Perhaps the suspension air bags in the back have become dry rotted? (cracked and deteriated) therefore the air pump stays on trying to fill them even though they are leaking? It's a common problem with cars that have suspension air bags. They can be expensive to replace yet there are cheaper, aftermarket, kits out there on the internet.
http://www.sjdiscounttools.com/bragmw594.html this is needed to pull the cart,s and to reinstall them.
1995 Buick riviera is not equipped with "air ride" type suspension. It is, however equipped with air shocks and coil springs. The air shocks are filled by a compressor in the rear of the undercarriage just in front of the gas tank. If you have an air leak, replacement of the air shocks and/or line kit may be in order.
I had the same problem on my 95 Riviera. I bought a set of air shocks from Autozone and installed them putting the air pressure valve in the trunk out of the way and disconnected the auto system under the car. Now I added some air to the air shocks and it is adjustable by releasing the amount of air according to the ride you like. worked perfectly, and no more pump running constantly. $70.00 for air shocks verses $400.00 for factory pump and original shocks. works great.
A 1995 Buick Riviera wiring diagram can be obtained from most Buick dealerships. The wiring diagram can also be found at most auto-parts stores.
Behind the glove compartment
Under the back seat!
push button
6 injectors
When it reaches 25 years of age in 2020.
it is between 35 and 47
why is my 1995 buick roadmaster running hot
ON THE 1995 Buick RIVIERA THE HORN IS LOCATED UNDER THE LEFT HAND SIDE FENDER. U WILL HAVE TO TAKE OFF THE TIRE AND REMOVE THE FENDER PANEL. THE HORN WILL BE ON THE RIGHT SIDE OF THE LEFT INNER FENDER.