: Problem with Radio in 2005 STS



mikemillion2000
12-03-11, 03:16 PM
Hello, I know you've folks probably heard this one before, but here goes:

I just changed the battery in my 2005 STS. Noted shortly before I swapped it out, the radio/display went dead. I did a search and found out that there is a fuse box in the rear right seat that has the fuse for the radio (I checked and it looks fine, no breaks), I checked the fuse box in the rear left seat that has the fuse for the amp( it looks like a relay, but it still looked fine)..

Any other things I can check before I take out a loan and take the car to the local Cadillac dealer?

Thanx a million.

Mikemillion-

scott9001
12-03-11, 03:54 PM
probably in a security mode did u keep power on the system when you changed the battery?

mikemillion2000
12-03-11, 04:16 PM
That would be a no. The car was off when I swapped it out. I start the car, drove it, brought it back to the house just fine, just no radio/display.

carter's_sts
12-03-11, 10:39 PM
I changed the battery on mine 2 weeks ago and did not keep power on the system. Did not have this problem. Probably had no power for about 5 minutes.

ddalder
12-04-11, 12:00 AM
Not likely a security feature. Part of the VIN is stored in an EEPROM (Electrically Eraseable Programmable Read Only Memory) within the radio when it is configured for the first time. When it powers up, it will read the VIN from the data bus and compare with what is stored. If there is a discrepancy it will display a message. Having the radio disconnected for a long period of time will not affect security features in newer radios. Is this a base radio, or does it have navigation? Does any of the backlighting work when your headlamps are on?

mikemillion2000
12-04-11, 08:30 AM
Yes, it is a base radio, I've made no mods to the car since I've had it.. Has navigation and all.. And yes, the backlighting (if you mean the lighting inside the car in the rear?) is working just fine.

Angus Young
12-04-11, 08:43 AM
I have this same issue, I would have to disconnect then reconnect the battery in order for my display to come back on, sometimes the radio stays on for weeks at a time, then sometimes it wont even stay on for a day, This is such a frequent thing now I have caught a message that says communication fault, No XM signal, then goes blank dead, SOMETIMES if you press the eject button for 6 seconds the screen will move back and forth and eject the nav disk the display will come back on and the radio will be on FM. I noted this, around the same time the radio started acting up, If I floor the car or get on it hard a very strong burning smell fills the inside on the car, this doesnt seem to affect radio but just bringing it up.... and mine is a 2005 STS 1SG with Nav and a lockpick also there is no backlighting when its not working, screen is totally dead, but will move back and forth if you eject the disk.

KRSTS
12-04-11, 09:16 AM
Yes, it is a base radio, I've made no mods to the car since I've had it.. Has navigation and all.. And yes, the backlighting (if you mean the lighting inside the car in the rear?) is working just fine.

Yea that backlighting is controlled bvy the flux capacitor:hmm:

ddalder
12-04-11, 11:19 AM
Yes, it is a base radio, I've made no mods to the car since I've had it.. Has navigation and all.. And yes, the backlighting (if you mean the lighting inside the car in the rear?) is working just fine.
The base radio would be the AM/FM/CD whereas the navigation radio is an uplevel radio.

As for the backlighting, what I'm referring to is the illumination of the buttons on the radio when the headlamps are on. If I'm not mistaken, with the radios in the STS, the backlighting is controlled by a data signal as opposed to a variable voltage signal supplied to the radio. If the button backlighting works, this would suggest there is power to the radio and it does have some degree of functionality. Of course for those who don't understand how it works, I can understand the confusion with how the flux capacitor is integrated.

Being a navigation radio, if the problem was a security lock, it would definitely say "Theft Lock" on the screen.

Subsailor613
12-04-11, 02:58 PM
Replaced my battery this last summer, Took it out and took it to the parts store,
Non-NAV.It was out for over an hour, replaced bettery, No ill effects whatsoever.
Have Fun. :cool2::cool2::cool2:

dkozloski
12-04-11, 04:09 PM
Disconnect the leads from the battery for a few minutes, touch then together, and reconnect. This will reboot the system and may cure a lot of problems.

mikemillion2000
12-04-11, 06:00 PM
ddalder - I wanted to confirm that the backlighting is functioning, just came in from checking it.

dkozlowski- I tried what you indicated, no dice.. Backlighting is working, but radio/display is still not coming on..

Angus Young
12-05-11, 06:17 AM
Press and hold the eject button, see if it will eject the disk, if not there is no power to the unit, when my display is out I can still eject the disks, also look at the XM module in the trunk, under the carpet on the passengers side and verify the cables are fully plugged in, Sometimes Mine says loss of communication No XM signal right before mine goes dead .

mikemillion2000
12-05-11, 08:20 PM
Angus - Yep, no power to the radio. Though the backlighting is working fine, I pressed the eject and held it for more than ten seconds, no dice, er.. no response from the radio.

ddalder
12-05-11, 11:05 PM
Press and hold the eject button, see if it will eject the disk, if not there is no power to the unit, when my display is out I can still eject the disks, also look at the XM module in the trunk, under the carpet on the passengers side and verify the cables are fully plugged in, Sometimes Mine says loss of communication No XM signal right before mine goes dead .
I suspect this is just part of whatever else is failing in your radio. The radio will function whether the SDAR module is connected or not.

Just because one of these radios won't eject discs doesn't mean there is no power to the radio. Since button backlighting is working, the radio does have power. GM's factory service manual confirms this and is quite clear that backlighting is controlled using the GMLAN bus. Voltage is not supplied to the backlighting by the same method used in several of the other switches and controls in the car, or in the manner used in many other GM models. Because the backlighting works, it also confirms that the electronics internal to the radio works (to some extent) or it would not process the lamp on/off/dimming signal from the data bus.

mikemillion2000 - At this point it seems like an internal failure. You have a couple of options...

1. Take it to your dealer, have them scan it and see if there are any radio codes. GM will have to send it to one of the authorized service centres for repair as this is not a dealership level repair.

2. Consider finding a used radio on eBay. There are a lot available for your year. You will need to take it to your dealer to be unlocked and reconfigured for your car. This may still be well less than you'd pay to have yours repaired. The advantage to having yours repaired is you will have some degree of warranty.

There is an outside chance that connector C3 (on the back of the radio), terminal 1 or 9 may not be making good contact. This isn't very likely though. Alternatively, it is possible that wiring from C201 terminal 26 is problematic. Again, not likely.

jsteve2
01-15-12, 01:29 PM
'06, STS. New battery. Problems started after left motor mount was replaced. Radio is on when car started up then display went off. Phone ok, screen for navigation ok. Could not get AM/FM/XM bands to display??!

EChas3
01-15-12, 05:26 PM
Try pulling the radio fuse & then replacing it.

If that doesn't work, pull the negative battery terminal & the postive termial, touch them together briefly and then reconnect positve, then negative. This provides the best reset and and may require re-setting the express-up windows.