Product Description
Custom Autosound USA-740 IN DASH AM/FM for a GMC Motorhome
It is heaven
When you take your classic GMC motorhome and go out into the wilds where few people and a lot of buffalo roam. Enjoying the wilderness does not get any better than on open fire, roasting hot dogs and listening to your music.
After you install your USA-740 radio in your classic motorhome, you will know what heaven feels like. You won’t be without your music which makes the beauty of nature and your solitude a lot better.
The USA-740 has the classic touch
With 300 watts of power your motorhome will not be silent. Every nook and cranny will be filled with your sound. Plus, the 7 color LCD light show uses Bluetooth to dim the lights.
Then the antenna draws in those Am & FM radio stations to be displayed on your RDS tuner. The tuner also displays the song and artist’s names. A USB port connects the MP3/WMA/FLAC/WAV audio options. Also, there is a direct CD control.
In addition to all of this the USA-740 comes with a four way fader, 5 channel RCA preout, 2 AUX input ports and a subwoofer preout. Not to mention the audio controls including treble mid and bass with volume.
If that isn’t enough, the digital clock keeps time even after you have taken your watch off. With lifetime customer support your Custom Autosound USA-740 should always perform at peak levels.
Once you are in heaven
You won’t want to leave. After you install the Custom Autosound USA-740 into your classic GM Motorhome you will find your heaven as soon as you switch the radio on and hit the road.
The solitude of being out in nature with no neighbors won’t bother you either. You have your home, your radio and your music to keep you company.
Frequently Asked Questions About the USA-740 IN DASH AM/FM for a GMC Motorhome
Is this radio made specifically for the GMC Motorhome?
This listing is the version made for the GMC Motorhome, designed to go into the original dash opening. Custom Autosound says its radios fit without altering or cutting the original dash.
What if my GMC Motorhome has air conditioning?
The Factory Air option tells us which dash layout your GMC Motorhome has, so pick Yes if it has factory A/C.
What features does the USA-740 have?
The USB port plays MP3, WMA, FLAC and WAV files from a flash drive. There are two auxiliary inputs, a front mini jack and a rear RCA.
What do I get with the USA-740 in my GMC Motorhome?
Bluetooth is built in, with a microphone included, so you can stream music and answer calls. The AM/FM RDS tuner holds 25 presets (15 FM, 10 AM) and can auto-store the strongest stations.
Will it work with a 6-volt system?
Which add-ons are offered with this radio?
You can add a front dual voice coil speaker, a rear 6x9 speaker pair (Custom Autosound 6x9 Speaker Pair and Upgraded Pioneer Speaker Pair), and a hideaway antenna right from the options above.
USA-740 specifications
- Bluetooth built in (streaming and hands-free calling)
- 300 watts peak power (45W x 4 RMS, 2-ohm stable)
- AM/FM stereo tuner
- 2 AUX inputs (3.5 mm front and RCA rear)
- USB port
- Direct control for optional CD-1
- 5-channel RCA pre-outs including subwoofer pre-out and control
- 15 FM and 10 AM presets
- 7-color LCD with dimmer; RDS station/song/artist display
- DSP EQ; auto-store presets
- Electronic tuning and volume; separate bass/treble; 4-way fader; L/R balance
- Power antenna lead; digital clock
- USA/EUR/JAP/RUS tuner capability (USA default)
- Custom Autosound 2-year manufacturer warranty
USA-740 wiring and tech tips
Use this as a head-unit reference for power, ground, antenna, speakers, and amplifier connections. Always match the printed diagram that ships with your unit if it differs.
Power and ground (typical Custom Autosound harness)
| Function | Wire color |
|---|---|
| Ignition / ACC +12V | Red |
| Battery / constant +12V | Yellow |
| Ground | Black |
| Power antenna | Blue |
Ignition and power-antenna leads are commonly fused at 1A on the harness—confirm against the guide that ships with your radio.
Speaker wiring (typical)
| Speaker | Wire color |
|---|---|
| Left front + / − | White / White-Black |
| Right front + / − | Gray / Gray-Black |
| Left rear + / − | Green / Green-Black |
| Right rear + / − | Violet (or Purple) / Violet-Black |
USA-740 extras
Expect antenna, USB, microphone (Bluetooth), CD-1, and subwoofer RCA connections in addition to front/rear line outs. Use the front 3.5 mm AUX or rear RCA AUX for wired sources.
Suggested order for a classic GMC Motorhome
- Disconnect the vehicle battery before any wiring.
- Connect ground first, then constant (yellow) and ignition (red).
- Connect the antenna plug and the blue power-antenna lead if your car has a power antenna.
- Wire all four speakers, matching polarity.
- If using an amplifier, run RCA cables from the front/rear (and sub on USA-740/USA-850) pre-outs.
- Reconnect the battery and test radio, speakers, and charging system voltage.
Tech tips for classic GMC Motorhome
- This radio is sold for the factory GMC Motorhome opening used in classic models—do not cut a modern DIN rectangle if you want a stock look.
- A poor ground is the most common cause of whine or weak audio; scrape paint at the ground point and use a star washer.
- If AM reception is weak, check the antenna mast, cable continuity, and that the antenna plug is fully seated.
- Vintage Car Radio does not install radios. If you are not comfortable with 12V wiring, use a qualified installer.
USA-740 manuals
Download the manufacturer guide for operation, safety, and the official wiring diagram. You can also browse our full library on the Manuals page.
Vintage Car Radio does not offer installation. The manuals are for do-it-yourself reference or to share with your installer.
Two-Year Custom Autosound Warranty
All Custom Autosound radios sold by Vintage Car Radio are backed by a 2-year manufacturer warranty from Custom Autosound.
Radios are checked before shipping. If something is wrong out of the box or under warranty, call us at 844-802-4499 or 574-226-6676 and we will help coordinate with the manufacturer.
Vintage Car Radio does not offer installation services. Refer to the Manuals and Wiring / Tech Tips sections for manufacturer guidance, or use a qualified car-audio installer.
FAQ — classic GMC Motorhome USA-740
Will this fit my classic GMC Motorhome without cutting the dash?
It is built for the original radio opening used on classic GMC Motorhome models. Compare your dash opening and bezel to the product photos. We do not modify dashes in-house.
Does this radio have Bluetooth?
Yes—Bluetooth is built into the USA-740 for streaming and hands-free calling.
Do I need an amplifier?
Many owners run speakers directly from the radio. Pre-outs are there if you want more volume or a subwoofer later.
Do you install the radio?
No. Vintage Car Radio ships the unit and documentation; installation is DIY or by a shop you choose.
What is the warranty?
Custom Autosound radios include a 2-year manufacturer warranty. See the Warranty section for details.
Need help?
Call 844-802-4499 or 574-226-6676.
Specs
Wiring / Tech Tips
Manuals
Warranty
Two-Year Custom Autosound Warranty
All Custom Autosound radios sold by Vintage Car Radio are backed by a 2-year manufacturer warranty from Custom Autosound.
Radios are checked before shipping. If something is wrong out of the box or under warranty, call us at 844-802-4499 or 574-226-6676 and we will help coordinate with the manufacturer.
Vintage Car Radio does not offer installation services. Refer to the Manuals and Wiring / Tech Tips sections for manufacturer guidance, or use a qualified car-audio installer.
