Scions:
trying to work out my nonoperative spitfire horns, fuse is OK (by
inspection and ohmeter, same circuit as ignition switch illumination and
headlamps, they work),
I appear to have two problems
1) the purple-black wire (disconnected at the relay) does not become
(negative) ground potential when the horn button is pushed- I looked at the
"horn brush", I'm not sure how it's supposed to work even after inspecting,
but I suspect it just becomes a closed switch when compressed by the horn
button, didn't check it in any other way since I was looking at other
stuff, but I have to say that the system looks unreliable, there is no
locating system to be sure the button is oriented correctly to be in
contact with the brush, anyway, how does this part of system usually fail?
2) the relay seems OK- grounding the bottom pin (where the purple-black
wire was) results in positive volts at the purple-yellow wire's pin, but...
3) the left (high pitch) horn gives a single sort of chirp when I do this,
it does the same when I disconnect the purple yellow wire from it and
supply 12v directly from battery. Interestingly, disconnecting the left
horn purple-yellow results in the right horn responding to the ground the
relay maneuver just fine- stuck the ohmeter on the horns (purple-yellow
wires disconnected), resistance quite low in both, but my ohmeter is a
cheap one with only a 1000 ohm scale, precision may not be enough to
differentiate and I suspect the left horn is a short- I'll be happy to fix
the steering wheel end of the system and live with one horn for the short
term, but do they act this way when they short?
4) there's a black-green (fourth) wire connected to the horn relay, not
shown on the wiring diagrams I have, anyone know what it is?
thanks
Joe
Joseph R Schneider Web Page http://pubweb.acns.nwu.edu/~jschneid/JRS.HTML
76 Spitfire 1500 FM45587UC VTR #11526
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