I have a 2000 Bonneville ssei
The power windows ,door locks power mirrors and radiator cooling fans all quite working?
any help would be great.
Vic

ddalder has been working on some stuff to cover this area. I'm sure he will be on soon.

Did all these things quit at exactly the same time? There is some commonality between the mirrors, windows and power door locks, but these really have nothing in common with the engine cooling fans.

When you say all the windows quit, is this only when you try to open/close them from the driver door controls? Can you use the control on each individual door and have the other three windows function? Will the door lock switch on the front passenger door lock and unlock all the doors? Do you have a remote key fob and if so, does it work?

Does the backlighting work on the driver door switch panel and the seat memory buttons?

What leads you to believe the cooling fans quit? Are you noticing any overheating, additional symptoms will be helpful.

Yes they all quite at once first it was intermittent but now constant. all doors and locks do not work key less remote I can here a relay click but locks will not work. seat memory quite also. As for the fan the car got hot the other day and I opened the hood and nether fan was running The car got hot enough that the trans started shifting weird (hard shift) I am going to check the ground buse under the carpet by the front doors.
thanks
Vic

Also the fuel gauge is acting up and the oil pressure gauge always reads 120 but I don't think these are related
Thanks
Vic

What does the instrument cluster show for battery voltage while the car is both running and not running with the ignition on?

Do you have wiring diagrams for the car?

Your problems are wide spread enough that I'm not convinced your problem is a bad ground (unless it'* where the battery cable bolts to the body). Have you thoroughly checked your battery cables for corrosion. Often these can "look" okay, but pulling back the boots has frequently revealed problems. I think in this case, this should really be your first check.

Here'* the problem... Each door has its own door control module to manage all functions within their respective doors. All door control modules communicate using a data bus. The problem with the "ground" theory is that each of these door modules all ground at different locations in the vehicle. For all doors to quit at once would be so extremely coincidental that I can't even imagine the math to figure out the probability. Additionally, you have other issues going on and again, these componenents also ground in different locations. What you're describing sounds more like a general "voltage supply" problem than an individual component or module ground point.

It is very common for people to jump on a "bad ground" with these cars, but this is seldom the case in the 2K+ generation. Not so uncommon in pre-2K however. Grounds in the newer cars are a better design and located in places to avoid the moisture that plagued pre-2K cars ground busses.

The battery show 13.4 and 14.4 and running. The connections on the battery are fine. I don't think it would be the main ground as the car starts good and the power seats still work along with radio and lights wipers. but I forgot the wind shield washer quite also at the same time.
Vic

I'm going to need some time to look through diagrams. What you're describing is somewhat unusual because of the number of different systems involved. Since it cranks and starts without a problem, the power seats all work and you appear to have good battery voltage, it does seem less likely to be a battery cable connection problem.

Have there been any modifications to the car (new stereo, remote starter, etc)?

I'm assuming you've checked all the fuses? It would also be very interesting to know the results of a diagnostic scan. Many auto part stores can do this for you, but the non-Tech 2 scanners do have limited functionality and may not reveal all information stored.

If you want to test your negative battery cable just to get that out of the way. I actually just made this write up today because it'* a problem that pops up a lot. Totally easy to do with a friend helping.

https://www.gmforum.com/t279492/

The car is all stock. I do not have a wiring diagram if you know where I could get one that would be great
Vic