Door Lock problem Ford F-Series

Installed an alarm last year in a 2000 F-Series Truck that has 4 doors/power locks.   The door lock wires were (-) pulse for lock & unlock.  Customer said a couple months ago, the power door locks stopped working.  I recently checked it out and alarm was outputing correctly but the doors would not lock or unlock.  You could here the sound like the solenoids were engaging,  but no physical locking or unlocking.   Even the switch to lock/unlock all doors didn't work.  The sound was there in each door but it was as if the solenoids were not getting enough power or current to mechanically lock or unlock.    I don't think this is Alarm related, but has anyone else experience something like this or have an idea of what the problem may be?

Check to see if you can manually add a ( - ) pulse to the target wire and get the actuators to engage. So you said that the alarm does output a clean ( - ) pulse to the door locks ?

I measured the negative pulse for both lock & unlock with a digital meter and it was o.k.   As I said,  the lock are not even working with the factory lock/unlock switch.   It's almost though all the factory actuators/solenoids are "fried" but they still make the noise but don't seem to have the torque to mechanically lock or unlock. 

I just don't want the customer to think the problem is because of the alarm or a result of the alarm being hooked up to the door locks when the alarm is fine.

When  you did the install did the solenoids felt like they were about to give?  I asked this because  the solenoids start making noises when there about to go out.  You might check the switches to see if they are fuctional OR

• Check your relays if they were reverse polarity
• Check your connections, if you tagged pink / YELLOW for lock and pink green for unlock you did it right.
• The only other problem i could think of is that its a FORD

• The only other problem i could think of is that its a FORD

I think that is it!  Being that it's a Ford,  that is a problem within itself !!

I told the customer to have the dealer check out the problem cause all my connections looked fine.  And since the D/L switch on the Driver AND passenger side both Audibly control the solenoids,  I know both switches can't be bad.