The grease in FMJ door latches, Chrysler used 30-40 years ago, will get rock hard over time. For 95-98% of us with lazy or inoperative power door locks, the best option I know of is to remove the latches from the doors (all of them, not just the ones acting up), give the latches a good cleaning (a gasket scraper helps) and apply a generous amount of grease, as deep onto the latch as you can get. You will be good for another 30+ years.
The door lock actuators (simple electrical solenoids) does a decent job and they do not fail that often – but when the grease hardens, they just doesn’t have the oomph needed to lock or unlock.
The door latches are the same if power or manual door locks, but are different for Left vs. Right, as well as Front vs. Rear.
I recommend working on one door at a time. The #3 Phillips screws are not easy to remove – so using an impact screwdriver does help.
When re-installing the door latches, I recommend getting one screw finger-tight to get latch into position, then add a small drop of Loc-tite blue to the threads of other two screws. Once the other 2 screws are in and tight, then remove the first screw and do the same. The screws do need to be tight, but not excessively tight. The Loc-tite will keep them tight.
Those door latch screws are important to keep tight and causes all kinds of problems if they loosen.
After door latches have been re-greased, I also recommend adjusting the door handle (part of latch install) and door latch post (the gold appearing item attached to body), next. The door post will loosen with appropriate wrench and has room for adjustment up/down and in/out.
Afterwards, your doors should open/close with ease and door locks will function as designed.
There are plastic clips that attach the door latch to the metal lock rods and a metal clip that attaches to door lock solenoid to one of the metal rods.
To disengage the clip, I like to take a stubby flat screwdriver and insert at location indicated by red arrow and the rod, and clip rotates away. Then pull the rod out. The clip typically stays with the latch – but can fall out (so watch out).
There can be four different plastic clips used: Left and Right as well as two different size (diameter) rods – each with its own color (see picture, above).
These plastic clips can be obtained at part stores if yours is missing or broken (replace by matching the clip color).
If you do happen to have a defective door lock actuator (or solenoid, the term is interchangeable), the actuators (for the most part) “appear” to interchange with most Chrysler vehicles made from mid-60’s to about 1990 – but some do/some do not interchange. There is a Left and a Right-side bracket attachment for the solenoid/actuator for the ’76-85 solenoids – so a Left M-body, might the same for a Right B-body or pickup – so look at the attachment bracket before assuming the one you have your eye on, actually fits.
The ’86-89 M-body uses one-part number to fit either door. Also, this style fits all front wheel drive cars made in the ‘80’s, as well. Also, If I remember correctly, the ’86-89 version is pop-riveted in. To remove, get a ¼” drill bit and a small punch. Use punch and hammer to knock the metal center rivet pin out, then drill the rivet out (not hard to do). Use a ¼” diameter, ¾” long (or ½” long) bolt/nut and go back together with (two each, per side).
The older FMJ’s uses two small bolts to attach solenoid in place.
This is part number 3861748 (or 3861749, depending on side). These fit ’76-85 FMJ’s. It also fit ’77 B-bodies – so ’75-81 B/R-bodies might be a possibility. They might also fit other bodies, as well.
The ’86-89 M body uses 4396015 – which got superseded to 4467252.
I couldn’t find a picture online, but part looks identical, except the threaded nuts are missing.
This is some actuators that are not a direct fit. I was just using them for example that you need to pay attention when looking for one. If desperate, a person could make these fit . . .
The electrical connector is different. This one "might" fit with wiring pigtail change (maybe).
These are from a C-body. Notice the shape/angle of bracket.
BudW
