Packard Forum Index » V-8 (1955-56)

1955 Packard 400 instruments reading low

Converted to negative ground to accept solid state voltage regulator. Which seems to be working correctly. Input +/- 12 volts, output steady at 5 volts, via meter, and 12-volt test lit but dim.
Connected limiter output directly to gas gauge. Gauge came off peg and ruse to empty dot. Tank has 10 + gallons in it. Same for temperature gauge . Moves off peg to cold dot with fully warmed up engine. No response from temperature gauge. Using tap beneath oil sending switch for mechanical gauge. Oil pressure approx. 30 psi at warm idle
The same symptoms were present before changing to negative ground. I have no clue as to what to look for next. Any and all comments deeply appreciated!

Happy
(maybe not so much)

How is the electrical condition of the terminals connecting to the load side of the voltage regulator? Sometimes there is oxidation that needs to be cleaned off the wire terminal before it is reconnected, that previously was not a problem.

You didn't mention what type solid state regulator you are using and how the hookup compares to the original unit. The symptoms almost sound as if the regulator is not providing enough current or voltage to run all the gauges. Is the regulator running hot?

Just to confirm, the new regulator output should be feeding three gauges that would be in parallel so all are getting voltage at the same time like the original regulator provided. Did you measure the 5v at the gauge terminals and get the same voltage at all of them?