C3 1978 Power door locks
Thread Starter
8th Gear
Joined: Apr 2018
Posts: 8
Likes: 1
From: Jonesborough TN
C3 1978 Power door locks
My 78 has new power door lock actuators. If the doors are unlocked, the drivers side lock switch will lock BOTH doors. But that is all that works. The drivers side switch will not unlock either door, and the passenger side switch does nothing. Thoughts? Do I need to replace the wiring harnesses and switches on both sides? I’ve unplugged all the connections and cleaned the pins and connections with a wire brush. Appreciate any others suggestions.
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
My 78 has new power door lock actuators. If the doors are unlocked, the drivers side lock switch will lock BOTH doors. But that is all that works. The drivers side switch will not unlock either door, and the passenger side switch does nothing. Thoughts? Do I need to replace the wiring harnesses and switches on both sides? I’ve unplugged all the connections and cleaned the pins and connections with a wire brush. Appreciate any others suggestions.
If you have replaced the actuators, then you know how to access the lock gear behind the door panel. Check the article out with link below. It shows what to look for when examining the door switch like frayed wires.
Hope this helps!
Power Door Lock Repair
Intermediate
Joined: Jan 2013
Posts: 26
Likes: 0
Power door locks 79 c3
how do the power locks actually work on the 79 C3? Since my locks never worked and l did not know l had power locks until l went to replace lock for new key? Thanks...
My 78 has new power door lock actuators. If the doors are unlocked, the drivers side lock switch will lock BOTH doors. But that is all that works. The drivers side switch will not unlock either door, and the passenger side switch does nothing. Thoughts? Do I need to replace the wiring harnesses and switches on both sides? I’ve unplugged all the connections and cleaned the pins and connections with a wire brush. Appreciate any others suggestions.
Melting Slicks
Joined: Oct 2003
Posts: 2,176
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From: Chapel Hill NC
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I have a very original 82 CE with only 11k on it. The previous owner spent a lot of time and some money attempting to get the power locks to work without success. I spent a lot of time as well. I finally discovered a disconectedted wire connector way up under the drivers side dash. I had to remove an AC duct to reconnect it. I have no idea why it was disconnected but reconnecting it solved my problem.
Are you certain all the connectors are connected?
Are you certain all the connectors are connected?
Instructor
Joined: Aug 2010
Posts: 233
Likes: 18
From: Monrovia Md
Look at the wilcox explanation. The door lock circuit is quite complex, it does not work the way that logic would infer. If either of the switches is not working, neither will work properly.
http://repairs.willcoxcorvette.com/1...atic-and-info/
http://repairs.willcoxcorvette.com/1...atic-and-info/
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
To the previous OP, power door locks are not really that complicated, but you must understand you are working with different technologies to make them work. You have the traditional mechanical linkage (that must be clean and freely moving), electro-magnetic actuators and then the basic electrical feeds.
And as you illustrate, it can be as simple as a single wire disconnect. I found when troubleshooting my 78 power door locks, actuators that had gummed up from moisture exposure, the rubber caps had disintegrated, linkage was constipated from gunk and switch wires had become frayed. Perform some careful inspection and troubleshooting and you'll find your way to the clean air of power door lock functionality. LOL
I have a very original 82 CE with only 11k on it. The previous owner spent a lot of time and some money attempting to get the power locks to work without success. I spent a lot of time as well. I finally discovered a discontented wire connector way up under the driver's side dash. I had to remove an AC duct to reconnect it. I have no idea why it was disconnected but reconnecting it solved my problem.
Are you certain all the connectors are connected?
Are you certain all the connectors are connected?
Last edited by hunt4cleanair; Apr 2, 2019 at 04:59 PM.
Intermediate
Joined: Jan 2013
Posts: 26
Likes: 0
Power door locks 79 c3
how do the power locks actually work on the 79 C3? Since my locks never worked and l did not know l had power locks until l went to replace lock for new key? Thanks...
I appriciat the time and info on the opperation of the door locks. I believe the locking pull tab works an actuator and this locks and unlocks both doors from inside only. I will get on the trouble shooting in my doors where there is no wiggle room to move or work. Thanks again guys >>>>>>>>>>>>>
I appriciat the time and info on the opperation of the door locks. I believe the locking pull tab works an actuator and this locks and unlocks both doors from inside only. I will get on the trouble shooting in my doors where there is no wiggle room to move or work. Thanks again guys >>>>>>>>>>>>>
My 78 has new power door lock actuators. If the doors are unlocked, the drivers side lock switch will lock BOTH doors. But that is all that works. The drivers side switch will not unlock either door, and the passenger side switch does nothing. Thoughts? Do I need to replace the wiring harnesses and switches on both sides? I’ve unplugged all the connections and cleaned the pins and connections with a wire brush. Appreciate any others suggestions.
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
When the switch is activated, electrical current is directed to the actuator. The electrical activates or moves a plunger in the electro-mechanical actuator and its the plunger that moves the linkage to either lock or unlock the door..
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Safety Car
Joined: Apr 2018
Posts: 4,592
Likes: 44
From: Eastpointe MI
My 78 came with dead power locks and bad switches. Rather than go to the expense of replacing the switches and plugs (mine had wires falling off), I just picked up a remote keyless entry amd a couple ice cube relays. Cheaper and more useful too.
Safety Car
Joined: Apr 2018
Posts: 4,592
Likes: 44
From: Eastpointe MI
The key cylinder? You aren't mistaking the factory alarm switch on the driver side lock cylinder for a lock actuator, are you?
Advanced
Joined: Feb 2019
Posts: 80
Likes: 41
From: Oneida, N.Y.
The ones in my '79 didn't work when I got it, found the ground wire on the passenger side door mounted to a painted surface for one, and both connectors at each switch had minor oxidization.
PLUS the contacts inside the connectors were stretched and not touching the pins. I managed to get behind them with a small nail and bend them back tighter, then they worked. Finally.
PLUS the contacts inside the connectors were stretched and not touching the pins. I managed to get behind them with a small nail and bend them back tighter, then they worked. Finally.
Intermediate
Joined: Jan 2013
Posts: 26
Likes: 0
Power door locks
Hi l opened my door panels to replace my power door locks in my 79 c3 and low n behold l only have power to the drivers side? The pass side is manual, is this normal?
My 78 has new power door lock actuators. If the doors are unlocked, the drivers side lock switch will lock BOTH doors. But that is all that works. The drivers side switch will not unlock either door, and the passenger side switch does nothing. Thoughts? Do I need to replace the wiring harnesses and switches on both sides? I’ve unplugged all the connections and cleaned the pins and connections with a wire brush. Appreciate any others suggestions.
[/QUOTE]
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
Is this what you're asking?
You dropped the HTML quote characters for this second part which is confusing whether your questions continued or this quote (from initial OP) was just dangling.
My 78 has new power door lock actuators. If the doors are unlocked, the drivers side lock switch will lock BOTH doors. But that is all that works. The drivers side switch will not unlock either door, and the passenger side switch does nothing. Thoughts? Do I need to replace the wiring harnesses and switches on both sides? I’ve unplugged all the connections and cleaned the pins and connections with a wire brush. Appreciate any others suggestions.