The station began in the summer of 1984 as
KKJJ 103.9, a Class A station licensed to
Payson, and would remain until 1987, when they got the approval and completed the move to 104.3. The original format was country. Callsigns since then included first
KAFM then
KRIM then
KBZG which were in use during part of the KBZR simulcast. The KRIM calls once dropped for KBZG were picked up later when KRIM-LP took them. Previous formats include country, an
AOR/
Modern Rock/
CHR format called "The Blaze", a simulcast of CHR/Rhythmic
KBZR-Coolidge (later
KPTY-Gilbert), a return of the "Blaze" format (under the new name "CD Rock"), Traditional Oldies as "K-Best", and a ’60s-’90s Rhythmic Oldies format, under the name "Arizona Jamz", featuring sweepers with "
Beavis and Butt-Head" sound bytes. Carey Edwards, an established Phoenix air talent who had most recently been programming
Rhythmic Oldies KGMG "Mega 106.3" in
Tucson, was brought to the station. Soon after his arrival, allaccess.com reported that KAJM would be "relaunched" soon. On April 20, 2001, at 5:00 pm, as Edwards applied the formula from KGMG — KAJM became "Mega 104.3 & 99.3". Since then, the station has shifted towards a gold-based Urban Adult Contemporary direction in part due to having a sister station in
KNRJ, whose playlist and direction features an Urban Contemporary direction with a heavy emphasis on Classic Hip-Hop. As of June 2011, KAJM has picked up competition from
Gold-based Rhythmic AC KYOT-FM, a move that prompted KAJM to rechristen its slogan to "Arizona's #1 Old School Station" to counter KYOT-FM's library of R&B/Pop/Dance classics (KYOT-FM has since flipped to
adult hits). In July 2022, the station revived the "Jamz" moniker it had used before rebranding to "Mega", and began to be alternatively branded as "Mega 104.3 Jamz", with no change made to its format. On February 5, 2026, KAJM began simulcasting on translator K257CD 99.3 FM and the HD3 subchannel of
KMLE; the new signal originates from
North Mountain, Phoenix, giving it better reception in Phoenix than the existing
rimshot signal. On February 26, the
Mega format moved exclusively to K257CD/KMLE-HD3, and the station began
stunting with a looping announcement promoting the frequency change, and that a new format would launch on KAJM at 3 p.m. ==Move==