How to test 4 pin on TV with multimeter

[Spaceace5150]

Hi all,

I picked up my pup today in hopes of getting it ready for camping season. Hitched up, and crossed my fingers but the trailer lights didn’t work.

My TV has a 4 pin connector with a 4 pin to 7 pin adapter to connect to the trailer. I am not getting power on the 7 pin (I have one of those testers). Now I’m working backwards and want to test the 4 pin. I don’t have a tester and can’t get one right now due to everything going on in the world.

how can I test the 4 pin on the tow vehicle with a multimeter? I haven’t been able to find good instructions yet.

thank you!

 

[Sjm9911]

Not going to lie, i didn't watch it. Plenty of stuff on you tube.

 

[Raycfe]

Set the meter to 20 VDC
Connect black meter lead to a clean bare metal part of the frame/hitch.
Turn on parking/taillights (be sure they are on, on tow vehicle) and connect the red meter lead to the terminal next to the bare uncovered one > should read 12 VAC+ on meter. If OK move the black meter lead from the frame to the uncovered terminal of the plug > should read 12 VDC+. The ground circuit (the uncovered terminal) and the running/taillight circuit are good.



Now turn the tow vehicle key on and test the last 2 terminals (turn signals) they will blink...Keep the black meter lead on the uncovered terminal.

 

[Anthony Hitchings]

its much easier to buy a plug in tester on Amazon (this said after years of usingmultimeters)

 

[nineoaks2004]

The plug in testers are available at Rural King too, I just bought two, one for my son and one for my tool box. I think the coast was about $5.00, work easier than a
multi-meter If nothing is working you might check the ground wire first, also if when head lights are on and a turn signal on the far side from your check then you probably have a loose or bad ground. It is really hard to test an electrical problem over the internet and without seeing the problem in person. Good Luck and I hope you get the problem fixed without and big problems.

 

[Spaceace5150]

Set the meter to 20 VDC
Connect black meter lead to a clean bare metal part of the frame/hitch.
Turn on parking/taillights (be sure they are on, on tow vehicle) and connect the red meter lead to the terminal next to the bare uncovered one > should read 12 VAC+ on meter. If OK move the black meter lead from the frame to the uncovered terminal of the plug > should read 12 VDC+. The ground circuit (the uncovered terminal) and the running/taillight circuit are good.

View attachment 59977

Now turn the tow vehicle key on and test the last 2 terminals (turn signals) they will blink...Keep the black meter lead on the uncovered terminal.

Thanks! I’ll try this when I’m able to get outside.

 

[Spaceace5150]

its much easier to buy a plug in tester on Amazon (this said after years of usingmultimeters)

its much easier to buy a plug in tester on Amazon (this said after years of usingmultimeters)

I agree... but the quickest amazon could get me a tester is in May. I didn’t want to wait that long so trying to figure it out with what I have.

 

[Wrenchgear]

Yes, as Raycfe has shown above, its all very easy. The bare uncovered terminal on the TV side is the ground. All the others are hot/live while lights in the vehicle are working. They are protected with rubber/plastic so they don't ground out in the trunk of the car and blow a fuse while driving around without a trailer on. Very easy to remember the order. I'm right handed, so I start a lot of sayings with the word 'right'. In this case it's, - right, left, tail, ground.

If there is a problem at the connector, but the lights on the vehicle work, obviously you need to follow the wiring back to their connection point and find where the break in the connection is.

If you get the connector of the TV working, and still show some whacky problems at the back of the trailer, try wiggling the connection of TV to trailer around a little bit. They sometimes form a little corrosion in there and make bad connections. It's easier than starting to tear everything apart if it may not be necessary.

 

[bheff]

I agree... but the quickest amazon could get me a tester is in May. I didn’t want to wait that long so trying to figure it out with what I have.

Try other places than Amazon. Autozone, Lowes, walmart all ship or deliver.

 

[neighbormike]

A simple test light will do... no dedicated tester or multi-meter needed.

 

[Spaceace5150]

Try other places than Amazon. Autozone, Lowes, walmart all ship or deliver.

Thanks for the tip! I was able to order from Home Depot with free two day shipping. Very convenient for a part that is less than $4.

 

[Spaceace5150]

Thank you all for the help with this! I am always learning so much from this forum.

I was able to troubleshoot and the 4-pin works, so it is my 4-pin to 7-pin connector that is the issue.

 

[Jawritch]

Did you get it sorted out? You can use the same voltmeter or test light to check the 7 pin side of your adapter aswell.

 

[Fless]

Keep in mind that some vehicles have separate fuses for the trailer connections. My Tahoe even has individual fuses for the trailer turn signals -- one for the right, and one for the left, independent from the truck's turn signal circuits. So even though the TV lights work, the trailer ones might not. YMMV
_

 

[Spaceace5150]

Did you get it sorted out? You can use the same voltmeter or test light to check the 7 pin side of your adapter aswell.

I think I have it figured out, there is an issue with my 7 pin adapter. I've actually ordered a replacement and am waiting for it to arrive.