes - at fuse box, at junction of rear 
harness to main, a couple under dash. There are NO connections hidden in 
the harness.

Common source of this circuit failing is a bad park mechanism in the 
wiper motor - always hot woth key ON;  and the instrument voltage 
stabiliser under the dash.
Cars with rust repair to the RH undersill frequently have POP rivets or 
sheetmetal screws that have worn through the harness and shorted various 
combinations of wires to the rear lamps - will drive you nuts as it 
changes all the time!

NEVER go near a live circuit with an ohmmeter. Ammeters are OK but you 
have to hook them up in series, useless for first order diagnostics. Use 
a voltmeter and measure from hot to a fixed ground to find voltage drops 
that will tell you if there's power, if there are bad connections, if 
something is pulling more power than it should. Voltage on the hot side 
of a device should be within 0.5v or less of the across battery system 
voltage. Less indicates serious trouble.


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