1994 E-150 van with power door locks has worked great up until a year ago (I have been putting this off headache...).

Now when you push the alarm (Alpine) button fob to unlock the doors... nothing.

Once you are inside and driver side lock switch (I replace that recently...) the switch will unlock all the doors BUT won't lock the doors!

I had a shop servicing my van awhile back and had them to look at it while my van was there.... and they was stumped too! They even discovered you can use the key to unlock any doors from the outside BUT NOT LOCK any of the doors. Not just 1 door, all of them!

I have bought all new door lock solenoids but I have not torn all the doors apart yet.

Any ideas gurus?

 

I doubt it's the solenoids

 

I did change out the arm rest switch so what else is there?

Any relays?

 

do you know how to use a multimeter ?
If so, check for voltages at switches , and such
if a shop was stumped , they were not a very good shop

 

Yes, I have and know how to use a mulitmeter.

The shop was doing many other repairs and I just asked them if they would look at the lock problem.

The solenoids only have a red and a black wire so when red is hot, they move one way like lock.
When the black is hot, they move in the different direction like unlock...

Over the weekend I replaced the rear cargo door: Latch with all cables (I had tried those alum cable ends but those didn't fix the non opening problem), Solenoid, key lock and the license plate box....now it works like it's supposed to.
Even key locks the door.

A buddy that is an high end auto and home electrician was stumped too but has been thinking about my problem.
He just told me there's relays inside the ds kick panel that the alarm (He installed a long time ago) also connects to and one of those might be bad...