* Door Locks Locking Automatically After a Certain Speed: This is the most common "auto-lock" feature. There's usually no way to disable this entirely in a 1998 Voyager *without modification*. Some models might have a fuse you could remove, but this isn't guaranteed and could affect other electrical systems. Your best bet is to check your owner's manual to see if there is a setting or fuse related to this. If not, this is likely a hardwired feature.
* Remote Locking System with Auto-Lock After a Delay: Some Voyagers had remote key fobs with programmable options. Consult your owner's manual; it might explain how to adjust the auto-lock timer or disable the feature through the remote itself (a less common feature for that era).
* Aftermarket Alarm System: If you have an aftermarket alarm system installed, its settings might be controlling the auto-locking behavior. You'll need to consult the alarm system's installation manual or contact a professional installer to disable the auto-lock function within the alarm system's programming.
In summary: Your chances of completely disabling the automatic door locking feature without professional assistance are slim. Your owner's manual is your first and best resource. If it doesn't provide a solution, you'll likely need to consult a mechanic specializing in older vehicles to explore potential solutions, such as finding and disconnecting the appropriate wire (not recommended unless you're very knowledgeable about automotive electrical systems). Remember that tampering with your vehicle's electrical system incorrectly can cause further problems.
