Ikeep losing functions on my Cadillac STS 2005 only after winter storage. I lost interior entry lights, climate control and outside temperature gauge all at the same time. Now I also lost my clock.

Yes, the external battery was dead enough so that the car would not start, but the internal battery that cadillacs have still allowed security and horn and other functions to still work. I have since then put in a new battery and the functions came back on, but only briefly. As you run the car awhile, the 3 same functions again disappear, and now a new function, the clock has also disappeared. If you remove the negative cable from the new battery for several minutes, the functions again come back, but then disappear after the car warms up. Odd to me that they come and go. Also, while driving the car, the functions come on for a bit and then go off. Could it merely be a bad relay from charging the old battery with a battery charger before I replaced the battery with a new one?

Thx for your answers. Why would these features come on and off though???

Thx for your answers. Why would these features come on and off though??? Should I at least start by switching out some of the relays in the fuse panel with a new one to see if it makes a difference? I know my Cad dealer will charge me $150 just to test this issue.

If you have navigation system in you STS the Not being able to set the clock is a known problem but nobody wants to step up and fix it. Look at the Cadillac forums for additional information.

Had mine in for ECM replacement. dealer did not disconnect battery but when I picked it up the clock was gone and I could not set it. Three days in the shop and several calls with GM technical support the dealer was told there is at this time no fix, except for replacing the entire radio/gps unit. My son did some research and found out that GM is aware of this "glitch" and it is related to an internal software problem. (Y2K hack?) Apparently the clock shuts down after so many hours of actual vehicle run time. My thought was if you replace the unit with a used or even new unit off of the shelf, it will eventually die if it has the bad programming built into it also. Until GM acknowledges the problem and steps up with a fix, I think we are all out of luck.

I am currently having the exact same problem with my 2005 STS V8. Littlepooh, any confirmed fix?

Electronic control module ECM Very expensive from dealer. I bought mine online.

The last thing that I heard for 2005 Cadillac STS is that the clock should come back around August 20th, 2020. I have no further information or explanations as to why this date will fix the clock. I bought a wristwatch for $25