Why wont 1997 cadillace stay running - 1997 Cadillac DeVille

If it wont crank over the battery might be to weak to start the car but just have enoughf juice to run the electronics in the car.
Or the starter died.
1st charge the battery up and see if that works.
2nd if the fully charged battery dosent solve the problem then replace the starter.

It only takes one bulb to blow, that side wont blink, it will stay on, blinker lights have amber lens or amber globes if you have clear lens.

Check the light green wire going to the HVAC controller. With key in RUN position, you should see battery voltage. Wiggle the wire and see if it stays. If you lose it, you've got an open in the harness.

No,it is not,the temp should stay about 200 to 212,if the cooling fans are staying on,and not going off,then the cooling system has a problem,change the thermostat,and bleed the air from the cooling system.if this does not help,change the coolant sensor out with a new one.

I would try running some fuel tests to see if pump is working.

If it's like my 1990 cadillac deville, get pliers and pull up on the window while pushing the switch up for the window. There could be a bad motor. How much? I don't know. It will vary from shop to shop.

We all need help sometime.

PO135 is oxygen sensor Bank1 sensor1. PO404 is EGR.
personally, I'd pull EGR off, clean pintle good with throttle body cleaner or carb cleaner, re-install, erase codes & try it for a while & see if it code(s) come back.

check to make sure the twilights are off.

IAC motor

its your fuel pump hade the same problem