Door Ajar Switch Replacement
Thread Starter
Pro
Joined: Oct 2000
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From: Vancouver, B.C., Canada
Door Ajar Switch Replacement
So I need, or want, to replace my door ajar switches (both sides). Alarm is not used. Car has a modern alarm system.
Driver side mounting plate is missing. Two questions:
1. Looks like the mounting plate pop rivets on the back side of the fiberglass structure. Yes/no? Any tips to doing this.
2. The wiring connections to the door switches look difficult to change over. Do they just pull out of the white plastic housing? Any tips to doing this? They look very fragile.
Driver side mounting plate is missing. Two questions:
1. Looks like the mounting plate pop rivets on the back side of the fiberglass structure. Yes/no? Any tips to doing this.
2. The wiring connections to the door switches look difficult to change over. Do they just pull out of the white plastic housing? Any tips to doing this? They look very fragile.
Team Owner
Joined: Sep 2006
Posts: 31,172
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From: Westminster Maryland
Hi K,
Remember the front and rear switches control both the door ajar warning light and courtesy lights in addition to the alarm. So if you want those to work you'll need to get all 4 of them operating.
The switch and connectors are available from various vendors and the new connectors can be crimped on to the ends of the existing wires.
Regards,
Alan
Remember the front and rear switches control both the door ajar warning light and courtesy lights in addition to the alarm. So if you want those to work you'll need to get all 4 of them operating.
The switch and connectors are available from various vendors and the new connectors can be crimped on to the ends of the existing wires.
Regards,
Alan
Thread Starter
Pro
Joined: Oct 2000
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From: Vancouver, B.C., Canada
Thanks Alan.
My front switches are working fine. No problems there although I might buy new ones anyway.
Do the switches come with new connectors? Most photos I see from vendors don't show the connectors with the switches.
My front switches are working fine. No problems there although I might buy new ones anyway.
Do the switches come with new connectors? Most photos I see from vendors don't show the connectors with the switches.
Safety Car
Joined: Apr 2006
Posts: 4,057
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From: BC
You buy the connectors separately. You can use the original connectors if you use a sharp thin tool or very small hobbyist's screw driver and slide it into the end cap and release the tab holding the connector. The tab is on the other side (not shown) of the connectors in Alan's pic and keeps the connector from sliding back out but it can be removed easily.
Last edited by CanadaGrant; Feb 28, 2016 at 07:54 PM.
Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Yes! You have to ground the plate.
Pink brings 12 volts to the bulb and the blue supplies the ground, but the plate is mounted if fiberglass and that is why you need a separate ground.
http://www.vetteprojects.com/bmv/mis...tte%201972.pdf
Pink brings 12 volts to the bulb and the blue supplies the ground, but the plate is mounted if fiberglass and that is why you need a separate ground.
http://www.vetteprojects.com/bmv/mis...tte%201972.pdf
Last edited by Peterbuilt; Mar 2, 2016 at 10:08 PM.
Safety Car
Joined: Apr 2006
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From: BC
I don't think the plate was grounded from the factory or requires it. All the door ajar switch does is complete the ground from the warning light as the positive to the light is live at all times. Check the wiring diagram again. The ajar switch controls/completes the ground.
Last edited by CanadaGrant; Mar 3, 2016 at 12:45 AM.
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Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
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I don't think the plate was grounded from the factory or requires it. All the door ajar switch does is complete the ground from the warning light as the positive to the light is live at all times. Check the wiring diagram again. The ajar switch controls/completes the ground.
Drifting
Joined: Aug 2006
Posts: 1,727
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From: Scottsdale Arizona
I had to fix mine also I purchased the backing plate from Paragon and it was the right shape
This what it looks like with part of the inner fender removed. I am doing a body off so it was easy to access.
This what it looks like with part of the inner fender removed. I am doing a body off so it was easy to access.
Drifting
Joined: Jul 2015
Posts: 1,765
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From: Catlett VA
Yes, the plate was indeed grounded at the factory. This tip was provided by Ernie from Willcox a few years ago. He had a pic of an original plate but it has now vanished. This was his description of the plate, " The third hole is for the ground wire and the screw was a slotted head screw".
Anyways 69FastFun's plate sure looks easier to work with and appears to have the hole pre drilled for the ground wire. Just looked at his vendors site at PN# 16095 and it looks identical to the one I had to shave down and solder a lug to.
Maybe 69FF can share his part #.
Anyways 69FastFun's plate sure looks easier to work with and appears to have the hole pre drilled for the ground wire. Just looked at his vendors site at PN# 16095 and it looks identical to the one I had to shave down and solder a lug to.
Maybe 69FF can share his part #.
Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
The courtesy light switches are up front and screwed into the metal door frame so they do not need a separate ground wire.
The ORIGINAL and bestest
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From: Toronto Ontario
Toronto Events Coordinator
I don't think the plate was grounded from the factory or requires it. All the door ajar switch does is complete the ground from the warning light as the positive to the light is live at all times. Check the wiring diagram again. The ajar switch controls/completes the ground.
This is correct, this is how it is on my car. Maybe later C3's are different. The rear pin switches have 3 wires:
-black for ground reference
-blue for ground to door ajar light
-white for ground to alarm relay
When the door is opened, the switch contacts close together and connect all 3 wires together. Early C3's without the factory alarm system only have 2 wires, the black and blue, as Alan71's pic shows.
Thread Starter
Pro
Joined: Oct 2000
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From: Vancouver, B.C., Canada
Wow, some conflicting opinions on this thread!! I guess I'll have to open up behind the switch and see just what's in there. My passenger side looks intact and should provide the answers.
Safety Car
Joined: Apr 2006
Posts: 4,057
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From: BC
Look at the wiring diagram posted above. Follow the door ajar switch wiring. The switch provides the connection for the negative wire(s) to the ground wire. It does not ground out through the switch body or mounting plate. A ground wire from the mounting plate does not benefit anything.
Last edited by CanadaGrant; Mar 4, 2016 at 12:25 PM.