Windshield washer pump won't stop

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Mar 24, 2025 | 09:02 PM

stoney12

Thread Starter

7th Gear

Joined: Sep 2022

Posts: 7

Likes: 1

From: Utah, USA

Windshield washer pump won't stop

Background: This is my 1st C5 Tech post, recently purchased a C5 and discovered it has some electrical issues (surprise, surprise). Started throwing codes randomly - from what I've read here it's likely grounding issues. So I started by cleaning the two ground splice boxes behind the headlamps. Turned out they were very clean, no corrosion. Previous owner never drove her in the wet. Cleared the codes and ran fine without any issues. Current issue: While driving the other day my windshield washer pump randomly turned on and pumped all the fluid out (was kinda funny actually). Pulled the fuse to turn it off. I wonder if this is also a ground-related issue. Anyone know which ground point I should look at for the washer pump? Or any other suggestions about how to troubleshoot this? Thanks in advance.

Last edited by stoney12; Mar 24, 2025 at 10:44 PM.

Mar 25, 2025 | 09:07 AM

lucky131969

Tech Contributor

Joined: Jan 2007

Posts: 19,342

Likes: 1,123

From: Dyer, IN

Quote:

Originally Posted by stoney12

For a car that has never seen rain(or probably driven on snow for that matter) corroded ground points are the LEAST likely cause of your DTCs. Unfortunately, people read the forums and grasp on to what they think are "quick fixes". Troubleshoot the problem. A bad ground will not cause your washer pump to run continuously. Do you own a service manual set? Can you read schematics? Do you own a test light and a DMM?

Mar 25, 2025 | 10:31 AM

stoney12

Thread Starter

7th Gear

Joined: Sep 2022

Posts: 7

Likes: 1

From: Utah, USA

Thank you for sharing your insights. I do not own a service manual set. No I don't read schematics but it's something I can learn. I do own a test light and DMM.

Mar 25, 2025 | 11:00 AM

C5 Diag

Moderator, Tech Contributor

Joined: Sep 2013

Posts: 15,412

Likes: 3,964

From: Cape Coral, Florida

If your washer pump operates with key on disconnect the wiper/washer connector…if the washer still operates you have a short to VOLTAGE in the washer circuit…if the pump does not operate you have a bad switch.

Mar 31, 2025 | 10:41 AM

stoney12

Thread Starter

7th Gear

Joined: Sep 2022

Posts: 7

Likes: 1

From: Utah, USA

Quote:

Originally Posted by C5 Diag

Thank you for the diagnostic suggestion. I was able to get to it this weekend - When I disconnected the wiper/washer, there was no longer power to the pump with the key on. Replacement wiper/washer switch is on its way.