UM4 (A3) ● Confirmed

Cadillac · Regular Production Option

AM/FM stereo, 8-track or cassette w/ CB, digital display

Years 1978–79 Models 3

Also described as AM/FM sig-seek stereo w/ cassette (& CB per CLC)AM/FM stereo w/ cassetteAM/FM stereo w/ cassette (& CB)

Documented applications

DeVille / Calais →

• 1978 ● Confirmed

  All

• 1979 ⚠ Disputed

  Mileposts Seville prints UM4 against its 8-track row and UM5 for cassette+CB — radio codes partially conflict

Fleetwood →

• 1978 ● Confirmed

  Introduced on Brougham & Seville first

Seville →

• 1978 ● Confirmed

  Brougham/Seville only at intro

This page aggregates every documented appearance of UM4 (A3) in the Cadillac reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.