How do I reset my 601R refridge so the suction seal comes on?

I assume your unit is cooling correctly since the following explanation is predicated on a properly working refrigerator.

There is no "suction seal" that comes on with your refrigerator, rather this the effect from the closing of the door and the rapid cooling of the warmer air (that entered with the door open) which causes a contraction that is the vacuum you feel. This will only last for a short time as the built-in venting (usually via the drain) will allow the low pressure to balance so the door opens normally. If this has ceased to occur it indicates there is an air leak somewhere which prevents the vacuum from forming. Replacing door gaskets can be tricky so be certain the door closes and seals all the way around. Using a dollar bill (or similar slip of paper), insert the bill between the door and cabinet, close the door on it and then gently pull the bill out. You should feel a slight resistance and have to tug to slide the bill out. Repeat this every few inches all the way around the door to locate any spots where the contact is not as firm. Typically this can happen on the hinge side, especially near the corners.

You might have a hinge problem, a warped door or some other problem that keeps the door from closing fully.