[Steve03986]

To install an aftermarket HU in an 03 or 04, you need to bypass the MOST. I installed a single DIN radio and a new amp, which went in the frunk. I ran the amp wiring through the firewall opening under the steering wheel.

The factory amp has two connectors - one is the MOST from the factory radio and the other is for the speakers. If you disconnect the large plastic speaker connector from the factory amp, you can connect the speaker leads from the new amp to the existing speaker wiring.

Alternately, if the new HU has a built-in amp, you may be able to run the speaker wires through the firewall opening and connect to the existing speaker leads.

In either case, however, you have to disconnect the factory amp.

Hope this helps.