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Safety-Air-Electrical

Shop semi truck gladhands, air tanks, semi-trailer cords, 7-way receptacles and more. We stock premium aftermarket replacement air system and electrical components to maintain your truck’s critical air line connections.
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  • FREE SHIPPING OVER $249
    14 Gauge Red Electrical Wire - Sold Per Foot

    14 Gauge Red Electrical Wire - Sold Per Foot

    PARTS DISTRIBUTING

    $2.03
    14 Gauge Red Electrical Primary WireBuy 14 Gauge Red Electrical Wire at 4 State Trucks! Our wire is sold by the foot. It will be shipped as a continuous length to meet your project needs, up to a...
    EL61402301
    SKU:
    EL61402301
    Color:
    Red
    Truck Class:
    Universal
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $2.03
    Qty in Cart: 0
    Price:
    $2.03
    Subtotal:
  • FREE SHIPPING OVER $249
    1 Gauge 3/8 Inch Heavy Wall Lug

    1 Gauge 3/8 Inch Heavy Wall Lug

    TRAMEC SLOAN

    $5.09
    Heavy Wall Battery Lug* High Quality Battery Lug* 1 Gauge 3/8 Inch* Sold Individually* Features Color Coding* Made With Electrolytic Copper* Warranty On Lug Against Defects In Workmanship & Material...
    EL431038
    SKU:
    EL431038
    Truck Class:
    Universal
    Diameter Options:
    3/8 Inch
    Material Options:
    Copper
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $5.09
    Qty in Cart: 0
    Price:
    $5.09
    Subtotal:
  • Fender Wiring Harness For Kenworth

    Fender Wiring Harness For Kenworth

    WTI FENDERS

    $118.99
    Wiring Harness Fits Kenworth FendersThis Fender Wiring Harness is designed specifically for Kenworth trucks, making it easy to replace or upgrade your existing wiring. It ensures a reliable...
    EFR625826K
    SKU:
    EFR625826K
    Location:
    Made In USA
    Truck Class:
    Heavy Duty
    Make:
    Kenworth
    Product Type:
    Air, Electrical, & Safety
    $118.99
    Qty in Cart: 0
    Price:
    $118.99
    Subtotal:
  • FREE SHIPPING OVER $249
    TPHD 1/4 Inch X 1/4 Inch Pipe Adapter

    TPHD 1/4 Inch X 1/4 Inch Pipe Adapter

    TPHD

    $7.82
    1/4 Inch X 1/4 Inch Brass Pipe Adapter By TPHD* High Quality Pipe Adapter* Made Of High Quality Brass* .25 x .25 Inch* Sold Individually* Warranty On Pipe Adapter Against Defects In Workmanship &...
    BP12044
    SKU:
    BP12044
    Diameter Options:
    1/4 Inch
    Truck Class:
    Universal
    Material Options:
    Brass
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $7.82
    Qty in Cart: 0
    Price:
    $7.82
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  • 1/2 Inch Brass Recessed Hex NPT Plug

    1/2 Inch Brass Recessed Hex NPT Plug

    TRAMEC SLOAN

    $4.85
    1/2 Inch Recessed Hex NPT Plug* High Quality Hex NPT Plug* Recessed* 1/2 Inch* Hex NPT* Brass* Plug* Sold Individually* Warranty On Hex NPT Plugs Against Defects In Workmanship & Material From Date...
    BP1188
    SKU:
    BP1188
    Diameter Options:
    1/2 Inch
    Truck Class:
    Heavy Duty
    Material Options:
    Brass
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $4.85
    Qty in Cart: 0
    Price:
    $4.85
    Subtotal:
  • FREE SHIPPING OVER $249
    TPHD Brass 90 Degree 3/8 Inch Street Pipe

    TPHD Brass 90 Degree 3/8 Inch Street Pipe

    TPHD

    $11.43
    Street Pipe* High Quality Pipe Fitting* Made Of Brass* 90 Degree Street Elbow* 3/8 Inch* Sold Individually* Warranty On Pipe Against Defects In Workmanship & Material From Date Of Purchase*** High...
    BP1166
    SKU:
    BP1166
    Diameter Options:
    3/8 Inch
    Truck Class:
    Universal
    Material Options:
    Brass
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $11.43
    Qty in Cart: 0
    Price:
    $11.43
    Subtotal:
  • FREE SHIPPING OVER $249
    TPHD Brass 1/4 Inch x 3 Inch Pipe Nipple

    TPHD Brass 1/4 Inch x 3 Inch Pipe Nipple

    TPHD

    $6.86
    Pipe Nipple* High Quality Pipe Nipple* Made Of Brass* 1/4 x 3 Inches* Sold Individually* Warranty On Pipe Nipple Against Defects In Workmanship & Material From Date Of Purchase***High Quality...
    BP113430
    SKU:
    BP113430
    Diameter Options:
    1/4 Inch
    Truck Class:
    Universal
    Length Options:
    3 Inch
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $6.86
    Qty in Cart: 0
    Price:
    $6.86
    Subtotal:
  • FREE SHIPPING OVER $249
    3/8 Inch Brass Hex Pipe Collar

    3/8 Inch Brass Hex Pipe Collar

    PARTS DISTRIBUTING

    $13.89
    3/8 Inch Brass Hex Coupling Pipe Fitting* Made Of High Quality Brass* 3/8 Inch* Sold Individually* Warranty On Hex Pipe Collar Against Defects In Workmanship & Material From Date Of Purchase*** High...
    BP1036
    SKU:
    BP1036
    Diameter Options:
    3/8 Inch
    Truck Class:
    Heavy Duty
    Material Options:
    Brass
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $13.89
    Qty in Cart: 0
    Price:
    $13.89
    Subtotal:
  • FREE SHIPPING OVER $249
    TPHD 3/4 Inch Hex Pipe Collar

    TPHD 3/4 Inch Hex Pipe Collar

    TPHD

    $10.19
    3/4 Inch Brass Hex Coupling Pipe Fitting* High Quality Pipe* 3/4 Inch* Union Tee* Sold Individually* Warranty On Hex Pipe Collar Against Defects In Workmanship & Material From Date Of Purchase***...
    BP10312
    SKU:
    BP10312
    Diameter Options:
    3/4 Inch
    Truck Class:
    Universal
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $10.19
    Qty in Cart: 0
    Price:
    $10.19
    Subtotal:
  • FREE SHIPPING OVER $249
    TPHD Brass 1/4 Inch Tee Pipe

    TPHD Brass 1/4 Inch Tee Pipe

    TPHD

    $9.35
    Tee Pipe* High Quality Tee Pipe* Made Of Brass* 1/4 Inch* Sold Individually* Warranty On Tee Pipe Against Defects In Workmanship & Material From Date Of Purchase*** High Quality Aftermarket...
    BP1014
    SKU:
    BP1014
    Diameter Options:
    1/4 Inch
    Truck Class:
    Universal
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $9.35
    Qty in Cart: 0
    Price:
    $9.35
    Subtotal:
  • FREE SHIPPING OVER $249
    TPHD 1/2 Inch NPT Female 90 Degree Brass Elbow Pipe Fitting

    TPHD 1/2 Inch NPT Female 90 Degree Brass Elbow Pipe Fitting

    TPHD

    $20.68
    1/2 Inch NPT Female 90 Degree Elbow Pipe By TPHDThis TPHD Brass Elbow Pipe Fitting gives you a strong, reliable seal for a leak-proof connection. Made from durable, corrosion-resistant brass, it's...
    BP1008
    SKU:
    BP1008
    Diameter Options:
    1/2 Inch
    Truck Class:
    Universal
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $20.68
    Qty in Cart: 0
    Price:
    $20.68
    Subtotal:
  • FREE SHIPPING OVER $249
    TPHD 1/8 Inch NPT Female 90 Degree Brass Elbow Pipe Fitting

    TPHD 1/8 Inch NPT Female 90 Degree Brass Elbow Pipe Fitting

    TPHD

    $8.20
    1/8 Inch Brass 90-Deg. Pipe ElbowThe TPHD Brass 1/8 Inch NPT Female 90-Degree Elbow Pipe Fitting is designed to help create a secure connection. Made from durable, corrosion-resistant brass, it works...
    BP1002
    SKU:
    BP1002
    Truck Class:
    Universal
    Material Options:
    Steel
    Make:
    Universal Items
    Finish Options:
    Chrome-Plated
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $8.20
    Qty in Cart: 0
    Price:
    $8.20
    Subtotal:
  • FREE SHIPPING OVER $249
    30 Amp Blade Fuse - 5 Pack

    30 Amp Blade Fuse - 5 Pack

    SPECTRO WIRE

    $3.05
    ATC / ATO 30 Amp Blade Fuses* High Quality Fuse* 30 AMP* 5 Pack Spade Type* Sold Individually* Warranty On Fuses Against Defects In Workmanship & Material From Date Of Purchase*** High Quality...
    ATO30
    SKU:
    ATO30
    Color:
    Green
    Location:
    Made In USA
    Truck Class:
    Universal
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $3.05
    Qty in Cart: 0
    Price:
    $3.05
    Subtotal:
  • On Sale
    FREE SHIPPING OVER $249
    15 Amp Blade Fuse Blue - 5 Pack

    15 Amp Blade Fuse Blue - 5 Pack

    AFTERMARKET

    Now: $0.54
    Was: $5.19
    ATO 257 Series Fast-Acting Automotive Spade Type FusesThis Fuse was patented and introduced in 1976 by Littelfuse, it became the international fuse standard by 1981. It is currently found on most...
    ATO15BP
    SKU:
    ATO15BP
    Color:
    Blue
    Truck Class:
    Heavy Duty
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Now: $0.54
    Was: $5.19
    Qty in Cart: 0
    Price:
    Now: $0.54
    Was: $5.19
    Subtotal:
  • FREE SHIPPING OVER $249
    10 Amp Red Blade Fuse- 5 Pack

    10 Amp Red Blade Fuse- 5 Pack

    AFTERMARKET

    $5.29
    Littelfuse Red ATO 10 AMP FusesThis Fuse was patented and introduced in 1976 by Littelfuse, it became the international fuse standard by 1981. It is currently found on most cars, trucks, buses and...
    ATO10BP
    SKU:
    ATO10BP
    Truck Class:
    Heavy Duty
    Color:
    Red
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $5.29
    Qty in Cart: 0
    Price:
    $5.29
    Subtotal:
  • FREE SHIPPING OVER $249
    12 Volt Air Drier Wabco - Replaces 8079464, R955205, SRWABK118, 4324130010, 4324130030, 955205 & 3506784C91

    12 Volt Air Drier Wabco - Replaces 8079464, R955205, SRWABK118, 4324130010, 4324130030, 955205 & 3506784C91

    AUTOMANN USA

    $149.99
    Air Dryer WabcoThe Wabco 12 Volt Air Drier is an essential component for maintaining the integrity of your truck's air system. It removes moisture and contaminants to prevent damage to brakes and...
    955205
    SKU:
    955205
    Truck Class:
    Heavy Duty
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $149.99
    Qty in Cart: 0
    Price:
    $149.99
    Subtotal:
  • FREE SHIPPING OVER $249
    Hi-Temp Silicone Gasket Maker 3 oz. - Red

    Hi-Temp Silicone Gasket Maker 3 oz. - Red

    AFTERMARKET

    $17.68
    3 Ounce Tube Red Silicone Hi-Temp RTV Gasket MakerAre you working on a project requiring gaskets? 4 State Trucks stocks Master red high temperature RTV silicone Hi-Temp gasket makers for gasket...
    81160
    SKU:
    81160
    Truck Class:
    Universal
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    Ready To Ship:
    Yes
    $17.68
    Qty in Cart: 0
    Price:
    $17.68
    Subtotal:
  • MV3 Air Control Valve Dash Mounted Trailer Trip Pressure

    MV3 Air Control Valve Dash Mounted Trailer Trip Pressure

    AUTOMANN USA

    $205.99
    Air Valve MV3 Dash Control ModulesThe MV3 Air Control Valve Dash Mounted Trailer Trip Pressure provides superior trailer brake performance with reliable, dash-mounted control. Designed with angled...
    802804
    SKU:
    802804
    Length Options:
    1 Inch
    Truck Class:
    Heavy Duty
    Width Options:
    6 Inch
    Make:
    Universal Items
    Product Type:
    Air, Electrical, & Safety
    $205.99
    Qty in Cart: 0
    Price:
    $205.99
    Subtotal:
  • FREE SHIPPING OVER $249
    Dash-Mounted MV3 Air Control Valve With 2 Delivery, 1 Exhaust, 2 Supply Ports - 2.23 X 5.48 Inch Mounting Hole Spacing

    Dash-Mounted MV3 Air Control Valve With 2 Delivery, 1 Exhaust, 2 Supply Ports - 2.23 X 5.48 Inch Mounting Hole Spacing

    AUTOMANN USA

    $205.99
    MV3 Air Control Valve - Replaces BW801631, BW5013293, 745-801631, BEN801631, S-21729, 801631BXW & 5013294The Dash-Mounted MV3 Air Control Valve is a high-quality solution for managing your truck's...
    801631
    SKU:
    801631
    Truck Class:
    Heavy Duty
    Product Type:
    Interior
    $205.99
    Qty in Cart: 0
    Price:
    $205.99
    Subtotal:
  • FREE SHIPPING
    Dash-Mounted MV3 Air Control Valve With 2 Delivery, 1 Exhaust, 2 Supply Ports

    Dash-Mounted MV3 Air Control Valve With 2 Delivery, 1 Exhaust, 2 Supply Ports

    OPP - ORIGINAL PARTS PROGRAM

    $308.99
    MV3 Air Control Valve - Replaces BW801360, 745-801360, BEN801360, ZAC801360, S-23997, 801360BXW & 5009234* High Quality MV3 Air Control Valve* Dash Mounted* 2 Delivery Ports 90 Degrees Plastic...
    801360
    SKU:
    801360
    Color:
    Black
    Truck Class:
    Heavy Duty
    Material Options:
    Plastic/Poly
    Product Type:
    Interior
    $308.99
    Qty in Cart: 0
    Price:
    $308.99
    Subtotal:
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Adding your products to cart

Semi Truck Gladhands & Air Connections

A semi truck gladhand is the critical connection point between your tractor air lines and the trailer’s air-brake system. These heavy-duty couplers lock together with a rubber seal to hold air pressure securely. Our inventory helps you restore and replace your existing gladhand configuration when it’s cracked, leaking, corroded, or damaged. Semi Truck Gladhand Replacements: Replace worn or damaged tractor-trailer air couplers to restore a tight, reliable air connection. Service Gladhands: Blue service gladhands carry control air used to apply the trailer brakes during normal braking. Emergency Gladhands: Red emergency gladhands supply constant air pressure to the trailer and keep the emergency spring brakes released while driving. Gladhand Seals and Replacement Parts: Replace cracked, flattened, hardened, or leaking seals when the gladhand body and locking tabs remain in good condition. Air Lines with Gladhands: Find 2-in-1, 3-in-1, ABS, and power air lines to replace chafed, cracked, stretched, or worn tractor-trailer connections.

Signs of a Leaking Gladhand

Replace or inspect the gladhand when you notice hissing, air-pressure loss, frequent compressor cycling, slow air recovery, visible seal damage, or air leaking at the tractor-trailer connection.

Gladhand Seals vs. Complete Couplers

Replace the rubber seal when the coupler body is solid but the gasket is worn, cracked, flattened, or leaking. Replace the complete gladhand when the body, locking tabs, threads, or sealing surface is damaged or badly corroded.

Individual Gladhands vs. Complete Air-Line Assemblies

Individual gladhands make sense when your hoses remain in good condition and only the coupler needs replacement. Complete air-line assemblies replace the hoses and connections together. Choose them when lines are cracked, weathered, stretched, damaged, or due for replacement.

Air Brake Valves & Controls

We stock tractor-trailer air-brake protection valves, quick-release valves, emergency relay valves, and MV3 dash valves. Replace worn PP5 and PPDC control valves, trailer brake valves, and related spring brake components to restore proper air-brake control.

Air System Maintenance & Repair Parts

Maintain and repair your air system with air dryers, air solenoid valves, air hoses, fittings, and air tank hardware. Emergency air-brake and in-cab air-line repair kits also help address damaged lines and fittings during roadside repairs.

Trailer ABS & Electrical Connections

Keep tractor-trailer air and electrical connections organized with ABS cables, 7-way electrical cords, wrapped hose assemblies, air-line boxes, and pogo sticks. Replace worn or damaged connection hardware to protect air lines, power cords, and ABS wiring from dragging, chafing, and road damage.

Frequently Asked Questions About Semi-Truck Safety, Air & Electrical

What air pressure switches and valves are compatible with my specific truck model?

Compatibility depends on your truck's make, model, and year. Most Freightliner Cascadia models (2008-2023) use standard 1/4" NPT air pressure switches rated at 90-120 PSI. Peterbilt 579/389 models typically require 1/8" NPT connections. Kenworth T680/W900 models often use proprietary valve configurations. Always check your truck's service manual for exact specifications, or contact our technical support team with your OEM for precise matching.

How difficult is it to install safety lighting and electrical components myself?

Installation difficulty varies by component. LED marker lights and basic warning lights typically require 30-60 minutes with basic tools and can be DIY-installed by following color-coded wiring (white=ground, black=power). Air horns and pressure gauges require air line connections and may need professional installation to avoid leaks. Complex items like backup cameras or multi-circuit lighting systems often require 2-4 hours and intermediate electrical knowledge. We provide detailed installation guides with each product, and most customers report successful DIY installation for basic components.

What's the actual lifespan of LED safety lights versus traditional bulbs in real-world conditions?

Based on customer feedback and warranty data, quality LED safety lights last 30,000-50,000 hours of operation, which translates to 5-8 years of typical commercial use. Traditional incandescent bulbs average 1,000-2,000 hours (6-12 months). LEDs handle vibration better and maintain brightness longer. However, cheaper LED units may fail within 1-2 years due to poor heat dissipation or inadequate weatherproofing. We recommend DOT-certified LEDs with aluminum housings and IP67 or higher waterproof ratings for maximum longevity.

Which air brake components fail most frequently and what are the warning signs?

The most common failures occur in air dryers (every 2-3 years), pressure protection valves (3-4 years), and gladhand seals (annually). Warning signs include: air dryer constantly purging or not purging at all, slow air pressure build-up taking over 3 minutes to reach 90 PSI, air leaks audible when brakes are released, and moisture in air tanks. Quick-release valves often stick in winter conditions. Regular maintenance with quality replacement parts can extend component life by 30-50%.

What gauge and type of wiring should I use for adding auxiliary lights and accessories?

Wire gauge depends on the accessory's amperage draw and cable run length. For LED marker lights (0.5-2 amps), use 18-16 AWG wire for runs under 15 feet. Work lights and fog lights (3-10 amps) require 14-12 AWG wire. High-powered LED light bars (15-30 amps) need 10 AWG wire with inline fuses. Always use automotive-grade stranded copper wire with SAE J1128 rating for flexibility and heat resistance. Install proper fuses or circuit breakers rated at 125% of the accessory's amp draw. Avoid household solid-core wire as it becomes brittle and cracks from vibration.


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