Am I missing a wire?

[pappysnap]

Any help and/or advice greatly appreciated. I’m working on a 1969 Airstream Caravel. I just need the marker lights, brake lights, and left and right turn signals to work using a 4-pin flat connecter. On the left side there is a red wire which I have matched up to the left turn Signal. Also on the left there are two green wires which I have matched to the marker lights. Also on the left is a black wire which I have matched to the backup light. Since I am only concerned with a 4-pin flat connecter I’m assuming I will not use this wire. On the right side I have two black wires which are matched to the backup light so, again, I will not use them. Also on the right are two green wires which I have matched to the marker lights. There is a brown wire on the right which I have matched to the right turn signal. Also on the right side is a red wire that is a loop. It is the same red wire that’s on the left side. In other words, if I pull the red wire on the left it pulls the loop out of the red wire on the right. On the front of the trailer there is a 10 gauge white wire which I have grounded to the frame and then continued to connect to the white wire coming from the tow vehicle. When I connect a bulb (1157?) to the turn signal wires on either side they work, although it seems not too bright. When I apply brakes the brake side of the bulb does not light. The bulbs have a red lead and a white lead. I’ve tried connecting one lead to the marker lights using a pigtail and the other lead to the turn/stop wire but that doesn’t work and I reversed them and that doesn’t work. It seems like I must be missing a wire on each side. I’ve watched a lot of video and read blogs but this is my third day and I just can’t figure it out. Thanks for any suggestions that will help me troubleshoot. Are my photos showing up?

[Wazbro]

On a 4-pin flat connector, the 4 wires are 1-ground, 2-running and marker lights, 3-right turn and right brake lights, and 4-left turn and left brake lights, not necessarily in that order.

What are you doing about brakes?

[Jcondon]

On my 69’s the original wiring was as follows: green = running lights, brown = right turn and stop, red= left turn and stop, and white is ground. So on your 4 pin wiring yellow will connect to red, green will connect to brown, and brown will connect to the green. And white connects to white and the shell. Crazy huh?

[richard5933]

Depending on your tow vehicle's wiring, you might need a wiring adapter between the TV and the 4-pin plug. I believe this is when the TV uses separate wiring for the brake lights and the turn signals. Otherwise things get kind of wonky since the trailer uses the same wire to power the turn signal as the brake light on each side.

[pappysnap]

Originally Posted by Wazbro

On a 4-pin flat connector, the 4 wires are 1-ground, 2-running and marker lights, 3-right turn and right brake lights, and 4-left turn and left brake lights, not necessarily in that order.

What are you doing about brakes?

I really appreciate the question.

I originally started with a 7 pin. On the TV side the blue wire tested as the trailer brake. After accounting for turn/stop/marker lights left and right I tried the blue wire first with a red (10 or 12 gauge) wire and then with the yellow wire. Neither one of them connected with the brake controller on the TV. On the back side of each tire there are two wire nuts and they are well connected. That’s as far as I went. The brake controller shows “not connected” so I don’t think it’s a fuse. Right now I’m just trying to get a 4 pin to work the turn/stop/marker lights. Today I plan on rechecking continuity front to back for the turn/stop/marker lights.

[pappysnap]

Originally Posted by Jcondon

On my 69’s the original wiring was as follows: green = running lights, brown = right turn and stop, red= left turn and stop, and white is ground. So on your 4 pin wiring yellow will connect to red, green will connect to brown, and brown will connect to the green. And white connects to white and the shell. Crazy huh?

Yes, it’s crazy! Thank you. So I connected the 4 pin to the TV and used my test light to determine which pin did what function. Then I matched those results to the camper. Now I will go out and check the colors. Thank you very much.

[pappysnap]

Originally Posted by richard5933

Depending on your tow vehicle's wiring, you might need a wiring adapter between the TV and the 4-pin plug. I believe this is when the TV uses separate wiring for the brake lights and the turn signals. Otherwise things get kind of wonky since the trailer uses the same wire to power the turn signal as the brake light on each side.

This might be my Eureka tip! The TV is a 2004 Ford F-150 Lariat with a trailer tow package. This would seem to account for only one side of the 1157 lighting up. I’ll Google this and see what I can find. Do you have any more info about this adaptor? I was completely out of trouble shooting ideas. My hope is restored! Thank you!

[richard5933]

Originally Posted by pappysnap

This might be my Eureka tip! The TV is a 2004 Ford F-150 Lariat with a trailer tow package. This would seem to account for only one side of the 1157 lighting up. I’ll Google this and see what I can find. Do you have any more info about this adaptor? I was completely out of trouble shooting ideas. My hope is restored! Thank you!

Check with a place like eTrailer and see if they have an adapter specifically made for your vehicle. Makes the whole thing tons easier.

[pappysnap]

Originally Posted by richard5933

Check with a place like eTrailer and see if they have an adapter specifically made for your vehicle. Makes the whole thing tons easier.

I called eTrailer and they did not have a solution. They suggested connecting the TV to another trailer to see if the the same problem occurs. I towed my son-in-law’s trailer several weeks ago and didn’t have a problem. Please let me know if you think I’m missing something. Thanks.

[richard5933]

Originally Posted by pappysnap

I called eTrailer and they did not have a solution. They suggested connecting the TV to another trailer to see if the the same problem occurs. I towed my son-in-law’s trailer several weeks ago and didn’t have a problem. Please let me know if you think I’m missing something. Thanks.

You towed it with the 4-pin or the 7-pin?


I just reread the thread and am confused why you're not working with the 7-wire system since you will need at least 6 of those conductors before you're done: left/brake, right/brake, running lights, brakes, positive, negative.


Regarding the brakes, if you are talking about seeing two wire nuts behind each trailer tire, one is likely the positive feed originating in the 7-wire harness, and the other is likely the ground wire. All the positives will be connected in parallel. If you don't have a solid ground connection to the tow vehicle I'm not sure your tow vehicle will recognize the completed circuit for the brakes.

[Jcondon]

Originally Posted by pappysnap

This might be my Eureka tip! The TV is a 2004 Ford F-150 Lariat with a trailer tow package. This would seem to account for only one side of the 1157 lighting up. I’ll Google this and see what I can find. Do you have any more info about this adaptor? I was completely out of trouble shooting ideas. My hope is restored! Thank you!

Your 2004 F150 with tow package should have a four pin flat trailer connection prewired for your plugging in pleasure. You should not need an adaptor of any kind unless your truck is no fitted with the flat? Anyway the lamp holder with the 1157 dual filament bulb has one wire for the left or right turn and stop light and the other is a running light. So when the turn signal is off the running light stays lit if the running lights are turned on.

[pappysnap]

Originally Posted by richard5933

You towed it with the 4-pin or the 7-pin?


I just reread the thread and am confused why you're not working with the 7-wire system since you will need at least 6 of those conductors before you're done: left/brake, right/brake, running lights, brakes, positive, negative.


Regarding the brakes, if you are talking about seeing two wire nuts behind each trailer tire, one is likely the positive feed originating in the 7-wire harness, and the other is likely the ground wire. All the positives will be connected in parallel. If you don't have a solid ground connection to the tow vehicle I'm not sure your tow vehicle will recognize the completed circuit for the brakes.

I initially tried to use the 7-pin. Continuity was confirmed front to back for left turn/stop, right turn/stop and, marker lights. The 69 Caravel has backup lights so the 4th wire was for backup and the continuity was good. The 5th wire is the white ground coming from the TV then connected to the white wire on the camper and then grounded to the skin then continues to the rear compartment and attaches to a ground bus in a distribution panel then continues to the negative side of the battery. The 6th black wire on the TV side connected to the black (10 gauge) on the camper side for battery charging. Like the white common it continues to the distribution panel and then is connected to the positive side of the battery. I actually have 8 wires on the camper side. The two wires remaining are yellow and red and both are larger than 14 gauge. The one remaining wire on the TV is blue, 10 or 12 gauge. It lights up the tester when I apply the brakes. I connected it to the yellow on the camper side but brake controller showed not connected. Same thing with the last red wire on the camper. I changed to the 4-pin harness thinking it might solve the turn/stop/marker problem but I have the same problem so your right. If I can solve the issue I will use the 7-pin cord. On the rear left tail light I have one red wire which I traced out to be the left turn/stop. I have a black which is backup. I have a green which are marker lights. Same thing on the right except the turn/stop wire is brown. I’m using VTS lights which have two filaments and two leads, one red and one white. VTS says that both these leads are positive and the bracket serves as the ground. I’m assuming that one of the leads is for turn signal and the other is for stop. On the left side I only have one wire for both turn and stop. Since both signals are in the one wire I pigtailed it and used one side on the white lead and the other on the red lead but it didn’t work. Hmmmmmm! I just realized that I was using just the bulb with its two leads and not the fixture which means it wasn’t grounded. Let me try that again. I really appreciate your ear and advice.

[richard5933]

Can you physically trace the wires coming off the trailer brakes. On side should connect to the ground/negative, and the other should continue to the 7-pin cable. That wire is the one you need in order for the controller in the truck to recognize the brakes, as well as a good ground.

[pappysnap]

Originally Posted by Jcondon

Your 2004 F150 with tow package should have a four pin flat trailer connection prewired for your plugging in pleasure. You should not need an adaptor of any kind unless your truck is no fitted with the flat? Anyway the lamp holder with the 1157 dual filament bulb has one wire for the left or right turn and stop light and the other is a running light. So when the turn signal is off the running light stays lit if the running lights are turned on.

Yes, I have the 4-pin flat connector along side the 7-pin round. I think the adaptor was suggested on the off hand chance that the turn/stop functions on the TV were split, one wire for each but that’s not the case. You answered my next question before I had a chance to ask it and that is how to get the marker lights involved. I think my issue is is failing to ground the fixture. I was testing with just the bulb and two leads. It needs the fixture so that it’s grounded. I now have some hope that my issue is solved. Thanks for your help and I’ll be back again with an update.

[Jcondon]

Originally Posted by pappysnap

Yes, I have the 4-pin flat connector along side the 7-pin round. I think the adaptor was suggested on the off hand chance that the turn/stop functions on the TV were split, one wire for each but that’s not the case. You answered my next question before I had a chance to ask it and that is how to get the marker lights involved. I think my issue is is failing to ground the fixture. I was testing with just the bulb and two leads. It needs the fixture so that it’s grounded. I now have some hope that my issue is solved. Thanks for your help and I’ll be back again with an update.

You should concentrate your efforts on the seven pin connection. I have yet to see a 69 with good brake wires. Go to your break away switch in front. Using your meter measure the resistance of the blue wire to ground. If you read around 1 ohm apply 12 volts to it and measure the current. You should read 8 amps per axle. 16 amps for dual. It’s hard to distinguish between a dead short and a brake magnet with a meter because the resistance is low in both cases.

[pappysnap]

Originally Posted by richard5933

Can you physically trace the wires coming off the trailer brakes. On side should connect to the ground/negative, and the other should continue to the 7-pin cable. That wire is the one you need in order for the controller in the truck to recognize the brakes, as well as a good ground.

I have 8 wires, 4 behind each wheel. Is the ground/negative only on one side?

[richard5933]

Originally Posted by pappysnap

I have 8 wires, 4 behind each wheel. Is the ground/negative only on one side?

Should be two wires coming out of the back of each brake backing plate.

All the grounds might join together and connect to the chassis together. Or they may not.

[pappysnap]

Originally Posted by pappysnap

I have 8 wires, 4 behind each wheel. Is the ground/negative only on one side?

I am so sorry. I have 4 wires, 2 on each side. On each side two of the wires go to the brakes and the other two go up into the belly pan. I can’t trace those.

[pappysnap]

Originally Posted by Jcondon

You should concentrate your efforts on the seven pin connection. I have yet to see a 69 with good brake wires. Go to your break away switch in front. Using your meter measure the resistance of the blue wire to ground. If you read around 1 ohm apply 12 volts to it and measure the current. You should read 8 amps per axle. 16 amps for dual. It’s hard to distinguish between a dead short and a brake magnet with a meter because the resistance is low in both cases.

Thank you and yes I have decided to stick with the 7-pin. Your advice is great but my skill level is lacking. I have an amp meter I use to check continuity but I’m assuming your talking about an ohm meter which I’ve never used. The breakaway switch has two wires connected to two wires that appear to be inside the tongue. One is red and the other is yellow. When you say blue wire are you referring to the blue wire on the new seven wire cord?

[pappysnap]

Originally Posted by pappysnap

Yes, I have the 4-pin flat connector along side the 7-pin round. I think the adaptor was suggested on the off hand chance that the turn/stop functions on the TV were split, one wire for each but that’s not the case. You answered my next question before I had a chance to ask it and that is how to get the marker lights involved. I think my issue is is failing to ground the fixture. I was testing with just the bulb and two leads. It needs the fixture so that it’s grounded. I now have some hope that my issue is solved. Thanks for your help and I’ll be back again with an update.

My issue is not resolved. When I turn the left blinker on the TV the left turn/stop wire blinks. But it only operates one side of the bulb when you hook up the fixture and apply the brakes. I’ve owned quite a number of vintage trailers but I’ve never had this much trouble before.

Am I connecting the wires correctly? On the left side rear I have a red wire that is the left turn/stop. I connected it to the red lead on the tail light fixture. I have a green wire that is the marker lights. I connected it to the white lead on the fixture. When I turn on the lights, blinker, and brake on the TV only one side of the bulb blinks. I reversed the connection on the light fixture and got the same result.