Small motor running ? 89 Olds 98

This small morot (Compressor ?) dude is running about every 10 minutes so I finally unplugged it just to save the battery. Car seems to run fine. It is located at the extreme front left side of the engine compartment directly behind the head light. Looks like a small motor for something. What is it ? Why does it keep running ? Why does having it unplugged not cause trouble ?

It's the compressor for the "ELC" (electronic level control) for the rear air struts. More than likely you have a leak in the system that is causing the air pressure to leak out. Most likely either you need a new line kit or one of the struts is leaking. The systems uses a height sesnor with a link to the right rear lower control arm to sense the height of the rear of the vehicle. It sends a signal to the compressor to turn on to pump up or exhaust pressure from the rear air struts to maintain proper level of the vehicle depending on the load in the rear. You can find the leak with a spray bottle of soapy water. Spray the lines and the strut bladders down and look for the bubbles after you have the system pressurized. Usually you can even hear the leak if you wiggle the lines. I would start at the rear of the system at the struts, they are most likely very rusty and the fitting where the are lines attach to them are most likely rusty under the boots. To remove the boots, turn the little metal clip 90 degress and pull the boot off. Especially inspect the left rear line approx 6 to 12" inches from the fitting for a rub through condition on the line. You can cut out the bad part of the line if it's small enough, and get a brass splice kit ($10-20) at the dealer to repair the line. You may have to re-route the shorter line. This system works good but does require a minimum of like 15 psi pressure maintained at all times. If the car is really rough and you just want regular gas struts (no air assist) you could do that too. I'd be interested in your height sensor and compressor if you decide to go that route. I wouldn't mind having spares.