Trailer light problem
Cargo Master
Joined: Oct 2015
Posts: 2,745
Likes: 72
From: West Virginia
I felt the same way about my P3. I did let my brother in law borrow it - six months ago! So he must feel the same way about it.
New User
Joined: Dec 2018
Posts: 4
Likes: 0
2012 F-250 Super duty
just replaced wiring harness with 4 prong flat plug and lights on my trailer and after finding no lights replaced #100 fuse that fixed the brake and turn signals but still have no running lights Tested the hole where it plugs to and it shows no power unless I press the brake and then it shows 2 volts. All other related fuses and relays have been checked and are all good. I'm thinking smashed or frayed wire or harness connection but not sure where to start looking. Any ideas ?
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
Since you've gone through all the swapping and staring exercises without getting anywhere, you're going to need to get serious.
So, SPECIFIC questions that require SPECIFIC answers:
Did you verify that F26 is actually passing power? (meter, test lamp, etc)
Did you verify that that the trailer tow park relay is energizing when the headlight switch is in PARK or HEADLIGHT?
So, SPECIFIC questions that require SPECIFIC answers:
Did you verify that F26 is actually passing power? (meter, test lamp, etc)
Did you verify that that the trailer tow park relay is energizing when the headlight switch is in PARK or HEADLIGHT?
New User
Joined: Dec 2018
Posts: 4
Likes: 0
No I didn’t because when I swapped the wiper really for it there was nothing wrong with it the wipers worked just fine and the parking light still didn’t work with the wiper really in
Since you've gone through all the swapping and staring exercises without getting anywhere, you're going to need to get serious.
So, SPECIFIC questions that require SPECIFIC answers:
Did you verify that F26 is actually passing power? (meter, test lamp, etc)
Did you verify that that the trailer tow park relay is energizing when the headlight switch is in PARK or HEADLIGHT?
So, SPECIFIC questions that require SPECIFIC answers:
Did you verify that F26 is actually passing power? (meter, test lamp, etc)
Did you verify that that the trailer tow park relay is energizing when the headlight switch is in PARK or HEADLIGHT?
New User
Joined: Dec 2018
Posts: 4
Likes: 0
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Cargo Master
Joined: Oct 2015
Posts: 2,745
Likes: 72
From: West Virginia
When you look at the top of a blade fuse you can see some tiny little bits of exposed metal. Make sure your volt meter lead has a small enough point to fit into the opening, place the red probe on one of the metal bits of the fuse and the black probe on a good metal bolt (or similar) on the engine (alternator mount works well). Energize the circuit (attempt to make it work) and look for 12 volts or so on the meter.
If voltage is present, then the problem is somewhere between the fuse and the light bulbs.
If voltage is not present, then you need to move to the next point in the circuit between that fuse and the battery that you can test.
Keep going (either direction) until you find your 12 volts. Keep going until you find the open and repair it.
New User
Joined: Nov 2017
Posts: 16
Likes: 0
From: Gillespie Co. Tex.
Well, yes and no. You need fire in 26 on two of the sockets: The power you're passing, which will always be on, and the trigger (or pull) circuit which will be hot when the relay is supposed to be pulled in. If 26 doesn't have fire at one of the relay sockets when the light switch is off, and at two sockets when the light switch is on, then you have some problem "upstream" of the relay hole. If it is showing fire at one, then two, with light switch off then on, the the relay is probably doing its job (since it's making the wipers work when it's in that hole) and your problem is somewhere "downstream".
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Bigpapa346
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Apr 25, 2012 08:59 AM