Audiovox UPA224 User Manual

UPA224/UPA424

7

Before finishing the installation, perform the 
following tests to make sure the wiring is correct 
and everything is operating properly.

When wiring is complete, reconnect the battery 
negative terminal.

Turn on the receiver, but do not turn up the 
volume. The amplifier power light should come 
on. If not, check the REM and +12V wires. Turn 
up the receiver volume slightly. All speakers 
should operate. If not, check wiring connections 
at amplifier and speakers.

These tests make sure the speakers are 
connected properly. If speakers don’t play at all, 
one (or both) speaker wires may be 
disconnected.

.

Amplifier does not 

turn on

No power to +12V terminal

Check fuse(s)

No power to REM terminal

Check head unit fuse(s) and wiring

Blown main fuse at battery

Replace fuse and identify cause of failure

Blown fuse at amplifier

Replace fuse and identify cause of failure

Faulty ground

Reground main power ground to bare metal chassis

Volume control too 

sensitive

Input level control adjusted too 

high

Readjust the input level

Distorted sound

Input level control adjusted too 

high

Readjust the input level

Blows fuse(s) at 

amp

Power wires connected backwards

Reconnect power wires properly

Internal problem with amp

Take unit for service

Engine noise / 

Alternator whine

Ground loop(s)

Use good quality shielded RCA cables

Faulty ground at amp

Reground amp to clean bare metal chassis

Faulty ground at head unit

Reground head unit to clean bare metal chassis

Inductive coupling

Reroute RCA and/or speaker wires away from factory 

harnesses

Input level on amp set too high

Readjust input level

Poor bass response Speakers out of phase

Check speaker polarity; reverse the connection to one 

speaker only if two subwoofers are connected to the 

amplifier.