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How it works Posted by Bill Homer [Email]  (#3427) [Profile/Gallery]
(more from Bill Homer) on Thu, 24 Feb 2011 13:19:47
In Reply to: mildly contagious, weston, Thu, 24 Feb 2011 11:44:18 Members do not see ads below this line. - Help Keep This Site Online - Signup |
It's a very simple circuit: switched 12V power (hot when ignition is on) -> light bulb in dash -> wire to pressure sensor -> pressure sensor -> ground point. The pressure sensor conducts when the pressure is below a certain preset point, will allow current to flow through the bulb when the circuit is "hot" (not energized when the ignition is off).
If you want to test the bulb, just ground the wire that attaches to the sensor and turn on the ignition; the grounded wire completes the circuit illuminating the bulb.
I changed mine with a deep well socket (forgot the size) on about a three inch extension - did it "partially blind" by feeling around from the top.
Like Derf, I was quite surprised with the silent failure mode. Every older car that I have previously owned had a failure in this sensor, usually cracked plastic, that typically sent hot oil squirting around the engine compartment. This occurred several times on my C900 in the 20+ years that I owned it, but the dummy light illuminated due to low oil pressure at the leaking sensor.
posted by 208.70.1...
, Tue, 22 Feb 2011 16:49:29, Thu, 24 Feb 2011 13:19:47 <-- Viewing This Message
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