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Optronics 4-Way/5-Way Flat Trailer Harness Plug Protector

Optronics 4-Way/5-Way Flat Trailer Harness Plug Protector

Item # ACP5B
Our Price: $9.15
Accessories and Parts
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Shipping Weight: 0.02 lbs
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Optronics Accessories and Parts - ACP5B
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Safeguard your trailer wire connectors against moisture, dust, and corrosion with this plug protector. Secures to trailer to protect harness from impact and abrasion. Fits 4-way and 5-way flat connections. Hardware not included. 1-800-940-8924 to order Optronics accessories and parts part number ACP5B or order online at Free expert support on all Optronics products. Great prices and Fastest Shipping for Optronics 4-Way/5-Way Flat Trailer Harness Plug Protector. Accessories and Parts reviews from real customers.
  • All Info
  • Reviews (81)
  • Q & A (0)
  • Videos (1)
  • Photos
  • Why etrailer?

Optronics Accessories and Parts - ACP5B

  • Trailer Wiring
  • Wire Protection
  • Connector Covers
  • 4 Flat
  • 5 Flat
  • Optronics

Safeguard your trailer wire connectors against moisture, dust, and corrosion with this plug protector. Secures to trailer to protect harness from impact and abrasion. Fits 4-way and 5-way flat connections. Hardware not included.


  • 4-Way/5-Way flat plug protector safeguards your trailer wire connectors against moisture, dust, and corrosion
  • Secures to trailer to protect harness from impact and abrasion
  • Surface mount with single screw - hardware not included


  • Dimensions: 1-1/2" wide x 1-1/4" tall x 1/2" thick
  • 3-Year warranty

ACP5B Connect-to-Protect 4-Flat/5-Flat Trailer Wire Connector Dust Cover

California residents: click here

Video of Optronics 4-Way/5-Way Flat Trailer Harness Plug Protector

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Optronics Trailer Plug Covers - 4 Flat Cover - ACP5B Review

Today, we are going to take a look at the Optronics 4 way and 5 way Flat Trailer Harness Plug Protector. Now this is going to be a quick and easy way to protect the four or five pole wiring on your trailer. A lot of times those can get banged around especially if you are using them for a long time or they're in frequent use.This is just going to go over our bare terminals on that trailer end wiring and then it's also going to have a small plastic post that is going to fit into the open port for our ground on our wiring. So here we have a four pole. This also, again, works with five pole, it just has the extra terminal on the one side which our plug is built for and it just matches right up. Fits inside there, fits really snug and then you would just have this attached to say the coupler on your trailer or maybe the tongue, just anywhere where you would want this wiring to be secured and out of the way.This is going to keep any debris from building up inside those terminals on your wiring or any water build up or anything like that.

And it's going to keep that wiring from getting corroded or kind of gunked up and it's also going to keep it from getting banged around on the ground or impacted with anything. It's just going to keep it nice and up and out of the way.Now this does not come with any hardware to get that attached so you will have to pick up a self tapping screw or whatever hardware you'd like to use, maybe a nut and a bolt but you will have to provide that on you own. The mounting hole is going to be about 3/16th of an inch in diameter, overall the connector is going to be about an inch and a half wide by about an inch and a quarter tall and at the widest point where it sort of bows out for our mounting location, that's going to be about half an inch. So it's really going to be about the same size as the connector on your wiring. It's pretty comparable there.All in all, it's just going to be quick and easy way to improve the longevity of your wiring on your trailer and keep everything working as it should.

It's not a bad idea to maybe put a little bit of dialectic grease in those terminals so that it'll keep the grease on your plug as well. If you don't have any of that, we do sell dialectic grease here at if you want to pick some up.And that's going to do it for our look at the Optronics 4 and 5 way Flat Trailer Harness Plug Protector.

Customer Satisfaction Score:

Customer Reviews

Optronics 4-Way/5-Way Flat Trailer Harness Plug Protector - ACP5B

Average Customer Rating:  4.8 out of 5 stars   (81 Customer Reviews)

Safeguard your trailer wire connectors against moisture, dust, and corrosion with this plug protector. Secures to trailer to protect harness from impact and abrasion. Fits 4-way and 5-way flat connections. Hardware not included.


The product seems to be well made. It is fit for purpose.

Attached to trailer's draw bar with a #10 x 1 inch, pan head self-tapping screw (with blue thread-locker for extra-robust fastening).


Does what it is supposed to: protect exposed plug from the elements. Simple, effective. Would have rated it “Excellent “ except for the high price. Similar caps for the vehicle side are a fraction of the price.


I have used e-trailer for years for all my trailer needs. They always provide quality products with fast shipping. Will use them again the next time i need something for one of my trailers.


Was looking a long time to find this dust cover for my trailer harness, found it on your web site, thanks


Keep things neat and organized. Exactly what I was looking for.

Still going strong, glad I purchased it.
Alan - 11/04/2021


This little thing will keep your light plug up and out of the dirt or keep critters from chewing at a dangling plug.


The only place I could find a 5 pin flat cover. It fits nicely.


Appears as described. I haven’t mounted to trailer yet but I expect the plug protector to do the job.


As expected


A great company to deal with. Quality products and excellent turnaround for delivery. I am very pleased with the product line as well. 5 star


Works great


Great product to keep the dirt out of your trailer wiring when not in use


Product as advertised, fast delivery even with standard delivery option.


As advertised. Plug fits in nice and snug. Should be a nice cover to shield from weather and keep from dangling.


Working great to keep the connector off the ground and clean.


First time I have used a product like this, love it, keeps my trailer connection good and clean.


Its a fine product, I wish they had separate 4 plug and five plug protectors because My plug has a built on partial cover rather than 4 bare prongs like in the vide so I have to modify my plug a bit to work with this which if it were specific to 4 way I would not have that problem. Price is a bit steep as this comes with no mounting hardware. Its understandable that it has no hardware because everyone has a different situation and preference. I use 12-24 stainless nut and bolt to attach to my trailer in a spot that is out of the sun etc.


As always, excellent service and products! Never had a bad ordering experience with etrailer and I highly recommend them for both friendly and prompt service and quality of products sold. They are my go to company for trailer needs!


keep the connector plugs clean. i also used a small amount of WD-40 to help keep the rust down over the winter


Raised area around mount hole provides clearance for plug from mounting surface. It doesn't retain the plug very tightly, and only by the pins. It is for use while trailer is parked. The plug won't just fall out, but brushing the hanging pigtail can pull it. Be sure to seat the plug completely.


Attached this to my trailer and keeps plug protected and up off the ground.


should come standard on all trailers excellent product.


item was a perfect fit thanks


Product was great, only thing was the hubcaps that came with were too big but they provided the right size free of charge


Works great.

Show More Reviews

See what our Experts say about this Optronics Accessories and Parts

  • Dust Cover For 5 Way Trailer Connector To Protect From The Elements
    We do sell a 5 pole trailer connector cover # ACP5B. This will work on vehicle end or trailer end and is a great way to prevent corrosion and damage to your plugs.
    view full answer...
  • Trailer Side 5-pole Wiring Harness Weather Cover
    It too me awhile to find one. I found Optronics # ACP5B Weather Cover. Not only does it keep your plug out of the weather - but keeps it off the ground as well. I also recommend that you use the Edelmann # 11755 dielectric grease. Just dab a little bit on all the connection points. This will go a long way towards keeping those connectors free of weather, dirt, and corrosion. Once you get corrosion in one of the female connectors it is nearly impossible to get it cleaned out.
    view full answer...

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Info for this part was:

Employee Kathleen M
Installed by:
Kathleen M
Employee Ronnie R
Updated by:
Ronnie R
Employee Daron K
Edited by:
Daron K
Employee Brian T
Written by:
Brian T

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