Great comment. Alligator clip at least for negative and then test around with the positive.

Glad it helped you Jeremy!

I just installed a brake controller on a neighbors truck. Since he didn’t purchase the vehicle with a tow package, that hot wire was not wired to the rear of the vehicle. And the fuse box in the engine bay also had the brake controller wiring not connected and tucked / stowed away.

Thanks!

Check your fuses

Glad it helped!

lol, me too!

Logical mistake. :)

Yes. Black probe stays on negative. If you look at the diagram in my video, putting the red probe on the various pins should display 12-14 volts when the brakes are on, running lights are on, blinkers are on, etc.

The Aux pin is always hot delivering a constant 12V to the RV when plugged in. This will supplement the RV's existing battery(s) or power the RV's 12V devices if the RV's battery(s) are disconnected.

You're right Leigh, sorry about that! I put the diagram up to help make it more clear. Just know that whatever function I'm checking, the black probe is always on "-12VDC/Ground" and the red probe is on the function's corresponding pin according to the diagram.

Bruh he said he put it on the negative and positive. He also Eben put up the diagram. Everything he put the price he says what he put it on. So you just gotta see the diagram to probe. This is easy. Just listen and follow.

He explained exactly where he was putting them, and a quick Google search tells you exactly what pins he is touching.

Thank god someone said it!!

You're right WCO. I didn't have footage that showed the trailer's 7 pin connector wiring had separated from the pins and that was the reason I replaced the trailer's cable. After testing the Telluride's 7 pin connector and finding that it was good, I knew the problem was with the trailer wiring. In my case, the trailer's connector and connector wiring was old and had been serviced in the past. I took apart the connector and saw wiring that had disconnected from the connector's pins.

apparently new vehicles with the newer electronics built in won't send power to the pin unless it detects a load. so you won't get a reading on the meter.

You're looking to measure 12 VDC so set your meter to "Volts DC"

You pretty much ruled out the tow vehicle, but if you want to be certain, just hook 12v directly to the trailer pins to see if the running lights work. If not, you know the problem is with the 12+ wire to the lights, or a bad ground at the lights. You could check continuity at both ends to see if there's a break or pinched wire on the 12+ side or bad ground connection at the 12-.

bad switch, or a short

If the trailer is new, the most likely culprit is the tow vehicle wiring or connector. Just test the pinouts and see what you get.

If it's just the right side it's probably a bad wire.

@@PIFDIY i figured it out there are 2 extra 10 amp fuses for towing lights/turn signals under the drivers side steering wheel, behind the OBD2 reader.(At least for my vehicle) One of them was bad. Replaced it and it worked! I saw another KZfaq video i will post link to it Incase anyone else sees this comment. Thank you for the video btw 🙌🏽

@@PIFDIY kzfaq.info/get/bejne/jd9jp6iG3tvMiXU.html

@@eirod Ok Ivan, having two separate fuses (one for each side) explains how one side could be bad while the other good. Unusual set up I believe, glad you figured it out!

ok i suppose "NOTHING" Specifically means NO VOLTAGE Ok do this (now keep in mind i'm in Sydney and you're probably in america) it's still ok though the concept is the same. you either have a round connector or flat connector (we use the flat one) the connectors are either 5 pin or 7 Pin we use the 5 pin version because we don't have brakes on our box trailers In any case, this is just Ohm's law, it's not complex , IT'S JUST A CIRCUIT AT THE END OF THE DAY and try to see it as such 1. LET'S START WITH BRAKE LIGHTS (Brakes on the car, not on the trailer) - Is the key in the ignition ? - Do you have the car turned onto ACCESSORIES or either ENGINE ON ? if you're in Position 1 (The electricals are not on, it won't work) Basically we are confirming that the brake lights on the car work If you think it's all connected - Get someone to stand at the back of the car, Press the Brake and confirm that the brake lights come on (Do this without the trailer connected) if they don't come on (that's why the trailer lights are not coming on) Check fuse for the brake lights, Check wiring - Now connect your trailer Do the same again, IF THE CAR BRAKE LIGHTS DO NOT COME ON - You have a SHORT CIRCUIT from the connector to the back of the trailer somewhere in the wiring IF THE CAR BRAKE LIGHTS COME ON BUT THE TRAILER LIGHTS DO NOT - You have an OPEN CIRCUIT (Broken Wire somewhere) NOW ON THAT KNOWLEDGE with the trailer unplugged, CHECK BOTH INDICTORS AS WORKING CHECK IF THE NUMBER PLATE LIGHT LIGHTS UP (when either the car is ON or Key in the ACCESSORIES POSITION if this is all good, the problem is with your trailer (first and foremost) NOW.. IF THIS... "Have power with pos and neg. But get nothing on any ither pin. What can cause that ?" MEANS, You have No Power on any other pin AT THE TOE BAR CONNECTOR ON THE CAR........ it means the mechanic hasn't wired it correctly. if he has you should get all your voltages at the car connector if you're talking about ... at the other end then the trailer is the problem THE MOST COMMON CAUSE OF NOT GETTING VOLTAGE IS OPEN CIRCUIT or SHORT CIRCUIT Open Means... A Wire is broken somewhere. Short Means... 2 Wires that a not supposed to be touching are touching ALSO ARE YOU TESTING IT CORRECTLY ? ARE YOU SURE Your RED Probe goes onto a POSITIVE Pin Your BLACK Probe goes onto a NEGATIVE Pin or Ground If you test from a Positive to a Positive IT WILL READ 0V even though there is 12V Present Example.. If you put your probe on the RED Wire (the Brake Light) and then on the BLACK Wire (which is actually the Positive as well) YOU WILL GET A READING OF 0V or you will blow something The White Wire is Negative ALL THE WHITES SHOULD BE CONNECTED TOGETHER if they are not, you have an open circuit on multiple circuits which is .. what you are describing so let's say you have INDICATOR BRAKE LIGHT NUMBER PLATE LIGHT (this is 3 circuits, but you have to count the white wire from the car) so, this means there should be 4 Whites connected together You might find that 2 whites are connected and the other 2 are not THAT WOULD EXPLAIN WHAT YOU'RE GETTING Because if the common ground is not connected, you have an Open Circuit Does that help

I don't believe so. If you apply the brakes, the brake controller will put out a voltage on the pin. A proportional brake controller will vary the voltage on the pin depending on pedal pressure but voltage would be 0 when brake is not used.

@@PIFDIY thank you

kzfaq.info/get/bejne/bqyooaio0tOlnnU.html This will always be the same voltage as the car battery.

Elizabeth, refer to the diagram in the upper right in my video. Put the black probe on the "-12VDC Ground" and the red probe on any of the circuits that you are testing. For example, to test the trailer running lights, put the black probe on "-12VDC Ground" and the red probe on "Running Lights" according to the diagram. When testing, make sure that your multimeter is set to measure DC volts and the ignition is on. For things like brakes lights, you may need someone in the car to apply the brakes.

@@PIFDIY Thank you so much for this information. I rely on these videos to make sure I'm doing it right.

*you

To test a 7-pin trailer connection with a multimeter, follow these steps: 1. **Set Up the Multimeter**: Turn on your multimeter and set it to measure voltage (DC voltage). 2. **Identify the Pins**: Refer to a 7-pin trailer connector diagram to identify the pins: - Pin 1: Ground (usually white) - Pin 2: Tail/Marker lights (usually brown) - Pin 3: Left turn/brake light (usually yellow) - Pin 4: Right turn/brake light (usually green) - Pin 5: Backup lights (usually blue) - Pin 6: Brake controller output (usually red or black) - Pin 7: 12V power supply (usually black or red) 3. **Connect the Multimeter**: - **Ground**: Place the black (negative) probe on the ground pin (Pin 1). - **Power Supply**: Place the red (positive) probe on the 12V power pin (Pin 7). You should read 12V or higher if the vehicle’s ignition is on. 4. **Test Each Pin**: - **Tail/Marker Lights**: Turn on the vehicle’s lights and place the red probe on the tail/marker light pin (Pin 2). You should read voltage. - **Left Turn/Brake Light**: Activate the left turn signal and place the red probe on the left turn/brake light pin (Pin 3). You should see the voltage pulsing with the turn signal. Press the brake pedal and check for a constant voltage. - **Right Turn/Brake Light**: Activate the right turn signal and place the red probe on the right turn/brake light pin (Pin 4). You should see the voltage pulsing with the turn signal. Press the brake pedal and check for a constant voltage. - **Backup Lights**: Place the vehicle in reverse and place the red probe on the backup light pin (Pin 5). You should read voltage. - **Brake Controller Output**: If you have a brake controller, place the red probe on the brake controller output pin (Pin 6) and activate the controller to check for voltage. 5. **Check for Ground**: Switch the multimeter to continuity mode. Place one probe on the ground pin (Pin 1) and the other on a known ground point on the vehicle chassis. You should hear a beep or see a zero reading, indicating continuity. ### Safety Tips: - Make sure the vehicle's ignition is off before connecting or disconnecting the multimeter to avoid short circuits. - Be cautious when working with electrical connections to prevent any accidental shorts or damage. This method ensures that each pin is correctly providing the expected voltage, confirming the functionality of your 7-pin trailer connection.

I have to disagree. The aviation industry may have developed that solution for airplanes but that doesn't make it a best practice for all environments. The vibrations and shock to the wiring of a road going trailer are totally different. A passenger or cargo jet in constant service would subject its electronics and wiring to long term sustained vibrations at a frequency/amplitude that are determined by its propulsion and buffeting. Not nearly the same environment as a trailer that's pulled over a road surface. This is one of those rabbit hole discussions and imo both solutions would work fine in my application as long as they're done PROPERLY.

I'm an Engineer I WOULD HAVE SOLDERED THEM (and i did on my trailer) So long as you solder correctly - Clean solder tip - Use Flux - Heatshrink the connections - Waterproof the connections - Secure them in something like conduit or a junction box - Then waterproof the conduit and / or Junction box But comparing a trailer to an airplane is ridiculous, You can't compare a trailer to Avionics LOL You can use a termination block (FYI, it's TERMINATION BLOCK, Not Terminal Block), that's fine, but it depends on how much space you have as well. but as for solder joints... IT'LL BE FINE MATE, I've done this for years with my mates, and on my own trailer, going on 15 years now.. Still not a single problem. My mates who did it themselves with knife connectors, THEY FELL OFF OR BROKE OFF My joints are still going good again... IF YOU DO IT PROPERLY .... it works