I just want you guys to know the quality of information I get from people who JUST WANT TO HELP. They have no agenda, no interest in being right or wrong. They just want to help a fellow truck enthusiast. This is from a long time electronic engineer friend of mine who designed a circuit, then decided we needed something more. The reason for the narrative is that I think you guys think that conflict and misery is just a normal thing we have to suffer through in order to get to the answer. It is not. Not by a long shot. Read:
Hello Deve,
Woke up in the middle of the night and the circuit we
worked on will not work...... There are three
variables required to make it work properly: #1
Ignition switch on, or "13.8 Volts". #2 Oil pressure sense
"Shorted or Open" AND the missing variable #3 an "Engine
Running" OR NOT running, either a 13.8 V High or Ground
Low. The way the circuit is now drawn it's going to do
the same thing as you originally had it!!....alarm with the
ignition switch on until the oil pressure goes up. You
will "have to have" an engine running signal for it to work
as you want.
I suggest using the alternator charge indicator "light" as
the engine running indication. Most alternators use
the field excitation wire with a Light Bulb in series to the
ignition switch as the Charge indicator. How this
works is: When the engine ignition switch is turned
"on" it applies excitation voltage to the alternator field
winding through the light bulb. The bulb lights up due
to opposite side of the field winding being connected to
ground. However, when the engine starts, and the
alternator spins and puts out voltage, the field winding
will have voltage induced into it which will "rise" above
the ground originally "seen" by the light bulb and the light
bulb will go out! That's how the "charge
indicator" on the dash works....(If the indicator lamp ever
opens, the alternator will not charge!!! because the field
coil is not producing a magnetic field! (That's why
it's called the "field" winding.)
A disadvantage to the car owner, but $$$ to the mechanic
that puts a new 50 cent lamp in, and charges $135.00 for
"rebuilding" the alternator....LOL
Anyway..... To get a "signal"
to inhibit the "Ahh oo ga" horn, you'll have to use the
voltage across the alternator lamp to control the horn
"inhibit" relay! I'll let you figure the
rest out..... Ha Ha
---
Do you folks understand the difference? I have a LOT of friends just like this. They freely give their information and happily help out the cause because they KNOW that what goes around comes around. God is good and for anyone to think they have a solution better than the time honored tradition of giving of themselves FAILS EACH AND EVERY TIME!
