All of my rear lights stopped working with no warning. My blind spot monitoring and cross traffic detection also stopped working. This is a serious issue as the light go out intermittenly without warning. Especially dangerous at night. Dealership thinks it might be a faulty harness. Dealership thought they fixed it by cleaning contacts but the very next day they went out again while driving in a…
2021 Ford F-250 electrical problems
severe 14 complaints filed with NHTSA · avg repair $850 · see electrical across all vehicles →
Complaints
14
Recalls
0
Avg fix
$850
1crash
When does it fail?
Of the 14 electrical complaints filed for the 2021 Ford F-250, here's the actual mileage breakdown — failures cluster heaviest at 50,000-75,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
The failure pattern owners describe
The 2021 F-250 electrical system exhibits a pattern of moisture-related failures tied to rain, fog, and wet conditions. Powertrain Control Module communication breaks down repeatedly, flooding the dash with fault messages about glow plugs, exhaust sensors, and transmission data—leading to hard starts or complete no-starts. Owners report incidents recurring even after dealers replace the DEF wiring harness or Battery Junction Box, and one truck surged uncontrollably while parked. The Battery Junction Box itself absorbs moisture and fails, cutting all communication with the fuse box; one owner was denied warranty coverage after mileage exceeded original limits by 900 miles. Batteries swell and explode; one had already been replaced in 2021 before exploding again at 52,000 miles. The entire driver-side wiring harness sits submerged in water pooling in the bed, requiring bed removal to fix properly. Tow mirrors cannot adjust for switching between standard and towing setups, creating blind spots and near-accidents, though Ford issued a service message with a cleaning procedure that dealers either don't know about or refuse to perform. Rear lights fail intermittently in snow without warning. Horns stick on or fail to sound; at least one was linked to moisture in the Battery Junction Box. Front cameras go black and block forward collision alerts. Trailers lose braking function mid-drive. One owner hit an elk at 65 mph; airbags did not deploy and no crash warning sounded despite severe damage.
Same Ford F-250 electrical reports on nearby years: 2020 · 2022 · 2023
Failure modes owners describe
Powertrain Control Module Communication Loss & Message Flooding
Multiple fault codes flood the dash when the PCM loses communication with glow plug, exhaust particulate matter sensor, and other modules. Hard start or no-start conditions follow. Incidents clustered around moisture exposure (rain, fog, overnight damp conditions). One owner reports the truck surging while parked.
When: Multiple incidents: initial rain-triggered event, second rain-triggered event during cross-country travel, third event after overnight rain despite dry roads at time of failure. Mileages not specified.
Symptoms owners cite: Service engine soon light with six fault messages including PCM communication loss; Hard start or no-start condition; Vehicle surging while parked; Pre-collision assist unavailable message; Transmission control module sending invalid data over network
Codes mentioned: Glow plug communication fault, Exhaust particulate matter sensor communication loss, Vehicle network communication fault between multiple modules, Transmission control module invalid data, Pre-collision assist unavailable
Repairs/costs cited: DEF wiring harness replaced at Archie Cochrane Ford; Battery Junction Box replaced at Larry H Miller Ford. Issues recurred.
Battery Junction Box Moisture Intrusion & Electrical Failure
Moisture enters the Battery Junction Box, causing no-start and loss of communication with the fuse box. One dealer visit resulted in no repair attempted due to moisture in the component. A second owner reports BJB moisture requiring replacement. Horn failures also traced to moisture in BJB.
When: Approximately 73,000 miles (one case); mileage not specified in others. One owner was just outside warranty by 900 miles.
Symptoms owners cite: Vehicle parked, running, then shut off with no restart; No warning lights before failure, multiple unknown warnings after; Vehicle not communicating with fuse box; Moisture visible in fuse box/BJB; Horn stuck on even with truck off
Codes mentioned: Vehicle network communication loss, Fuse box communication fault
Repairs/costs cited: Battery Junction Box replacement; moisture present inside component. One case not repaired. Horn issue resolved by disconnecting battery and removing fuse.
Recalls/TSBs owners mention: Dealer advised filing NHTSA complaint; no warranty coverage for moisture-damaged BJB when mileage exceeded original warranty period
Swollen Battery & Fire Risk
Battery swells internally, creating fire hazard. Roadside Assistance detected abnormal odor under hood and identified swollen battery as potentially dangerous. One battery exploded and leaked acid; this battery had been replaced once already in 2021.
When: Approximately 30,000 miles (first incident); approximately 52,000 miles (second incident with battery explosion/acid leak)
Symptoms owners cite: TPMS warning light illuminated; Abnormal odor from engine bay; Battery visibly swollen; Battery explosion and acid leak
Codes mentioned: TPMS fault (may be coincidental to tire puncture)
Repairs/costs cited: Battery replaced by Roadside Assistance at 30,000 miles. Second battery replaced at AutoZone at 52,000 miles after explosion.
Recalls/TSBs owners mention: Manufacturer advised filing NHTSA complaint
Driver-Side Wiring Harness Water Intrusion
Entire driver-side wiring harness sits submerged in water pooling inside the truck bed area. Water pours from rear plugs when vehicle is driven. Requires bed removal for proper repair. Owner states this is widespread among 2021 F-250s and should be a recall.
When: Issue discovered after truck wash; water exposure and pooling evident
Symptoms owners cite: Water pooling under driver-side floor mats; Water pouring from rear plugs; Wiring harness completely submerged
Repairs/costs cited: Proper repair requires removal of truck bed to address water pooling and wiring exposure
Tow Mirror Adjustment Failure
Driver and passenger tow mirrors cannot fully adjust or lock in position for either standard driving or towing configurations. Ford issued Special Service Message #51829 with a cleaning procedure, but dealers either lack awareness of it or refuse to perform it without charge. Owner reports near-accidents due to mirror blind spots. Affects 2017–2023 F-150, F-250, and F-350 trucks.
When: Ongoing, present at complaint filing
Symptoms owners cite: Mirrors will not adjust to full range; Mirrors cannot switch properly between towing and non-towing positions; Blind spots in driver's view due to misalignment
Repairs/costs cited: $250 diagnostic fee requested by dealership; mirror cleaning procedure exists but dealers claim lack of information or refuse to share procedure
Recalls/TSBs owners mention: Special Service Message #51829 issued covering 2017–2023 F-150, F-250, F-350 models with tow mirrors. Cleaning procedure part of diagnostics. Owners report Ford attempting to block warranty claims.
Rear Lighting Harness Intermittent Failure
All rear lights fail simultaneously without warning. Blind spot monitoring and cross-traffic detection also cut out. Happens intermittently, especially during snow storms. Dealer suspected faulty harness; attempted fix by cleaning contacts failed—lights went out again the next day during snow.
When: Failure occurs during snow and wet weather conditions; mileage not specified
Symptoms owners cite: All rear lights go out; Blind spot monitoring stops working; Cross-traffic detection stops working; Failures occur without warning, especially in snow
Repairs/costs cited: Dealer cleaned contacts in harness; repair did not hold—lights failed again next day
Horn Continuous Operation & Malfunction
Horn either stays on even with truck off (requiring battery disconnect and fuse removal) or fails to sound. One case linked to moisture in Battery Junction Box.
When: One case at unspecified mileage; another at 63,000 miles
Symptoms owners cite: Horn will not turn off even with truck off; Horn does not function when needed; No warning lights before horn failure
Repairs/costs cited: One case: horn fuse removed and battery disconnected as workaround; BJB with moisture replaced. Other case: dealer diagnosed horn failure but did not repair.
Recalls/TSBs owners mention: Dealer stated moisture-damaged BJB not a recall issue; manufacturer case opened after contact
Forward Collision Alert & Camera Malfunction
Front camera goes black and stops functioning. Forward collision alert system blocked from operating. Owner reports Ford refusing to acknowledge the issue or investigate for recall.
When: Mileage not specified
Symptoms owners cite: Front camera display goes black; Camera stops functioning; Forward collision alert system disabled
Recalls/TSBs owners mention: Ford refuses to acknowledge issue or investigate recall
Trailer Brake Wiring Fault Message & No Response
While towing an Arctic Wolf travel trailer, trailer brake fails to respond and message 'trailer brake wiring fault' appears on display. Owner did not pursue diagnosis or repair.
When: Approximately 19,234 miles
Symptoms owners cite: Trailer brake unresponsive while driving at 30–50 MPH; Trailer brake wiring fault message displayed
Codes mentioned: Trailer brake wiring fault
Cat-Like Odor in Cabin During Wet Conditions
Strong cat-like odor detected in cabin after car wash or during rain, especially when A/C is in recycle mode. Dealer sprayed air filter and checked for dead animals; no resolution. Separate body shop replaced weather strip. Root cause not definitively determined.
When: Approximately 43,000 miles
Symptoms owners cite: Cat-like odor in cabin; Odor triggered by car wash or inclement weather; Odor intensified with A/C in recycle position; Weather strip molding detached
Repairs/costs cited: Air filter sprayed; dead animal check performed at dealer. Weather strip replaced by body shop.
Airbag Non-Deployment in High-Speed Collision
Driver hit an elk at 65 mph while towing a loaded flatbed trailer. Airbags did not deploy and crash warning light did not illuminate, despite severe front-end damage. Owner questions safety of repaired vehicle.
When: Incident at 65 mph
Symptoms owners cite: Crash warning light did not illuminate; Airbags did not deploy despite severe impact damage; No alert before collision
Repairs/costs cited: Vehicle sent to body shop for collision repair
Recalls/TSBs owners mention: Ford dealer directed owner to body shop; offered no assistance regarding airbag/crash detection failure
Synthesized from 14 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
The contact owns a 2021 Ford F-250. The contact stated while driving 45 MPH and attempting to alert another driver, the contact became aware that the horn was not functioning properly. No warning lights were illuminated. The vehicle was taken to the dealer, who diagnosed a failure with the horn. The vehicle was not repaired. The manufacturer was notified of the failure, and a case was opened. The…
Both the driver and passenger mirrors will not fully adjust. The mirrors need a different adjustment for standard driving and when towing a travel trailer. Neither mirror will properly adjust for towing and non towing applications. The lack of proper mirror adjustment causes a safety issue as the driver cannot see things in their full scope due to the mirror misalignment. I have almost had…
Had electrical trouble with your 2021 Ford F-250?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the electrical problem on the 2021 Ford F-250?
It's a meaningful issue. 14 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $850.
At what mileage does the electrical typically fail?
Based on the 14 complaints filed, electrical issues most often appear around 46,706 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $850 for electrical repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to electrical?
No active recalls currently cover electrical issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Ford/F-250.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.