My boyfriend has a 1988 Cadillac sedan deville and

Question edited for clarity.
Question moved to model category.

There is on one generic Cadillac video on this. It is a very old model.

https://www.google.com/search?q=1988+Cadillac+Deville+Sedan+replace+power+steering+pump

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check on the steering rack for a electrical switch ?? hold it a 1988 model ?? with a manual pump??

If the lights stay on for more than 30 seconds after the engine and switch are turned off then it may be time to have the diagnostic check. Many auto parts chain stores will do this for free and tell you what needs replaced as they want to sell you the parts required.

It is the engine front cover( from diagram in the 1988 service manual

adjust the vacuum switch on top of the steering column under the dash

Better start with the controller if it is malfunctioning. If it is the all elctronic one, may not be sending signal to turn on compressor.

Sounds like the battery is weak or the alternator isn't providing enough amps to keep the engine running and power the lights at the same time.

The mechanism in the steering column works you turn signal and brake lights. Odds are its bad, they break sometimes because of the tilt wheel and sometimes they just wear out. You have an air bag in your wheel, I would suggest you might want to take it to a shop. lee


Please vote if this was helpful or not

Replace tank sending unit an the trunk pull down switch. See gm dealer for diagrams!