Hour meters 1979 37C

[hcalmar]

I would welcome advice. I have researched archived threads to no avail. The starboard power meter stopped working two years ago, port halfway through last season. Bought a new meter and installed it but it did not work. Gave 12 volts to both of the older meters and they run. I do not have fuel pressure switches on either my primary or secondary fuel filters. I cannot tell where the hot lead (#109/port) comes from. It does not appear to come from the ignition. The boat has the original 6-71ti which I think are the Covington version. Thank you.
Hal

 

[Will]

Do you have oil pressure switches?
Will

 

[hcalmar]

I do, two of them in fact. One set goes to the guages and I assumed the other to the alarms? Both guages and alarms work.
Hal

 

[hcalmar]

Any other ideas?
Thank you.
Hal

 

[yachtsmanbill]

Lost the ground. Jumper them with alligator clips for a test. ws

 

[hcalmar]

For the DIYer how do I test the oil pressure switch? Does it supply the ground to the hour meter? Where does the red pos on the hour meter come from? Thanks
Hal

 

[Nick]

Hal, the drawings I have from Hatteras 37 show that line 109 comes from the alternator voltage regulator. looks like it's a No. 14 Yellow conductor and at Terminal Block Port Engine TBPE-4 it connects to the hour meter feed no 109 a 16 gauge red conductor. I think the terminal block is the electrical enclosure mounted to the engine room port aft bulkhead behind the tranny.

Seems odd that both hour meters are out! The ground is a 16 gauge yellow conductor on both meters and connects to the negative bus bar.