Window wont roll down, speedometer stays at 0mph, lights wont come on inside car, and transmission started slipping. whats wrong with my car

lost speedometer, what does that mean 0mph at 50? ??????
YES, CHECK all fuses first. all cars, for any electric issues.

A./c lost, (ok there are 6 things that cut A/c some are normal)
one is HVAC dash blower fan must blow or AC brain cuts A.C
this prevent ICE up. (normal)
please:
why guess? please stop guessing and throwing parts and cash.
what does lost all power, driving mean.???
lost engine power (cant drive)
or lost all electric power (a prime reason for EFI to die , for lack of 12vdc electric power)
does lights die on the car, at the moment of problems?
Dash cluster , head lights, any lights.
does engine STALL? (0 RPM is stall) 300 RPM is bad idle.
800 RPM is normal hot idle, never less.

if this is just and engine power issue, (cant drive at all ,or only slow or
slow up hills?)O
my car will not move fast,? in any gear? and transmission don't slip
and no DTC scan codes (checked and smart to do first)

I'd be all over fuel pressure. this is a $20 gauge , that must be connected to the fuel rail to read pressure.
28psi is minimum for all cars.
if i knew what engine was in your car, id look yours up
alldata.com has this info.

the ecu can not report wrong fuel pressure, it cant
so is always and issue, with total engine power loss.
so is skipping 60,000 mile FULL TUNEUP's

if you need those charts they are easy to get. for any car.

tell more get more.... regards

speed sensors are easy to change and can be done in about 15 minutes by any mechanic. if that doesn't take care of it you might need an instrument cluster. they will run about $300 and take about 30 minutes to change. you will have to special order the cluster because the mileage has to be programmed at the factory

It sounds like you have a ground issue near the transmission. Make sure the ground strap above the upper radiator hose is booked down good. Also check the plugs on the transmission for a loose connection.

no it is internal clutches inside the transmission

The speedometer cable may have broke or rattled loose.

Replace the speed sensor located on the transmission this sends the signal to the speedometer, you may want to check the plug and its terminals to be sure the terminals in the plug are not corroded if they are clean the terminals with electrical contact cleaner then drive the care see if cleaning the plug fixed it if not replace the speed sensor.

I suspecft this is a security programming situation. I have something similar going on with my '95. I have to get an owners manual to find the sequences. I stumbled into this by manually locking the front door and turning on the key with the door open.
re: the dash lights. I find if I have the interior light dimmer all the way to the right it locks out some things but moving it back to the middle puts it back in operational mode. aside from the flashing, non playing stero. At least I can drive it and powerlock the doors IF the doors are closed.

about the guage, try replacing the cable that goes to the back of the sppedomoter to the transmission

I had the same problem with ABS light and speedometer, I was told that it is the transmission control module. It has not yet stopped shifting but I have had times where it just wont stay running. It will start and then stall. Hope this helps.

I don't believe the problem is in the vehicle speed sensor. I suspect the problem may be the computer. The speed sensor is just a magnet inside the transmission with an induction coil outside to create an electrical signal every time the transmission output shaft turns. That signal goes to the computer and the computer tells the transmission when and how to shift and displays the speed on your electronic display. I would start by having a reputable transmission shop check out the transmission, then take it to a good mechanic to have him check the computer. It is a relatively expensive fix, but with only 70,000 miles on the Caddy, it should be worth it.