Shop

Shop
Power Tools
Hand Tools
Air Tools & Compressors
Tool Storage & Organization
Automotive
Generators & Engines
Lawn & Garden
Home & Security
Welding
Plumbing
Electrical
Hardware
Material Handling
Building & Construction
Painting
Lighting
Safety

Order Status
My Account
Contact Us
Product Support
Find a Store

Home
Automotive
Auto Shop Tools
Electrical

12v Automotive Extensions

9 Items

NEW
AMES INSTRUMENTS
Pen Voltage Tester with GFCI Diagnosis
Pen Voltage Tester with GFCI Diagnosis
^$24⁹⁹
Was ^$~~29.99~~Save 17%
Add to My List
CEN-TECH
100A 6/12V Battery Load Tester
100A 6/12V Battery Load Tester
^$19⁹⁹
In-Store Only
Add to My List
PITTSBURGH AUTOMOTIVE
12V Remote Starter Switch
12V Remote Starter Switch
^$11⁹⁹
Add to My List
CEN-TECH
12V Battery/Alternator Tester
12V Battery/Alternator Tester
^$6⁹⁹
In-Store Only
Add to My List
CEN-TECH
6/12V Circuit Tester with 5 ft. Lead
6/12V Circuit Tester with 5 ft. Lead
^$3⁹⁹
Add to My List
CEN-TECH
6/12V Circuit Tester
6/12V Circuit Tester
^$2⁹⁹
Add to My List
Clearance
THUNDERBOLT MAGNUM
12V Dual Outlet Adapter
12V Dual Outlet Adapter
^$4⁴⁷
Add to My List
Clearance
THUNDERBOLT MAGNUM
12V 9 ft. Extension Cord
12V 9 ft. Extension Cord
^$3⁹⁷
In-Store Only
Add to My List
Clearance
PITTSBURGH AUTOMOTIVE
12V Alternator/Battery Tester
12V Alternator/Battery Tester
^$2⁴⁷
Add to My List

Save Even More with the Harbor Freight Credit Card

Get 10% Off Your Entire Purchase When You Open a New Account

Learn More

Sign Up Today to Start Saving!

Get our best deals and latest news delivered straight to you

Helpful Links

Need Help?
Store Finder
Gift Cards
Order Status

Customer Service

Contact Us
Order Status
Shipping & Delivery
Manage Credit Card
Return Policy
Replacement Parts
Extended Service Protection
Recall & Safety

About Us

Our Story
Careers
Real Estate
Giving Back

Connect with Harbor Freight Tools

facebook
youtube
twitter
instagram
pinterest
linkedin
tiktok

How We Sell GREAT Tools at the Lowest Prices

We have invested millions of dollars in our own test labs and factories, so our tools will go toe-to-toe with the top professional brands. And we can sell them for a fraction of the price because we cut out the middleman and pass the savings on to you. It's just that simple!

If You Buy Your Tools Anywhere Else, You're Throwing Your Money Away!

No Hassle Return Policy
100% Satisfaction Guaranteed

Security & Privacy
Do Not Sell My Personal Information
Privacy Settings
Terms & Conditions
CA Transparency in Supply Chains Act
Supplier Code of Conduct

Don't get scammed by websites pretending to be Harbor Freight. Learn More

For any difficulty using this site with a screen reader or because of a disability, please contact us at 1-800-444-3353 or cs@harborfreight.com.

For California consumers: more information about our privacy practices.