Problem with outside lights

What's a 10 amp blade fuse? Can I just tell the guy at radio shack and he'll hand it to me?

kaulana wrote:

CaptPicky wrote:
Go buy you a multi-tester at Wally World or Radio Shack. Start at the beginning. Make sure your wiring connector on your truck is working. Test each connection. Then start working your way down the line towards your trailer. There probably is a broken connection somewhere along the line.

I got a tester and started at the tv connection. With the lights ON on the truck, two pins read between 50-60 volts and the rest were zero. So this must be a problem with the fuse on the TV then? I found the fuse box near the engine, and found which two fuses control the trailer hookup, but not sure what to do next.

Do I replace these? Should I just take my truck in to the shop? (I tried to get the fuse out by tugging lightly, but it didn't budge and I didn't want to break anything)

Thanks again

OK,
I guess a little tutorial on meter use is in order. BTW, post back with a description of your meter or a link to what it is, it makes it easier to share what is going on.

With the red lead of the meter connected into the V,ohm,mA hole and the black lead connected into the COM hole, you place the business end of the red lead into your vehicle's 7 pin receptacle in the "green" pin slot depicted in the diagram. The black business end from your meter can either be in the "ground/white" pin slot of the receptacle or anywhere on the vehicle that has a good, bare metal connection to the frame, and hence, also to ground. With the vehicle's headlight switch turned on, your meter (with selection set to DCV) should read 12V->12.6V.
If you get no voltage reading, there is no power to the vehicle's trailer receptacle and you will have to check fuses, first, to see if one or more are blown. To check a fuse, remove the fuse, set your meter to one of the Ohm settings, place one meter lead on one leg of the fuse and the other meter lead on the other leg of the fuse. Your meter should read (0.00) if the fuse is good. If it is bad, you will see some value or infinite. This use is called checking for circuit continuity.
If fuses check to be good, it may be that you have an "open", a wire that is parted or termination that is not connected. A good place to look for this is on the back of the vehicle's trailer receptacle. Sometimes, road debris can fly off roadway and part a wire at the back of the receptacle.
Try the voltage readings and fuse viability and we can help from there.

50-60 volts?
Should be reading around 12 volts.
Sounds like wrong scale on the meter.
Blade fuses get hard to pull.
What kind of truck?
There could be more then one fuse per function.

kaulana wrote:

CaptPicky wrote:
Go buy you a multi-tester at Wally World or Radio Shack. Start at the beginning. Make sure your wiring connector on your truck is working. Test each connection. Then start working your way down the line towards your trailer. There probably is a broken connection somewhere along the line.

I got a tester and started at the tv connection. With the lights ON on the truck, two pins read between 50-60 volts and the rest were zero. So this must be a problem with the fuse on the TV then? I found the fuse box near the engine, and found which two fuses control the trailer hookup, but not sure what to do next.

Do I replace these? Should I just take my truck in to the shop? (I tried to get the fuse out by tugging lightly, but it didn't budge and I didn't want to break anything)

Thanks again

What kind of truck is it?

Are they blade fuses or cartridge fuses (looks like this)?

Either way, they just pull out. Sometimes, they can be a little stubborn. You should be able to see if a cartridge fuse is blown.

Simple test you can do on the trailer. Look at the pictures above (7 blade connector, trailer side). With trailer battery connected, use a 10 amp blade fuse to connect the top two terminals on the trailer umbilical cord. If trailer wiring is good, your running lights will come on. If they light up, your problem is in the truck. Fuses, most likely.

Trailer tail, brake, and running lights get their power from the truck. Running lights are on a seperate circuit from brake / tail lights.

westend wrote:

If you have a Standard 7 pin RV connector, check the vehicle-side pin "green" for power when the headlight switch is turned on.
You can do this with your new handheld multimeter that you've purchased. BTW, Harbor Freight sells a handy, small multimeter for around $4. If you are not near a Harbor FReight store, most hardware and big box stores also sell the multimeters. It is something that every owner of an RV should have onboard.
Good luck with your lights.

That photo is very helpful!! The only two that are showing any reading are the top right and bottom right (taillights and ground). The rest are zero. Its 7 blade configuration.

:?

CaptPicky wrote:
Go buy you a multi-tester at Wally World or Radio Shack. Start at the beginning. Make sure your wiring connector on your truck is working. Test each connection. Then start working your way down the line towards your trailer. There probably is a broken connection somewhere along the line.

I got a tester and started at the tv connection. With the lights ON on the truck, two pins read between 50-60 volts and the rest were zero. So this must be a problem with the fuse on the TV then? I found the fuse box near the engine, and found which two fuses control the trailer hookup, but not sure what to do next.

Do I replace these? Should I just take my truck in to the shop? (I tried to get the fuse out by tugging lightly, but it didn't budge and I didn't want to break anything)

Thanks again

Thanks everyone for the help! I got caught up with the big game yesterday so I haven't had a chance to try those ideas out. I will try after work and post the results.

Thanks again!!

If you have a Standard 7 pin RV connector, check the vehicle-side pin "green" for power when the headlight switch is turned on.
You can do this with your new handheld multimeter that you've purchased. BTW, Harbor Freight sells a handy, small multimeter for around $4. If you are not near a Harbor FReight store, most hardware and big box stores also sell the multimeters. It is something that every owner of an RV should have onboard.
Good luck with your lights.

Most likely a blown fuse / relay in the truck. Check your owners manual for location of trailering fuses / relays. Probably in a fuse box in engine compartment.

There are seperate fuses / relays for running lights, turn signals, charging circuit, etc.

I've had same problem with 06 Nissan Titan and 08 Ford F250. The Nissan was a 10 amp fuse, and, the Ford was a 20 amp relay. Both were located in a box under the hood.

Check the bulbs. Brake lights use different filaments than running lights.