1995 Grand Cherokee - Power door locks unlock but not lock - the lock button on both doors doesn't work - all fuses good - maybe it's a bad relay-where are they located and what else could be wrong?

Answer 1

it is probably the butons. mine are temermental if they get a little wet the will work one way and not another. if you take the door panel off you may notice that a wire or two fell off. mabey mabey not. good luck. iam going to just get new stiches soon.

It was not the buttons. I found the problem, and NOONE else knew of this particular problem, so I'm posting my findings:

The doors unlock ok. The refuse to lock from either door's buttons.

The door actuators, wiring to the doors, switches, and relays all work fine. This was a different, less common wiring/electrical problem.

It's not a wire issue in the door, as I traced the wires to their relays under the glove box. The relays are fine.

Here are the diagnostics so far:

a. The relays DO get the 12v signal from the lock button on both doors

b. if I manually trigger the relay with 12v and ground, all the doors both unlock and lock

c. One of the wires connected to the coil of the relay, colored yellow with black stripe, should be connected to ground for the circuitry to work properly, but it does not have a connection to ground (discovered by using an ohmmeter), so the relay never triggers. If i connect the wire directly to ground, everything works. However, it appears this Yel/blk wire isn't meant to go directly to ground, as it travels under the dash, over to the center console, and there I loose it.

I then found where the wire from c above went:

To the chime module. The chime module is connected to signals from the ignition, lights, etc., and is made with a ground inhibitor. Basically the ground inhibitor activates whenever you leave the keys in the ignition or the lights on, and that causes the door-locks to be unable to lock. My chime module contacts were dirty. I removed the module, reinstalled it, and presto! Now the doors unlock AND lock! If that also doesn't work, the chime module could be bad if you have symptoms as I described above.

So the solution was: clean the contacts on, or replace, the chime module. The chime module is red and located under the far left of the dash. You can see and access it without removing any of the dash.

KyferEz