with the hood open stand in front of the engine look toward the backleft it is usually under the intake manifold use a flash light you will see it better
The power steering reservoir is underneath the alternator by the firewall.
Where do you add power steering fluid on a 2003 Pontiac Bonneville?
The cap is located on the power steering reservoir. If you have a 3800 V6 then the pump is located on the rear passenger side of the engine. It is difficult to see the reservoir. Remember the power steering pump is driven by the crankshaft pulley so the serpantine belt drives it. Find the pump and you can find the reservoir.
Inside the power steering reservoir
The Pontiac Bonneville used the same power steering fluid from 1992 until 2005. You should look for GM Power Steering Fluid with part number1050017 for quart sizes or part number 1052884 for pint sizes.
At the power steering pump reservoir. The power steering pump or reservoir is located on the left side of the engine between the engine and the firewall
It is on the left side of the engine back by the firewall.
To locate the power steering reservoir, please watch this video in youtube by YMSCanadian: http://www.youtube.com/watch?v=quU4QiXTUx0
This is two of the things I know that could be wrong. The power steering pump is either bad or there is no power steering fluid in the pump causing it to have steering problems. Be sure to check the fluid level in the power steering pump.
In my Montana, if you are facing the car in the front, the power steering reservoir is on the left top of the engine. To the right of the washer fluid reservoir. It was tricky to find because some wiring was going over the top of it.
Behind the strut support bar, behind and under the alternator is the power steering cap. It is difficult to get to. Good luck!
I found instuctions at autozone.com, and at my library in Chiltons in the reference section.