Yes, best to test every pin for signal, with a test light (preferably), an analog voltmeter, or a digital voltmeter.
There may be "standard" colors and signal pin locations, but any particular connector or coach may not follow them.
That said, "7-way RV Standard," per this link
, is common.
Page 5-159 of the 2001 Executive Owner's Manual (link here
) confirms the usual for your coach. That is, it was not wired to a 7-pin standard. Instead, as it came from the factory it had these signals:
This is common for older coaches. The tow dolly expects these signals:
To make the conversion between a three-wire (LT, RT, Brake) and a two-wire, someone probably installed a three-to-two converter upstream of the hitch connector. You find it by following the wiring from the connector towards the front of the coach. Somewhere within three feet of the connector you will find a block of metal or plastic about the size of a pack of cards. That's the converter. A failed converter will cause the symptoms you observe (it is not the only cause, though). You can get a replacement converter at this link