Trailer wiring harness brake fuse? - Honda Pilot - Honda Pilot Forums

Register Home Forums Active Topics Insurance Photo Gallery Garage Search Today's Posts Mark Forums Read Auto Escrow
Piloteers.org is the premier Honda Pilot Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Rate Thread
Old 03-27-2013, 11:21 AM   #1 (permalink)
Registered User
 
Join Date: Feb 2004
Location: O
Posts: 154
Feedback Score: 0 reviews
Default Trailer wiring harness brake fuse?

My driver's side brake light on my boat trailer just went out. I replaced it with another brand new LED light and it still doesn't work. I've verified the brake light itself is not getting any power, so now I'm looking at the truck. Where exactly is the trailer wiring harness fuse located? I have the OEM towing package that came with the truck when I bought it new. Is there a fuse in the rear left panel compartment? Or are their trailer harness fuses located in the subfuse box under the hood in the engine compartment?
bman5150 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 03-27-2013, 12:52 PM   #2 (permalink)
Registered User
 
Join Date: Jan 2013
Location: Alabama
Posts: 27
Feedback Score: 0 reviews
Default

If the right side still works and the left doesn't then you have a wiring problem not a fuse problem. If it were a fuse then the right side wouldn't work as well since both brake lights are typically on the same fuse. Look for a broken wire or exposed wires somewhere on the trailer. If you're running a 4 wire connector then the wires will tie together at the connector or somewhere on the trailer. If you're running a 7 pin connector then there are separate left and right pins but it just depends on who originally wired the trailer. Start by checking the pins on the vehicle for power when you hit the brake. If you have power there then you know its somewhere between the connector and the lights.

Last edited by spray004; 03-27-2013 at 01:00 PM.
spray004 is offline   Reply With Quote
Old 03-27-2013, 01:25 PM   #3 (permalink)
Registered User
 
Join Date: Feb 2004
Location: O
Posts: 154
Feedback Score: 0 reviews
Default

Quote:
Originally Posted by spray004 View Post
If the right side still works and the left doesn't then you have a wiring problem not a fuse problem. If it were a fuse then the right side wouldn't work as well since both brake lights are typically on the same fuse. Look for a broken wire or exposed wires somewhere on the trailer. If you're running a 4 wire connector then the wires will tie together at the connector or somewhere on the trailer. If you're running a 7 pin connector then there are separate left and right pins but it just depends on who originally wired the trailer. Start by checking the pins on the vehicle for power when you hit the brake. If you have power there then you know its somewhere between the connector and the lights.
Thanks spray004. You are right; I just looked over my Pilot owner's manual and didn't see any fuse listed specifically for the "driver's side" brake lamp. The truck's lights all work properly. Furthermore, there are only 3 trailer harness-specific fuses I can see - none appear specific to the stop lamps.

Usually these kind of things end up being pretty simple, so I'm going to go back and check my trailer's harness adapter. The trailer came with a straight 7-pin harness and I purchased an adapter for direct plug into the Pilot's harness. My guess is I might have an issue with the adapter or maybe even the trailer's harness. Possibly corrosion. I'm hoping it's not a wire short...major PITA to locate these when a good portion of the wiring is inside the trailer frame rails.

Wouldn't it be odd for me to have a short though specific to one single light on the trailer and to NOT be blowing any fuses? This is another reason I'm checking the 7-straight pin to oval adapter first.

This is helpful - thanks for your input.
bman5150 is offline   Reply With Quote
Old 03-27-2013, 01:43 PM   #4 (permalink)
Registered User
 
Join Date: Jan 2013
Location: Alabama
Posts: 27
Feedback Score: 0 reviews
Default

Quote:
Originally Posted by bman5150 View Post
Thanks spray004. You are right; I just looked over my Pilot owner's manual and didn't see any fuse listed specifically for the "driver's side" brake lamp. The truck's lights all work properly. Furthermore, there are only 3 trailer harness-specific fuses I can see - none appear specific to the stop lamps.

Usually these kind of things end up being pretty simple, so I'm going to go back and check my trailer's harness adapter. The trailer came with a straight 7-pin harness and I purchased an adapter for direct plug into the Pilot's harness. My guess is I might have an issue with the adapter or maybe even the trailer's harness. Possibly corrosion. I'm hoping it's not a wire short...major PITA to locate these when a good portion of the wiring is inside the trailer frame rails.

Wouldn't it be odd for me to have a short though specific to one single light on the trailer and to NOT be blowing any fuses? This is another reason I'm checking the 7-straight pin to oval adapter first.

This is helpful - thanks for your input.
I've never had any good luck with the 7 pin to 4 pin adapters for whatever reason. Are the frame rails C channels or tube rails? If they're just C channels you can crawl under the trailer and follow the wires usually and look for issues. It is uncommon for an exposed wire not to blow a fuse when it grounds itself but can happen I suppose.
spray004 is offline   Reply With Quote
Old 03-27-2013, 02:41 PM   #5 (permalink)
Registered User
 
Join Date: Feb 2004
Location: O
Posts: 154
Feedback Score: 0 reviews
Default

Quote:
Originally Posted by spray004 View Post
I've never had any good luck with the 7 pin to 4 pin adapters for whatever reason. Are the frame rails C channels or tube rails? If they're just C channels you can crawl under the trailer and follow the wires usually and look for issues. It is uncommon for an exposed wire not to blow a fuse when it grounds itself but can happen I suppose.
My flat 5-pin trailer harness uses a round 7-pin adapter to plug into the truck. Looks something like this:

Adapter 7 Pole to 5 Pole Flat - Molded Optronics Wiring A75TB

The trailer is rectangular but tubular, with a few drain holes ever few feet or so. The more we discuss this the more I'm convinced it's just corrosion or an issue with the adaptor. Easy for me to check this so that's what I'll do.

Also forgot to mention - it's a 5-pin becasuse I have surge brakes on the trailer - the extra "pin" is to lock out the brakes when I put the truck into reverse for backing.

Last edited by bman5150; 03-27-2013 at 02:44 PM.
bman5150 is offline   Reply With Quote
Old 03-27-2013, 03:07 PM   #6 (permalink)
Registered User
 
RSQ Pilot's Avatar
 
Join Date: Aug 2008
Location: Central IL & Many Road Trips
Posts: 1,799
Garage
Feedback Score: 0 reviews
Default

Quote:
Originally Posted by bman5150 View Post
My flat 5-pin trailer harness uses a round 7-pin adapter to plug into the truck. Looks something like this:

Adapter 7 Pole to 5 Pole Flat - Molded Optronics Wiring A75TB

The trailer is rectangular but tubular, with a few drain holes ever few feet or so. The more we discuss this the more I'm convinced it's just corrosion or an issue with the adaptor. Easy for me to check this so that's what I'll do.

Also forgot to mention - it's a 5-pin becasuse I have surge brakes on the trailer - the extra "pin" is to lock out the brakes when I put the truck into reverse for backing.
Have you tried a voltage tester or test light for continuity in the wiring/connections from the Pilot through the adapters to the brake light/turn signal contacts in the taillight housing or a try a non-LED bulb?
__________________
2009 Pilot Touring RES 4wd Mocha Metallic; OEM Premium Running Boards, OEM cargo tray, Weathertech Floor Liners, H-9 LB mod, full size LTX spare w/alloy rim, AVS Bugflector II
2010 Honda CR-V EX-L AWD Taffeta White...OEM cargo tray, mudguards and WeathertTech floor liners; Blue Ox dinghy setup.
2007 Winne Aspect 26A; Ford V10 gas hog, Blue Ox dinghy setup.
RSQ Pilot is offline   Reply With Quote
Old 03-27-2013, 03:14 PM   #7 (permalink)
Registered User
 
Join Date: Feb 2004
Location: O
Posts: 154
Feedback Score: 0 reviews
Default

Quote:
Originally Posted by RSQ Pilot View Post
Have you tried a voltage tester or test light for continuity in the wiring/connections from the Pilot through the adapters to the brake light/turn signal contacts in the taillight housing or a try a non-LED bulb?

Will be testing those tonight or tomorrow.

I've tried standard and an LED stop lamp. Both work in the passenger side; both don't work on the driver's side.

I'll report back what I find.
bman5150 is offline   Reply With Quote
Old 04-01-2013, 01:06 PM   #8 (permalink)
Registered User
 
Join Date: Feb 2004
Location: O
Posts: 154
Feedback Score: 0 reviews
Default Update

I verified that the truck plug was working just fine using a multimeter. It turned out to be a bad adapter and/or 5 pin straight plug on the trailer. Replaced the adaptor and original 5 pin straight harness that came with the trailer with a new round 7 pin for a direct fit into the truck's harness reciever - problem fixed.

Thank god it wasn't some short in the trailer somewhere! Much easier fix!

Thanks for your guideance.
bman5150 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -4. The time now is 11:01 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.3.2
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
Copyright 2000 piloteers.org. All Rights Reserved.