Aside from the Fuse/Relay boxes in the engine compartment, there are two inside the passenger compartment. One is on each side of the transmission hump in the front foot area.
mine does not have one
I believe they are located on the starter.
Curb weight, 3,309 lbs
The original wheel size is 15"
On a 1990 Buick Riviera, the ignition coil is located on the engine, typically mounted near the front of the engine block or on the intake manifold. It may be somewhat obscured by other components, so accessing it might require removing certain parts for better visibility. If you're looking for the specific location, consulting the vehicle’s service manual can provide detailed guidance.
Regular ethylene glycol antifreeze............
In a 1990 Buick Riviera, the starter is located on the passenger side of the engine, near the transmission bell housing. It is mounted to the lower part of the engine block and can be accessed from underneath the vehicle. To reach it, you may need to remove the protective splash shield or other components for better access.
It uses a distributorless coil pack and a crankshaft trigger sensor.
I just purchased a 1990 Buick Riviera with 45,000 on it for my daughter. However, I did have a brief period that you discribed with the car stalling out. I don't know if this will help, but I just read at another site, that it may have a faulty idle air control.
In the 1990 Buick Riviera, the horn is typically located behind the front grille, mounted on the front of the vehicle. You may need to remove the grille or access it from underneath the car to reach it. It's usually positioned near the front bumper area, making it accessible for repairs or replacements.
1990 lincoln town car
If both sides (right and left) don't blink on and off, the blinker "can" may be the culprit.