This manual might help, but it's for 1979 models. I thnk the 1979 columns had steering wheel locks, and the 1971 ones didn't. The horn button may be the same.

http://oldcarmanualproject.com/manuals/GMC/1979/LTService/03B/index.htm


Gord 🇨🇦
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1954 1/2 ton 235 4 speed