Warning Alarm

[Sea Bitt]

Warning Alarm
I have a crusader 1980 220 hp Chev 305 with an added Alarm buzzer for over temp and or low oil pressure. Everything was working OK and would buzz when engine off (no oil pressure) and be silent when engine running. The issue is the Alarm circuit is still energized when the engine is running but the voltage is approximately half or around 6 volts so the buzzer will still make a muted weak sound.

I think it is a bad sender for the low oil pressure or over temp. The weird thing I pulled the wires off both sender units (orange wire) and the buzzer still had the 6 volts showing. The temp and oil pressure gauges work fine.

How do I troubleshoot this? To eliminate a wiring short or issue was going to run a separate wired from the two senders, one at a time, directly to the buzzer to see what happens and take the wire off from the wire harness for testing. Does anyone have a better idea what could cause this?
Twin motors and only one is doing this? It could be possible the wire harness was moved or disturbed due to standard spring commissioning? I checked this engine with the other and the wiring looks the same?

Thanks,

 

[makomark]

the ALARM system uses SWITCHES not SENDER units (so the gauges are independen of the alarm).....and the normal installation is for the switches to be "in parallel" - this means any switch turning ON will turn on the buzzer.

not knowing how and where the 'volage' was measured means it don't help much....it is very common to find "battery voltage" on either side of the buzzer, with the engine running, and the alarm not sounding.....

for troubleshooting - make sure the buzzer works by gounding the switched side lead when the key is on.....(this normally happens when the key on turned on due to the oil pressure switch being ON )...

the coolant and gear switches are best tested once removed....