Cadillac Owners Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
2,721 Posts
Discussion Starter #1
You know how the car unlocks the doors when you shift into Park?

It sometimes doesn't unlock the doors these days.

I'd say 1 out of 20 times it shifts from D to P, it forgets to unlock the doors.

Is there a switch going bad or something?
 

·
Registered
Joined
·
5 Posts
powerglide said:
You know how the car unlocks the doors when you shift into Park?

It sometimes doesn't unlock the doors these days.

I'd say 1 out of 20 times it shifts from D to P, it forgets to unlock the doors.

Is there a switch going bad or something?
I don't know the answer but I have the same problem with my 95 Deville, and I have had the same intermittant problem with the auto lock/unlock with my 93 Coup deVille and even with my previous '86 Fleetwood (which was only 3 yrs new at that time but high milage) So I 'd say its pretty much a character trait /flaw. Probably the same part stock all these yrs.LOL If some one on this forum knows a fix they'll probably jump in pretty soon, otherwise I don't let it bother me anymore, as long as I can open the doors.
 

·
Registered
Joined
·
25 Posts
i have the same prob with my 86 cadi... LMAO i press unlock and my passenger door wont unlock all the time... Cadillac needs to address the lock problem :p
 

·
Registered
Joined
·
2,721 Posts
Discussion Starter #5
Yeah lucklily the powerdoor lock open.close button works fine for me, so I doesn't bother me too much.....its w=only when I throw it in park, reachf ro the door and find it locked that its a little distracting

I'm sure its a cheap little switch somewhere perhaps in the column.....anyone? anyone?
 

·
Registered
Joined
·
268 Posts
This is controlled by the BCM (and depending on year) may have some tie-in with the RKE module as well. I believe it is determined by the transmission position switch (Park is unlock, all others gears trigger a lock signal) and then sent by the BCM to trigger the doors to lock or unlock. There may also be a relay involved, I've never looked too closely at how this system works since mine has not been a problem (yet...) but it could be a bad relay, or a failure of the trans position sensor or BCM to trigger the proper signal to the door locks. I would not suspect a problem in the column, unless there is a bad part in the column shifter assembly - and that would probably cause other issues such as improper registration of the gear indicator or difficult shifts.

If only one door is affected then suspect the power lock assembly on that door, these are known to get sluggish with age. Also on 97 and up cars, this feature is selectable in the driver option programming thru the DIC. It may be turned off althogether based on how it is configured.

A peek at a FSM would give structured troubleshooting to track this one down. Of course it will vary somewhat from year to year and model to model.

KDirk
 

·
Registered
Joined
·
2,721 Posts
Discussion Starter #7
Thanks Kdrik!

Mines a 98 and I know you can program it to do the auto door thing or not, I think its set to open it because its works 97% of the time. And when it does fail it fails on all doors so i don't think its just a local switch failure.

If someone knows a simple check/fix lemme know!

Thanks
 

·
Registered
Joined
·
268 Posts
It just occured to me, I think that that you have the option of setting it for drivers door unlock only (others remain locked), or all doors unlock when placed in park. Not sure, since I don't have this option on mine but I seem to remember this on my brother's 99 SDV.

KDirk
 

·
Registered
Joined
·
61 Posts
Document ID# 316876
1998 Cadillac DeVille


--------------------------------------------------------------------------------

Power Door Locks Circuit Description
Locking
Setting a power door lock switch to the LOCK position provides an input signal to the body control module (PZM) on one of the following circuits:

CKT 780 (RED/BLK)
CKT 244 (LT BLU)
The switch grounds a terminal on the PZM through the following circuits:

CKT 51 (BLK/WHT)
CKT 151 (BLK/WHT)
The PZM provides an output on CKT 195 (LT BLU). This condition grounds the lock coil of the power door lock relay. With voltage applied to the lock coil, the power door lock relay energizes. This condition provides power from the CONVENIENCE fuse to the door lock actuators through the closed relay contacts and CKT 295 (GRY). The door lock actuators lock the doors because they are grounded. The right front and the rear (on the four-door models) door lock actuators are grounded at G401 through the following components:

CKT 294 (TAN)
CKT 1250 (BLK)
The UNLOCK relay contacts
The left front door lock actuator is grounded at G401 through the following components:

CKT 694 (TAN)
CKT 1250 (BLK)
The left front door UNLOCK relay
Unlocking
The unlocking operation is similar to the locking operation except that the polarity of the voltage applied to the door lock actuators is reversed. The completed circuit causes the actuators to run in the opposite direction, which unlocks the doors.

Setting a front door lock switch to the UNLOCK position provides an input signal to the PZM on the following circuits:

CKT 781 (ORN/BLK)
CKT 245 (DK BLU)
The switch grounds a terminal on the PZM to ground the following circuits:

CKT 151 (BLK/WHT)
CKT 51 (BLK/WHT)
The PZM provides two output signals that accomplish the unlocking function.

On one circuit, the PZM provides an output on CKT 194 (WHT) that grounds the unlock coil of the power door lock relay. The unlock relay contacts close, providing power from the CONVENIENCE fuse to the right front and the rear (on the four-door models) door lock actuators through the closed relay contacts and CKT 294 (TAN).

The voltage to unlock the left front door lock actuator is applied through the left front door unlock relay. When unlocking, the PZM provides an output on CKT 1391 (LT GRN) that grounds the coil of the left front door unlock relay. Voltage on CKT 2040 (ORN) energizes the relay coil. The CONVENIENCE fuse supplies the power to the front door lock actuator through the following components:

CKT 2040 (ORN)
The closed relay contacts
CKT 694 (TAN)
All of the door lock actuators run because the actuators are grounded through the following components:

CKT 295 (GRY)
The lock relay contacts of the door lock relay
CKT 1250 (BLK)
Central Door Unlocking
The left front door and right front door lock cylinder switch provides an input to the PZM. This input is CKT 262 (LT GRN) for the left front door. The input is CKT 265 (LT GRN) for the right front door. The PZM uses these inputs in order to control the central door unlock feature.

Anti-Lockout
The PZM disables the power door locks under the following conditions:

The PZM receives a key in the ignition input signal.
The PZM receives a left front door open input signal.
In order to override the anti-lockout feature, hold the power door lock switch in the lock position for 3 seconds or more.

Door Lock/Unlock Functions
The PZM locks and unlocks all of the doors by the following methods:

Door lock/unlock switch activation
Pressing the door lock or unlock switch on the remote function actuator
Auto door lock function enabled
Central door unlocking enabled
Programming Automatic Door Locks
The vehicle's ignition must be in RUN. To begin programming, press and hold the SKIP INFO and NO INFO RESET buttons at the same time in order to display the following prompts:

DOORS LOCK IN GEAR: All doors automatically lock when shifted out of PARK (P). No automatic door unlock.
DRIVR UNLOCK IN PARK: All doors automatically lock when shifted out of PARK (P). Only the driver's door automatically unlocks when shifted into PARK (P).
DRIVR UNLOCK KEY OFF: All doors automatically lock when shifted out of PARK (P). Only the driver's door automatically unlocks when the ignition key is turned to OFF.
DOORS UNLOCK IN PARK: All doors automatically lock when shifted out of PARK (P) and unlock when shifting into PARK (P). DOORS UNLOCK KEY OFF: All doors automatically lock when shifted out of PARK (P). All doors automatically unlock when the ignition key is turned to OFF.
A YES or NO response must be made after each prompt is displayed in order to continue on to the next prompt or personalization feature. Press the YES TRIP RESET button to choose yes, press the NO INFO RESET button to choose no or press the SKIP INFO button to skip to the next personalization feature.

FEATURE ON appears when a yes response is made and FEATURE OFF appears with a no response.

If a no response is made after the DOORS LOCK IN GEAR prompt is displayed, FEATURE OFF will appear. The automatic door locking system has been disabled and no other door lock messages will be displayed. LIGHTS FLSH AT UNLOCK, which is the next available personalization feature to display, will appear next.

If a yes response is made after the DOORS LOCK IN GEAR prompt is displayed, FEATURE ON appears. The automatic door locking system is enabled and allows the DRIVR UNLOCK IN PARK prompt to appear. Choosing this prompt advances you to LGHTS FLSH AT UNLOCK whereas a no response will display the DRIVR UNLOCK KEY OFF prompt.

If DRIVR UNLOCK KEY OFF is chosen, FEATURE ON appears. Advance to the LGHTS FLSH AT UNLOCK prompt. FEATURE OFF appears as well as the next prompt- DOORS UNLOCK IN PARK if this prompt isn't chosen. FEATURE ON appears if this prompt is chosen. If a no response was made, DOORS UNLOCK KEY OFF will appear. At this point, a yes or no response automatically brings up the LGHTS FLSH AT UNLOCK feature.
 
1 - 10 of 10 Posts
About this Discussion
9 Replies
5 Participants
powerglide
Top