Fixing my low air light, thought Id add a buzzer but couldnt make the buzzer work.Not enough volts. Everything in the big centre instrument cluster seems to run at around 6 to 8 volts depending on whether engine is running. Its a 12 volt system. Is there a resistor or something to reduce voltage? I know some pickups etc have reduced voltage to gauges etc.Never figured out why though. Checked voltage in other LH panel,at battery etc,its like 12.8 volts as it should be.
Not familiar with the truck but one panel having 12V and other does not, I would say there is some corrosion in a connector or wire
Bad power supply.
Definitely 12 volts. When you fold the switch panel open there is a row of circuit breakers to the right of the switch panel. The strip that the breakers are attached to holds the switch panel open. They all should have 12 volts with the key on. The power comes in from the battery to the ammeter then to the key switch then to the breakers.
Well this has progressed to where the light will not work either. Theres 12 volts to the terminals when theyre disconnected from light but it goes to 0 when light is attached. Light works fine on an independant test. So I think either the circuit breaker supplying power or the low pressure switch is faulty ie cannot supply amps. Cannot find the low pressure switch.Or identify (so far) the circuit breaker. When I pull back the center dash panel theres circuit breakers on a triangular aluminum panel on the right. Says low air alarm is #23(I think)But there arent 23 breakers there. And the breaker with green wires(its green to light) dont seem to change anything when I put voltage to those wires. So Im back to trying to find the switch. If I cannot find it(seems like it must be there!) im going to plumb one in behind main pressure gauge I guess.Input hoped for.
You have a next to nothing ground for that panel. Low air switch if feeding power to the light is also the feed for the Buzzer.
ive tried that. Alternate ground does not change anything.All other things work fine,power and ground seem fine on panel. The light has one lead going to ground( which ive tried substituting to another ground),and one lead going into harness which assumably goes tolow press.switch which i have not yet located.
How far did you access a Ground, the entire cab may no longer have a effective ground. Low volts indicated what is volts at Alternator, if normal is one of Two things, Weak Ground or seriously compromised Positive Cable feed.
I put a Valvac low air light/buzzer combo on a Ford. For me, the low air switch has only one terminal and goes to ground when air low. So, you have ignition “hot” to one side of alarm and the other terminal on alarm goes to low air switch (ground). Not sure if yours runs that way. (not sure if that helps or just gums up the thread )
Finally found the switch. Buried behind heat plenum to dash. Of course. Cleaned up contacts(12 inch needlenoses to put wire back on) and all seems to be as it should be. Thanks for all replies.
Mine was wired so juice goes thru switch then to alarm then to ground.Could be done either way I guess..
Good deal!