C3 Ground(s) how? where?
Thread Starter
Le Mans Master
Joined: Nov 2000
Posts: 5,210
Likes: 104
From: Fort Worth TX
St. Jude Donor '06
Father & Son St. Jude Donor '09
C3 Ground(s) how? where?
My 74's windsheild wiper motor has had trouble for several months now. Last night, I finally figured out a pattern. I can get the wiper motor to run 100% when the hood is unlatched and either door is ajar. I tested the door jamb interior light button and no change.
Since the hood latches and the vert door latches are metal and make solid contact, it make me think my C3's ground system is being disturbed.
So, how and where are all of the ground connections on a C3?
Any other ideas?
Since the hood latches and the vert door latches are metal and make solid contact, it make me think my C3's ground system is being disturbed.
So, how and where are all of the ground connections on a C3?
Any other ideas?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Grounds are all over- left door jamb just above the hood release, right engine support to the block, down by the starter on the back of the block (that's the one I'd look at FIRST!)
8th Gear
Joined: Nov 2005
Posts: 8
Likes: 0
From: AUSTIN TX
Wiper and ground
Back in the 80s I noticed that every time it rained my battery would go dead. The 69 had a few elec issues so I just thought I had to live with it and had a few other vehicles do drive in the rain. The 68 had even more elec issues! The wipers did not even work I just used rainx and drove fast. I replaced the motor. They still did not work and the wire was hot when the switch was on. I would switch it on sometimes in the rain just in case it decided to work. I always leave the hood up in the garage. After coming home from a wet day I happened to be leaning over the wiper motor and noticed it was very warm. Too warm. It was not grounded I grounded it. Still works fine.
Thread Starter
Le Mans Master
Joined: Nov 2000
Posts: 5,210
Likes: 104
From: Fort Worth TX
St. Jude Donor '06
Father & Son St. Jude Donor '09
Yes, mine is too warm too. Thank, that helps me to confirm a bad ground as the culprit.
Le Mans Master
Joined: Aug 2006
Posts: 7,426
Likes: 1,559
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
On the wiper motor there is a 3 plug connector, next to that is a single black wire that connects to a male spade terminal, the other end of that black wire should be connected to a starter bolt or a bell housing bolt.
The wiper switch inside the car must also be grounded. Take a wire and hook it to one of the little nuts that hold the wiper switch in behind the bezel and bolt the other end of that wire to a good ground.
That should fix that, PG.
The wiper switch inside the car must also be grounded. Take a wire and hook it to one of the little nuts that hold the wiper switch in behind the bezel and bolt the other end of that wire to a good ground.
That should fix that, PG.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
its not actually a bad ground, it is just a ground connected to power. Fortunately it only runs the wiper motor and the fan. follow the black wire down to the starter, you will probably find it attached to the battery cable on the starter. Common mistake, it looks like it goes there, but should be on a bellhouse bolt.
Thread Starter
Le Mans Master
Joined: Nov 2000
Posts: 5,210
Likes: 104
From: Fort Worth TX
St. Jude Donor '06
Father & Son St. Jude Donor '09
Originally Posted by petes74ttop
On the wiper motor there is a 3 plug connector, next to that is a single black wire that connects to a male spade terminal, the other end of that black wire should be connected to a starter bolt or a bell housing bolt.
The wiper switch inside the car must also be grounded. Take a wire and hook it to one of the little nuts that hold the wiper switch in behind the bezel and bolt the other end of that wire to a good ground.
That should fix that, PG.
The wiper switch inside the car must also be grounded. Take a wire and hook it to one of the little nuts that hold the wiper switch in behind the bezel and bolt the other end of that wire to a good ground.
That should fix that, PG.
The wiring schematic indicates that the same ground wire connects to the door and hood alarm switches so that's probably why the motor worked with the hood and one door ajar.
its not actually a bad ground, it is just a ground connected to power. Fortunately it only runs the wiper motor and the fan. follow the black wire down to the starter, you will probably find it attached to the battery cable on the starter. Common mistake, it looks like it goes there, but should be on a bellhouse bolt.
That black wire disappears into a wiring harness.
THANKS AGAIN FOR ASSISTANCE!
Thread Starter
Le Mans Master
Joined: Nov 2000
Posts: 5,210
Likes: 104
From: Fort Worth TX
St. Jude Donor '06
Father & Son St. Jude Donor '09
Follow up on the solution for everyone.
I did some trouble shooting and convinced myself it was a bad ground. I started to run a new ground and abandon the factory wire. I figured the new ground wire should be connected to something near the starter so I jacked her up and got underneath looking for a good place to connect the wire. While I was under the car, I decided to check the grounds. One was clean and solid, a second, the on from the starter to the bell housing was loose, greasy and dirty. It took me a while to clean up the years of crud, remove the bolt, clean the bolt, ground wire connector and wire strap but after everything was all done and back together, THE WIPER MOTOR WORKED! It's always nice when you find the problem and fix it properly.
Thanks again for all the tips.
I did some trouble shooting and convinced myself it was a bad ground. I started to run a new ground and abandon the factory wire. I figured the new ground wire should be connected to something near the starter so I jacked her up and got underneath looking for a good place to connect the wire. While I was under the car, I decided to check the grounds. One was clean and solid, a second, the on from the starter to the bell housing was loose, greasy and dirty. It took me a while to clean up the years of crud, remove the bolt, clean the bolt, ground wire connector and wire strap but after everything was all done and back together, THE WIPER MOTOR WORKED! It's always nice when you find the problem and fix it properly.
Thanks again for all the tips.
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