keyless entry problem

[commandoNate]

My 95 850 is having the following problem. When I hit the unlock button everything unlocks except the tailgate. When I try to lock it from the remote nothing happens. If I unlock the tailgate with the key (so all 5 doors are now unlocked) the lock button works. To make it even stranger, it only seems to do this when the temp is below about 40 degrees. If it is warm everything works as it is supposed to. Any suggestions?

[Ozark Lee]

Welcome to MVS commandoNate,

The tailgate lock is critical to the central locking system. There are a couple of common failure points. First is the wiring harness as it goes into the tailgate. It is not uncommon for the wires to fatigue and break at the point where they bend as the tailgate is lifted and closed. They are buried in the wire loom and the insulation normally remains intact which would account for the thermal characteristics of the problem. The colder it gets the more the wires try to shrink and they pull themselves from just touching to not touching at all.

Once you find the problem it is easily fixed by simply splicing the wires back together.

There is a full set of schematics - plus a lot more - in the factory service manual which can be downloaded here:

http://www.savefile.com/files/2001813

It is a new link and it is kinda spammy but it is well worth it.

Another problem can be the microswitch that is built into the lock. It is one assembly and it normally requires that the lock mechanism be changed to correct it. New they are stupid expensive so that is the kind of thing I would search the junk yards and eBay for.

...Lee