1994 Roadmaster Sedan stereo question

[G67RMS]

I have a 1994 Roadmaster sedan. When I got the car almost 5 years ago, only the front speakers worked. The car has the factory cassette deck head unit. The balance and fader switches appeared to work properly. About 6 months ago, the right front speakers are no longer working.

I tend to think this increasing lack of
Stereo functionality seems to point to an internal fault in the head unit. However I don’t know too much about the inner workings of a car stereo. Any thoughts/ideas? Thanks in advance for any help or assistance you can provide.

 

[BuickGirlFromMars]

I have a 1994 Roadmaster sedan. When I got the car almost 5 years ago, only the front speakers worked. The car has the factory cassette deck head unit. The balance and fader switches appeared to work properly. About 6 months ago, the right front speakers are no longer working.

I tend to think this increasing lack of
Stereo functionality seems to point to an internal fault in the head unit. However I don’t know too much about the inner workings of a car stereo. Any thoughts/ideas? Thanks in advance for any help or assistance you can provide.

is your car UQ3 rpo code? check the door frame or the glovebox or the area of the spare tire for a sticker with 3 digit codes.
if you DONT have uq3

This is your radio diagram:

 

[G67RMS]

is your car UQ3 rpo code? check the door frame or the glovebox or the area of the spare tire for a sticker with 3 digit codes.
if you DONT have uq3

This is your radio diagram:
View attachment 48845

Thanks for that diagram. My RPO sticker shows UQ1 and UQ3. I am guessing that means the basic stereo with the 6 speaker set up. Probably the same wiring diagram with a speaker added to the left and right front. Gonna have to get in there and start testing stuff.

 

[02LTD2.0]

....or maybe just upgrade to a modern radio. Treat yourself 😉

 

[G67RMS]

....or maybe just upgrade to a modern radio. Treat yourself 😉

I am torn, my daily driver has a touch screen radio with carplay and all the convenience features. I like that stuff but I don’t like the look of new radios in old cars, figured if I could fix it cheap that would make up my mind for me…..

 

[02LTD2.0]

I am torn, my daily driver has a touch screen radio with carplay and all the convenience features. I like that stuff but I don’t like the look of new radios in old cars, figured if I could fix it cheap that would make up my mind for me…..

I totally understand.😎

 

[BuickGirlFromMars]

 

[G67RMS]

View attachment 48846

Thank you, that is a great diagram. I wonder how that VF PWM SIGNAL wire going to the a/c system is about? Never saw an a/c wire involved with the radio wiring before. I am gonna have to get in there with a tester and see whats going on. I will post my results if I find anything.

 

[HotZ28]

Thanks for that diagram. My RPO sticker shows UQ1 and UQ3. I am guessing that means the basic stereo with the 6 speaker set up. Probably the same wiring diagram with a speaker added to the left and right front. Gonna have to get in there and start testing stuff.

The UQ1 & UQ3 codes defined below.
UQ1 76 88 RADIO,STEREO INSTL PROVISIONS
UQ3 26526 P SPR M SPEAKER SYSTEM PERFORMANCE ENHANCED AUDIO

 

[Amanda Hugenkiss]

If you determine it is the head unit, radios of that vintage many times were modules that plugged into the faceplate. The top module is the radio portion and the bottom was the cassette portion. You can easily swap it out with a junkyard module, there are tons of them. Find a GM car in the yard that is newer. Buying one of these modules online is hundred$ but a junkyard one may be $30-50

 

[G67RMS]

If you determine it is the head unit, radios of that vintage many times were modules that plugged into the faceplate. The top module is the radio portion and the bottom was the cassette portion. You can easily swap it out with a junkyard module, there are tons of them. Find a GM car in the yard that is newer. Buying one of these modules online is hundred$ but a junkyard one may be $30-50

That’s a great idea, thanks for that info.

 

[G67RMS]

So just an update on this. I replaced the head unit with a GM one of similar vintage, I think it was from a Chevy. Now had some sound from the back speakers but still low and somewhat crackly. I assumed the old paper cone rear 6x9’s may have been shot. Put in a pair if new in the box pioneer 6x9’s and now it sounds great. Still no right front sound but I am leaning toward shot speakers more so now. Thanks for the help.