This has been a torn on my side for a while now. Fought with several suppliers, rebuilders & etc. No one seems to have answers for me. Seems to affect 98+ Sevilles & 2000+ DeVilles.

Problems usually start after replacing the rack n pinion units off the shelf. A lot of the times, the old rack has broken brackets on the passenger's side, so the whole unit has to be exchanged. After that, the steering becomes incredibly stiff. You can go through many rack n pinions with the same stiff symptom!

After searching the manual, archives & internet, no luck on a solution! After changing out racks, power steering pumps, hoses, etc. No answers!

The service manual doesn't give you a lot of information on how magnasteer works, just that the steering gets lighter on low speeds & stiffer on higher speeds. There are codes for malfunctions, but no codes ever pop up on these cars.

All this time, I was assuming the power steering has a certain assist & the magnasteer system creates resistance at higher speeds, but apparently, it's the opposite! Magnasteer assists in low speeds! Don't believe me? Disconnect a properly working unit & you will see that the steering will get stiffer.

So why the stiff steering? It appears rebuilders treat 98+ Sevilles & 2000+ Deville racks as the same units! They look the same, feel the same, but have one very tiny difference. The 2 wires going to the magnasteer unit are backwards! If you switch the wires around, you will create a stiff rack in low speeds! Polarity is critical on the Magnasteer units!

Now, it makes sense. 90% of the Cadillacs out there are DeVilles. About 10% Sevilles, which is a rarer car. Most of the racks on the shelf are from DeVilles! So if you put one of those on a Seville the polarity on the Magnasteer is backwards, making it stiff! I've only had one DeVille so far where the steering was stiff after a rack n pinion replacement & I've had many Sevilles with this problem.

Now, I have an easy fix. Switch the wires on the connector around! Before this solution, I would have the same unit rebuilt & avoid off the shelf units, but that's not always possible.

Hope this helps some one.

Juan from California