Issue with door locks

Tiny
BABYJAY531
  • MEMBER
  • 1996 GMC C1500
  • 4.6L
  • 6 CYL
  • 4WD
  • MANUAL
  • 245,000 MILES
My door locks do not work I have used a test light and a multimeter I have voltage and power my windows work I tested the actuators with the battery. They moved I am at a dead end, what can I do?
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Sunday, March 5th, 2017 AT 4:59 PM

4 Replies

Tiny
CARADIODOC
  • EXPERT
Since you are already down to the actuators, check for voltage on both wires when you press the lock switch. When you push it to "lock", you should have 12 volts on just on of the wires at the actuator. If you have 12 volts on both wires, you will also have it on both in the "unlock" position. That indicates the ground is missing. The best suspect for that is a broken wire between the door hinges.

That can also be caused by a bad switch, but most of the time the locks will still work from the other switch. The better clue is a bad switch will usually work for "lock" OR "unlock", but not both. The clinker is either switch can cause only the other one to not work, but again, it's not common for both the "lock" and "unlock" functions to fail at the same time.
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Sunday, March 5th, 2017 AT 5:26 PM
Tiny
BABYJAY531
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I will check for that tomorrow morning and I will let you know
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Sunday, March 5th, 2017 AT 5:57 PM
Tiny
BABYJAY531
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I know one time I did that. It read 0 volts when I tested it last week. I did it to both wires.
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Sunday, March 5th, 2017 AT 5:59 PM
Tiny
CARADIODOC
  • EXPERT
Check both wires with the switch in "lock", then check both again with it in "unlock". If you always find 0 volts on both wires, the 12 volt supply is missing, typically due to a broken wire or blown fuse. If you find 12 volts on both wires at the same time, the ground is missing, That is usually due to a broken wire. It can be due to a bad switch, but two sets of contacts would have to fail, and that isn't common.
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Tuesday, March 7th, 2017 AT 10:18 AM

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