Wipers Won’t Turn Off? Here’s How I Diagnosed a 2021 Dodge Challenger Electrical Nightmare
If you’ve ever run into a situation where the windshield wipers won’t shut off no matter what you do, you know how frustrating—and confusing—it can be. This is one of those problems that can easily lead to misdiagnosis, wasted parts, and unnecessary programming if you’re not careful.
In this case, we were working on a 2021 Dodge Challenger with wipers stuck running continuously. At first glance, it looked like a failed module. But as you’ll see, the real issue was something far more deceptive—and a perfect example of why proper automotive troubleshooting matters.
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Autel MaxiSys MS906 Pro TS Scanner
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Power Probe ECT3000 Short Finder
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Vehicle Overview
2021 Dodge Challenger
Modern CAN-based electrical architecture
Steering Column Control Module (SCCM) controls wipers, turn signals, and steering wheel functions
Vehicle Concern
The main symptom was straightforward:
Wipers running continuously
No response from the switch
Intermittent or no control from the steering column
This kind of issue is often tied to either:
A faulty SCCM
A communication problem
Or a wiring issue
Initial Inspection
The vehicle had already been worked on previously. A steering column component had been replaced, and there was a recommendation to replace and program the SCCM.
Right away, that raises a red flag. Throwing parts at a problem without confirming the failure is one of the most common mistakes in diagnosing car problems.
So we started fresh.
Codes
A full system scan revealed multiple communication faults:
U0212 – Lost communication with SCCM
U0126 – Lost communication with steering angle sensor
Additional U-codes across multiple modules
These codes were active and returned immediately after clearing.
That tells you one thing:
This is not a history issue or low voltage event—this is a current, hard fault.
Diagnostic Process
The first step in automotive troubleshooting like this is verifying whether the module is even alive.
Using the scan tool topology, the SCCM showed up as non-communicating. That’s critical.
At this point, you’ve got three possibilities:
The module is bad
The module has no power or ground
The network is down
Since other modules were communicating fine, we ruled out network failure.
Next step: check power and ground at the SCCM.
Ground tested good. But the power feed? Only about 2 volts.
That’s a big clue.
A healthy circuit should show full battery voltage—around 12 volts. Seeing 2 volts usually means you’re dealing with an open circuit or high resistance somewhere in the wiring.
To confirm, we performed a simple but powerful test:
We backfed 12 volts directly into the power circuit at the SCCM.
The result?
The module came alive, and the wipers immediately stopped and parked correctly.
That tells you everything you need to know:
The module is good. The problem is in the wiring.
Key Findings
At this point, we knew we had a voltage drop between the fuse and the SCCM.
Tracing the circuit back, the power feed originated from a fuse in the rear fuse box.
So we moved to the trunk area and started inspecting the harness.
Once the harness was opened up, the problem became obvious:
Severe corrosion inside the wiring near the battery.
This is something a lot of people overlook. Battery acid fumes can travel into the wiring harness and cause corrosion inside the insulation. From the outside, the wire may look fine—but inside, it’s completely compromised.
We found:
Swollen insulation
Corroded copper
One wire completely eaten through
Final Diagnosis
The root cause was:
Open/high resistance in the SCCM power feed circuit due to corrosion in the rear wiring harness near the battery
This caused:
Loss of power to SCCM
No communication with modules
BCM defaulting wipers to ON (fail-safe mode)
Repair
The repair process included:
Removing the battery and exposing the affected harness
Neutralizing acid contamination
Cleaning and drying the area thoroughly
Cutting out damaged sections of wiring
Installing new wire using solder and heat shrink
Rewrapping the harness to factory condition
After reassembly, everything worked as it should:
SCCM communicated properly
Wipers operated normally
No more fault codes
And importantly—no programming was required. The module was fine the entire time.
Common Causes
This type of issue falls into a category many techs miss:
Battery acid contamination
Hidden harness corrosion
High resistance wiring faults
Misdiagnosed module failures
It’s a perfect example of why understanding symptoms and testing properly matters.
Lessons for Buyers / DIYers
If you’re into diagnosing car problems or doing your own automotive troubleshooting, here are a few takeaways:
Don’t assume a module is bad just because it’s not communicating. Always verify power and ground first.
Voltage readings can be misleading. Seeing a few volts doesn’t mean the circuit is good—it often means the opposite.
Continuity tests and tone tracers don’t always catch high resistance faults. Load testing and voltage drop testing are far more reliable.
If you’re inspecting a used vehicle, pay close attention to the battery area and wiring harnesses. Corrosion here can cause all kinds of electrical nightmares down the road.
Don’t Get Burned on Your Next Used Car
If you’re thinking about buying a used car—or even if you already have one—this is exactly the kind of problem that can slip through the cracks and cost you big money later.
After 35+ years in the automotive field, I’ve seen firsthand how often people end up with vehicles that have hidden issues just like this.
That’s why I put together a simple Used Car Guide to help you understand what to look for and how to avoid making a costly mistake.
It’s a quick, practical guide designed to give you the right mindset and approach before you buy.
👉 https://stan.store/BobbyWhiteside
Affiliate Disclaimer
Disclaimer: Some links in this post may be affiliate links. I may earn a small commission at no extra cost to you. I only recommend tools I personally use and trust in real-world diagnostics.
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