Hello!

I cut and pasted a reply post I put in my "Towing a Sailboat" thread because I'm hoping to get some help with a new problem that has arose.

"OK! New problem.....short story is after much frustration, Hubby checked the connector off the back of the van, a 6-pin, and found that the pin for the running lights had low volts and .1 amp. Suffice to say, that is not enough juice to run the lights on the boat trailer!!.... Now the lights (same lights) work fine for left and right turn signals, but no running lights......any suggestions?? Our temporary solution for the present is to get some battery operated lights, but if the problem can be fixed properly, quickly, and CHEAPLY....well then we'll do it, but we are leaving for our trip this coming Wednesday......Yikes!! Not alot of time, I know, but originally we thought the problem was faulty trailer wiring...that wasted some time, chasing our tails--so to speak.......

Oh yeah--correction on the boat size--its 17 feet, not 27 ft......seems like it's bigger to me!!

the Cowgirl Mechanic"

<!-- / message -->The Aero is a 1994 E4WD XLT with the factory installed tow package. I had a reply to check the fuses but cannot find the fuse box. I did read in a thread that there might even be a seperate fuse box panel that contains just the fuses related to the tow wiring. Anyone know where to find either of these fuse box panels??? Anyone have this problem before???

the Cowgirl Mechanic

 

This past March I bought a 1994 E4WD extended Eddie Bauer with the tow package on EBAY. I had to replace a broken side window on the driver’s side as part of the van’s rehabilitation. I removed the entire upholstery panel on that side to make the window replacement easier. There was definitely a fuse panel located under the windows between the rear wheel well and the rear air conditioning unit. I didn’t really pay any attention to it since it was marked lights and all mine worked. Maybe someone else remembers this fuse panel.

 

I think the fuse pannel box is located in the access panel for the rear A/C (between the second row and front row on the drivers side) It looks like a speaker vent.

 

Ok.....thanks to xrayjock and 93nighthawk, I found the towing package's fuse "box" panel!! Yea!! It was on the drivers side of Aero, next to where the 2nd/back seat bench was (do they call it the 3rd row seating??--just wondering..) Ffortunetly I had already taken that row out to haul some stuff this past week, so it wasn't in the way! Any-who....my van has some side "pockets" built into the paneling under the window, little caves with their own cargo net, and the one on the drivers side--the back "wall" was a panel that you could remove via two phillips head screws. Wa-LA!! Behind the panel was 4 nicely labeled fuses!! All for the tow wiring!!

Unfortunetly--all the fuses were intact......or so they seem to be....I'm thinking just to be on the safe side, to replace the fuse for the running lights....the fuses for the turn lights were 3 amp, the running light fuse is a 10 amp, and the backup light was....oh-heck...I don't remember right now, but I'm wondering if the 10 amp might be the wrong one or might have a hairline crack I cannot see......any thoughts guys????

the Cowgirl Mechanic

 

Don't use a DMM to check trailer wiring, use a test light. A DMM is actually too sensitive, you'll be reading transients and ground loops and it will mislead you.

 

What is a "DMM"??? Hubby used a test light AND an OHM meter. I did take the van to a local trailer shop. They used a specialized trailer test light. It plugged into the trailer plug at the back of the van and as you turned on different lights, it had a light labeled for each function that would light up if the plug was working correctly. The tester also had a "ground fault" light that would light up if the ground of the pin for the light you were turning on had a problem. It never lit, and the guy at the trailer shop says that the van is fine, the problem must be with the trailer!! Feels like I'm chasing my tail again!! HELP!!!

the Cowgirl Mechanic

 

DMM= digital multimeter. Includes a digital ohmmeter in most cases. It will mislead you unless you know what you are looking at . . . like that 0.1v reading.

Based on your trailer shop's test, perhaps you are missing a ground from the van to the *trailer*. Use a battery jumper cable from the van to the trailer to check that idea. You can also use your test equipment to do the same thing.

 

I'm wondering how you determined you had low voltage and a 0.1 amp draw with a test light and an ohm meter. Personally I'd rather have a DMM or analog meter than a test light.

Do you know what voltage you are getting at the trailer connector? Did you check it with the trailer connected or not?

It should be somewhere around 12Vdc. If it's less the problem is in the van not the trailer. Any problem with the trailer that would cause the voltage to drop that much would blow the fuse first.

A first guess is a bad connection between the trailer connector and the main wiring. It could be corroded or something. It's adding resistance to the path and the voltage is dropping across the connection.

If you can provide a little more info we might be able to narrow it down some more.

 

Ok, Hubby's OHM meter is one of those deluxe digital multimeter Volt/OHM/AMP/A/C D/C meters that can check/do about anything--it was quite expensive. That's how we got the low volts and 0.1 amp reading. I can have him test it again, but I'm sure he triple checked it, because he really wanted to make sure of the readings. (trailer connected or not I'm not sure--I'll have to ask him....he says he tested it both ways...with or without being connected it had 8 volts, and with boat connected, amps registered 0.1--not enough to power the trailer lights....he's an ex-physics major so he knows quite a bit about electricity.....its cars that he's not experienced with!)

The test light, well that's a bit long to explain. When the guy who installed the hitch last week wired it up, he checked it with a test light, and declared everything fine. Due to the possibility of me using this vehicle to pull a horse trailer, I had them install a 6-pin receptical (sp?). So I had to buy a "converter", an adaptor that would allow us to plug in his flat 4-pin for the boat trailer. The adaptor came with LED's that light up when everything is connected properly--an LED for each pin. When the adaptor is plugged into the van, all the LED's are lit brightly (no flickering/wavering lights). When we plug the boat into the adaptor, the LED for the running lights goes off completely.

So according to the test light the problem is with the trailer. But according to the OHM meter, the problem is not enough juice/power coming from the van!!

NOW!!! Tonight!! I hooked up my van to a friends trailer who's lights and wiring work fine. The turn signals work but the running lights wouldn't work. Unplugged my vehicle from trailer and plugged in their vehicle and all the trailer lights work just fine!! SO--CONCLUSION: Problem is with VAN not TRAILER!!!

But where is problem????????

asavage--you say it could be a ground issue (which I agree with...seems most likely...) but do I just touch a piece of metal on the van with a piece of wire to the trailer frame?? Or is it something I do related to the van's tow wiring to the trailer wiring ??? Or am I just chasing my tail again......*grrrr*...

the Cowgirl Mechanic

 

I agree it appears the problem is with the van not the trailer. I don't think it is a ground issue as it only appears on the running lights not all the lights.

Hook up the trailer and turn on the lights. Start with the connector and work your way back to the fuse block. Check the voltage at each junction. You should have 12 volts at the the fuse. If you only have 8 volts at the connector, you are dropping 4 volts somewhere. When you find where you loose the 4 volts you will find the bad connection.

 

CowGirl, Did your hubby check the relays in the trailer tow module? The one for the running lights may not be seated properly or may not functioning at all. You guys could probably find one at junk yard cheap. I know you checked the fuses and found them ok.

Xray

 

That's a DMM.

That's consistent with a bad ground. I've seen it before. I use a similar adapter for my own trailer.

We don't know how you or your husband are connecting the DMM, so I can't gauge that.

Yes. Use a jumper cable, like you'd use for jump-starting a car with a dead battery. Find shiny metal under the van. I use one of the mounting bolts for the hitch, they're not usually painted. Connect a battery cable end there (doesn't matter which color you use, but just to be consistent, use the Black cable end's clamp).

On the trailer, try to also find a shiny metal area and connect the other Black clamp to it. If your boat trailer has surge brakes (has its own master cylinder right at the tongue) then connect the cable further back toward the axle, because the surge brake mechanism isn't guaranteed to ground well through its articulation bushings.

When you've got your jumper cable connected to shiny metal on both rigs, re-try connecting the trailer connector and tell us what the LEDs do.

Just as a dbl-check, look at your adapter, the four-pin end. The male pin (metal part, often recessed into the plastic shell) is ground, if it's connected as it should be. The socket next to that is the taillight wire, the next socket is left and the last is right.

The reason why a real test light (I am talking about a 12v lamp with a cord and alligator clip on one end, and a sharp probe on the other) is preferable for this kind of work to a DMM is that the lamp is a real, 5W load and will tell you if you have a bad connection, where a digital voltmeter by itself will not -- not without a load (for the doubters: a DMM will show 12v right through a 100 ohm resistance, if there's no appreciable current draw). If you are testing between the ground pin on the adapter and one of the other pins with a test lamp, you can quickly see via a test light if each of the three circuits is powered at the pin/sockets -- I know the LEDs are right above those sockets/pin, but that's not a guarantee that the power gets to the pin/sockets: these things are assembled in China and are not NASA quality-assured!

So, do the independent ground thing first with the jumper cable. Still have no running lights? Leave the jumper cable on for now, disconnect the trailer connector from the adapter, turn on running lights (not headlights, no point in running down the battery) and hazard lights -- good practice to know how to find that hazard switch in a hurry, I'm always groping for it. Go back to the adapter, the three LEDs are all lit, the left one solid and the two others blinking. Use your 12v test light (if you have one, or your DMM if you don't) and probe between the ground pin (metal male pin) and each of the three sockets in turn. Are the results what you expect? Does your 12v test light or DMM show the same thing that the LEDs do? See how hard it is to use a digital voltmeter to check a cycling power supply? The display's update rate is too slow, unless you own a Fluke, and even then . . .

If the 12v test light works fine on that test, the van is wired suitably and since it will light your test 5W lamp, which is a good test load, it's time to tackle the trailer. I know, I KNOW, you've already tested the trailer, but I can't count how many times I've had mis-wired trailers, it's too common to discuss. I know it works with your friend's truck. It's possible that her truck is wired non-standard to match the trailer. No point in guessing: disconnect the jumper cable etc., turn the van around and open the hood. Get yourself some wire (and old extension cord will do, if you don't mind cutting it up) or better yet a couple of not-too-large nails. Clamp the nails into the ends of one end of the jumper cables. See where I'm going with this? No, you're not going to arc-weld

Connect the other ends of the jumper cables to the van's battery. Now you have a 12v power source at the end of two nails (probles, we'll call them). Don't touch them together! No fuse on this setup, the sparks will be good ones and we don't want to blow up the battery.

Get a friend to watch the trailer lights if you can, you don't want to do this last part while distracted. Push the nail on the black clamp into the end of the trailer connector's recessed female socket -- that's the one where the metal is socket is buried in the plastic off to one side, that's supposed to be the trailer's ground pin. Touch the other end to the exposed male pin next to it (running lights). Do the running lights come on? If not, there are only three things that could be wrong:

* No ground connection between the trailer connector and the trailer frame,

* Mis-wired,

* Bulbs out or bad light sockets

My money is still on the ground connection.

If no running lights at this point, continue holding the black clamp's nail to the recessed socket, and move the red clamp's nail to the middle pin. Left turn should light brightly. Move the red clamp's nail to the last pin (outside), and the right light should light.

One of those things isn't going to work. Possibly all of them will not work, in which case you want to remove the nail from the black clamp and clamp it to the trailer again (shiny metal) and repeat touching the red clamp's nail to the three pins, your helper watching for lights.

Report back.

Regards,
Al S.

 

Al,
Nice write up. Good point about the test light. I use meters (DMMs) often enough to be familiar with them. Still, I can see the advantage of the test light. Sepcially for lighting problems.

A couple of points though. If the problem is with the ground I don't see why it only shows up with the running lights.

Wired wrong? Both trailers and the other van would have to be wired wrong in the same way. Possible but not too likely.

The bad ground wouldn't explaint the voltage drop.

I may be wrong but I'm still guessing a bad or corroded connection.

Can't wait to see what it turns out to be.

 

Hey Guys, just thought you'd like the final chapter on this thread's story....I'm going to turn the keyboard over to the Hubby and let him explain how he solved the problem.....

Took apart the plug, found out the guy installing the hitch had used the wires for the brakes for the tailights. There was still no power at the tailight wire from the to module, though, so I ran the tailight wire from the van tailights instead. Now it works great.

 

Ok! Wass-Up with him! I told him to tell how he found the problem.....he weenied out on me! I went to bed before he wrote his reply.....I guess that's what I get for not being right there....

He didn't say how the problem solving went, so I will "fill in" the gaps....

Our friend was getting married in Tennessee and wanted us to bring her piano to her (it was here at her ex-in-laws house). So she rented a 5 X 8 u-haul trailer for us to use to bring her piano to her. Suffice to say, U-haul needs to know your wiring works before you take their stuff. So Hubby spent his day off on his back under the van troubleshooting the problem. He re-found the trailer fuses and checked and double checked the voltage, power, blah, blah, but since we didn't have a trailer here at the house, he couldn't check it out to see if it worked. In theroy, the plug seemed to work, but when plugged into a trailer, the running lights wouldn't work.

So, he decided to jumper over and bypass the module. He rewired it so the running lights would work (or so he thought...). Thinking the problem was solved, he called it quits and declared it fixed. I told him not to get to excited, as we had not hooked it up to a trailer. The next day I took it to the local U-Haul and hooked it up, just to see if the lights worked-- they didn't. Told Hubby, and he nearly blew a gasket. He said they have to work and said I must not have hooked it up right (as some may know, the U-Haul trailers wiring it kinda screwy--made to fit everyones situation). I told him I thought I had done it properly but maybe not.

I went to pick up the trailer, with fingers crossed, and the U-Haul guy hooked it all up, checked the lights and gave me the thumbs up. I thought "hummm, I must have done it wrong..." and went home. I left it all hooked up to the Aero, and when the Hubby got home, he wanted to check it out. Sure enough the lights didn't work. I was confused, Hubby was stumped. Did the U-Haul guy see the lights or was he blinded by the afternoon sun and only thought he did????

Now Hubby is bound and determined to solve this problem. He dives under the van again. A little while later he stomps into the house muttering about "incompitents", and says he figured out what the problem was and fixed it.

When the trailer hitch guy wired the plug he wired the brake wires to the running lights. The wire for the running lights was cut short, but just long enough to look like it was wired up into the plug, therefore giving the illusion that it was wired up properly. Only when he tugged on the wiring for the hundredth time, and had finally decided to take apart the plug and re-wire it himself (just in case there was an undectable bad connection or something) that he found the problem.

It's the old "***-u-me" issue again.....by the way, everything works great now, and the trip was fine.....and we got out of Tennessee just hours before all of the tornados hit!! Yikers, what a close call!

Any way that is the WHOLE story, and I hope ya'll got a smile out of it.


the Cowgirl Mechanic