[Mike]

Is it for the chassis or the house? Is it working?

While an annunciator light is nice, if the bulb is inop then the functioning of the regulator has to be verified the old fashoined way by measuring voltage with the engine running and with the engine off.

[Michael]

That is a good quesion. I am not certain. I am assuming for the “house batteries”.. since they are not getting charged. My inverter took a dump a month or so again. I have had some electrical issues.

I have a volt meter. How would I go about testing if the voltage regulator is good or bad?

Thanks,

[Robert]

I have to make some assumptions and the answer is based on those.

I assume you have a large alternator mounted at the rear of the engine, gear driven, that supplies charging current to the chassis batteries when the bus is running.

I assume the regulator shown is for the second alternator which supplies charging current to the house.

Or vice-versa. It really doesn;t matter if I have it reversed for the answer to be accurate, but you need to know which is which, if for no other reason than to be able to trouble shoot issues.

Your chassis batteries and your house batteries should be separate from one another electrically. In other words my final assumption is your converter did not use one set of batteries for the entire coach, both house and chassis.

Start the coach and put it on high idle. Measure the voltage at the house batteries. If the house is a 12 volt system the voltage should be 13.6 to 14.2 volts. If a 24 volt house system it should be 27.2 to 28.4 volts.

Measure the coach batteries. The coach will have a 24 volt system and it should read around 27.7.

Turn off the coach and wait a few minutes. About the time it takes to drink a coffee. Measure the house. It should read around 12.6 to 12.8 volts assuming you have no loads such as lights etc.

Measure the coach batteries. The voltage should read around 25.4 volts.

If there is no difference between the battery voltage when the bus engine is running and the voltage when it is not running it is probable the charging system for that set of batteries is not functioning. If that is tru diagnosing the problem is the next step.

Usually that vintage coach was built with converters which were used for charging and later models got inverter / chargers. To try to add an issue into this question can get difficult because not all “upgrades” were done properly.