No charging from TV

[Bruce and Jenna]

As far as I know, I have never seen 12v current in the trailer from the truck. Been thinking about it lately, as I am dry camping more here in the 49th state. I recently installed a 12v monitor to measure amps in and out. Which confirms no amps in when connected to the running truck. All running/stop/turn lights work fine.

I just tested my bargman outlet on the truck by plugging in an adapter that converts that 7 way outlet to a simple 12v power outlet (cig lighter). Gettin' power there. And believe I tested 12v power at the slowblow Shortstop fuse .


Which narrows the problem down to the trailer.

I looked at Workshop's Restoration 101 document. He shows the power going to 12v breakers. I don't know why he didn't provide detail on a 2007 33RSE.

I have not found any blown fuses in the front compartment. But then I don't see that wire on a fuse in that area. Truck has a 20amp fuse. The basement utility area is a rat's nest of wires. Hard to even get in there. But I assume that trailer wire connects somewhere in there or up to the converter.

Any ideas out there?

[rockintom]

Hey Bruce,

Just a couple of things to get started. You refer to amps when I think you mean volts. My Chevy Tug has a 40A fuse on stud 1 of the underhood Bus. 20 amp sounds a little light to power up a trailer connection. But that's not your question. I'd first check my terminals from your truck with a DVOM directly. That would be pin 4 (B+) and pin 1 (grd). You may have to have the truck running if your truck is equipped with an insolator relay. Then check the same pins on the trailer side with battery disconnect switch "on". Should have system voltage (B+) on both units at that point. Let's prove that and we can go from there. I think that workshop's basic schematic would be fall true on even our new rigs. Sounds like you are having fun in Alaska! Enjoy!

[Bruce and Jenna]

Thanks Rockin.

I do mean amps, as in 20amp fuse. Seems kinda light to me too, considering I have two alternators, one purchased specifically for more power to my trailer. But manual reads Trailer Tow battery charge - 20 amps. Plus a Full ISO relay - Trailer tow battery charge - don't know how that relates, (but I'll bet you do. Best I could find was A relay consists of an electro-magnet and a switch.)

I tried to test the charging pin on the truck trailer outlet using a 12v test probe. Couldn't get voltage there, tho I was able to detect voltage at the pins for the signals (blink, blink). And was able to get power from the smaller 4 wire outlet next to the bargman outlet.

So I plugged the aforementioned adapter into the bargman outlet. I was able to run my inverter on it, so figured I was getting power there.

Then I used my tester at the wire in the trailer at that Shortstop fuse, and could detect voltage only with the trailer plug connected to the truck while it was running.

Hence my assumption that the truck was putting out power.

You said Then check the same pins on the trailer side with battery disconnect switch "on". Are you referring to somewhere else?

[rockintom]

You said this: I recently installed a 12v monitor to measure amps in and out. I don't understand that....a 12V monitor doesn't measure amps. Basically, voltage is pressure and ampage is the amount of flow.

I mean check the pin 4 and pin 1 at the trailer harness (harness disconnected) with the batt. disconnect switch on. You should have B+ at that point....do you? Just trying to confirm basic info before moving forward. rockin'

[Bruce and Jenna]

12v monitor Trimetric on the trailer battery measures voltage, amps in and out, and % full charge based on parameters set in the meter. But here I am talking about monitoring amp into the battery, in this case no amps in with the trailer connected and the truck running.

Yeah, I tested pin 4 at the truck seven way outlet and saw no voltage. But did see it at the four pin connector. And at the Shortstop relay. And at the power adapter plugged into the truck seven way outlet. 18 months ago, a Ford dealer replaced that outlet with a new one and tested it. At 30 amps, according to the worksheet, btw.

[KU9L]

We had the older TriMetric TM-2020A in our off-grid PV system at our straw bale house. It is a powerful Voltmeter, Ammeter, Amp-hour meter, and battery % full meter for monitoring PV and wind battery systems. Properly installed, it would measure amps in solely from the TV "IF" the converter wasn't also connected to the grid or a generator and no other loads were sucking juice as well.

Dave

[Bruce and Jenna]

Originally Posted by KU9L

We had the older TriMetric TM-2020A in our off-grid PV system at our straw bale house. It is a powerful Voltmeter, Ammeter, Amp-hour meter, and battery % full meter for monitoring PV and wind battery systems. Properly installed, it would measure amps in solely from the TV "IF" the converter wasn't also connected to the grid or a generator and no other loads were sucking juice as well.

Dave

Thanks. I measured with the trailer buttoned up for towing, not connected to shore power. Solar controller and Trimetric read 2 amp. Plug in the truck - 2 amps. Conclusion - no power from the truck. I've tried this several times. Same results.

[rockintom]

Sorry, I didn't realize you had all this other stuff hooked up........this is way over my head, so I'll bow out. Sounds like you have some folks that are familiar with your system. Good luck. rockin'

[Bruce and Jenna]

Now hold on there, SKIA. I'm bringing you back in the game.

See, I called PI and talked with Tim. Who said that the black wire in the Bargman trailer wire harness to the truck is so small that it won't carry even an amp. Which would 'splain why I see no charge at my batteries.

According to Tim, the single heavier black wire on the left side of that Shorstop fuse goes to a 40 amp fuse at the battery. I think he said it's an 8 gauge wire.

But, and here's where you come in , that truck charging circuit has a 20amp fuse on it. So Ford must have designed it to carry close to that much current, yes? And I also detected 12v from the 4 wire plug next to it.

I'd like to measure the amperage here, but my digimeter tops out at 10amps, then starts smokin'. It's too young to smoke.

Could I run wires from the hot and ground on that four wire plug to the Shortstop fuse? The truck manual lists one fuse for the trailer charging circuit, plus the relay. Not separate fuses for each outlet. So I assume both outlets go back to the same source.

All this said, I do not want to risk burning up my truck. This ain't that important.

Whatcha think, oh wise engineer?

[Paul R. Haller]

You need to go back to basics and Check positively that you have power at the B+ and ground at the 7 way plug. If either is missing your trailer will not charge. Check and if necessary repair both B+ and ground at plug. I always upgrade this wire from the puny 14 or 16 gauge wire to a # 10 wire with a Relay between tow vehicle and receptacle with a 30 amp fuse near the alternator. Don't connect to the + side of the battery, go directly to the alternator output. That's about as much current the receptacle can deliver.You can just run a # 10 wire from the ground in the receptacle to a frame ground.also on the Tow vehicle. Now trace the wiring back or get a schematic from the manufacturer. They often use ingenious ways to wire everything including grounds making it nearly impossible to find B+ in the coach. Generally B+ from the drop cord goes to a breaker in the coach and from there to the batteries or power center. Ground in tv goes directly to trailer frame or the 12 volt neg side of power center or battery. Just because you get power in coach does not mean it's tow vehicle power. It could be trailer battery power. I would disconnect the trailer batteries B+ leads and with the tow vehicle plugged in and ignition on, start checking for B+ with the coach batteries disconnected so no confusion and the negative side of volt meter to neg side of coach battery. Check grounds too. It's the other half of the circuit. If necessary an additional ground and wire from drop cord to breaker can be installed if the original can not be found. Good luck and keep us posted.
-Paul R. Haller-

[Still Working "NOT"]

Bruce,

I don't know why you would have a 12 volt pin on the four wire plug. I have never seen one like that. Unless your tail lights are on when the truck is running.

Four wire plug is right turn, left turn, tail lights and ground.

If this is the case something is wired wrong.

You should have the 12 volt in the seven wire plug. And it only charges when the truck is running. At least that is the way my 1993 Ford is. You might make sure the the fuse is good with your meter. Is there two fuse boxes on your truck? If so check both diagrames for the the location of the fuse.

To check amps you can take a 12 volt light socket and place your amp meter from the 12+ to the red wire going to the light then ground the black wire from the light socket to the frame of the truck. This will not hurt your meter since you are only drawing the amps the light uses, which will be only .5 aqmps at most. Hope this helps.

SKIA gave the other info that you need. If not, I'll be online later tonight.

[rockintom]

I have a hard time believing Ford would have a B+ wire that wouldn't carry less than an amp of current. I'm almost sure (IIRC) the black #4 pin wire on my Chevy truck is #8....at the least a #10 wire. (I don't have an isolator relay) If I have low batts on the rig it takes about 4-5 hrs of run time to charge the trailer batts back up. The larger the wire the more current will flow (technically-up to a point). More good info from the previous posters. rockin '

[KU9L]

Last fall when we were exchanging our stuff from our old coach to our new one we didn't have a battery set for a couple of hours. I was to switch my 2 batteries from the old coach to the new one. I backed into the RV hookups at the dealer, but left my truck connected while we sat door to door exchanging our stuff. We didn't plug into the 30-amps with the new coach since the old coach was still plugged into it. As it was getting dark, DW turned on a light in the new coach and it baffled me how it was working since I hadn't moved the batteries yet. Then it dawned on me that I still had the 7-pin harness plugged into the truck, which was powering the coach lights even though the truck engine was off. It gave us the time needed to have lights in both coaches until I moved the batteries over and finally the 30-amp AC power. At least on our Chevy there is B+ on the 7 pin connector with the truck engine off, which I always remember when boondocking so we save enough to start the truck the next morning!

Dave

[rockintom]

Originally Posted by KU9L

Then it dawned on me that I still had the 7-pin harness plugged into the truck, which was powering the coach lights even though the truck engine was off. It gave us the time needed to have lights in both coaches until I moved the batteries over and finally the 30-amp AC power. At least on our Chevy there is B+ on the 7 pin connector with the truck engine off, which I always remember when boondocking so we save enough to start the truck the next morning!

Dave

Yeah Dave.......I hear ya on that. I've got a bit of a bad habit of leaving the truck hook up to the trailer when parking overnight and using our little 800W inverter. I'm an old country boy with an IQ of about 14....so I can't explain the scientific workings of why when you have a quick-start battery set up like in our truck connected (in parallel) with the deep cycle batts in the rig, the quick start batteries take the blunt of the load (even if the batts had similiar rating). IE they go down first. I've been lucky and when using the inverter it starts beeping at 11.6V to warn me, then will shut off completely at somewhere at 10.8V. I, of course, shut the inverter off at the warning and never have had a starting problem in the AM on ol' Tug. We usually have a several small items on the inverter (TV, Wireless router, computer battery charger, and cell phone charger. All this ends up being about 350 watts of continuous load. We can run usually about 4+ hours before getting the warning. We use 2-6V batts. (new). Just FYI rockin'

On edit: I have noticed the 2-6V batts do handle the load longer than our old group 27 12V batts we had in the old rig. I forget the ratings of the 2 different batts but the 6V win out for sure.