Just a bit more info to make your head spin . If you have a compass handy. Test each magnet individually with your battery. If it is working correctly the compass needle will swing towards the magnet. You will then know without a doubt that your magnets are working.
BTW, On the standard 7 way connector, the current standard is center pin = back up lights. Makes sense that you have no current there.
I checked the 11 o'clock position on the umbilical while disconnected from TV and connected to trailer. This position tests hot with a test lamp. However, the diagram in the service manuasl show this position is the ground line and identifies the center position and the charge line. The center position does not test hot. Are these results as they should be? The 7 o'clock postion is the correct postion for the brake controller line.
This is exactly why I earlier assumed the ground and charge line had reversed wiring. To me the implication was the ground line (11 o'clock) should be negative and the charge line position (center) should be positive. Now it appears that my wiring tests out as Howie described and this polarity is normal. Vat is das?
OK I had missed the fact that you have a 71 trailer. The info I have been giving is for the newer Bergman 7 pin plug. However it appears your umbilical is wired for the newer plug that is most likely on your truck. Given that and given that the 11 and 7 oclock postions do test as expected you should be able to connect one brake and do the wheel spin test.
Yes if you do not have a jack connect one brake and while holding a compass at the 6 oclock position to the brake drum, in under the trailer or outside against the wheel you should see the compass move when the brakes are applied. Just make sure the compass is not oriented north and looking at the brake drum before you apply the brakes. Any needle defelction when the brakes are applied will indicate the magnet is connect.
Your new axle may require brakes shoe adjustment once you have confirmed that the magnets are connected.
A different question but why did you only replace one axle? Airstreams do not equalize between axles and you may have significantly changed your tongue weight as one axle may be carring more load than the other.
it appears your umbilical is wired for the newer plug that is most likely on your truck.
The truck is a 99 I'm not sure if the plug is stock but it is definitely newer than 71
Quote:
Originally Posted by HowieE
Yes if you do not have a jack connect one brake and while holding a compass at the 6 oclock position to the brake drum, in under the trailer or outside against the wheel you should see the compass move when the brakes are applied. Just make sure the compass is not oriented north and looking at the brake drum before you apply the brakes. Any needle defelction when the brakes are applied will indicate the magnet is connect.
So I check the magnets work by putting a compass next to them and check the compass works by putting them next to the magnets
Quote:
Originally Posted by HowieE
A different question but why did you only replace one axle?
Cuz for right now the other axle is holding the trailer up
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Like a couple of Balboas we headed into the wild pavement of yonder with a monstous piece of aluminum hooked to our rear end. "The Long, Long Trailer".
One pin on your 7 pin connector should be bigger than the others, that one is the ground. If you put that at 12:00, the the brake actuator is at 4:00. Power is in the center.
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"Not all who are lost are wondering" say Bill & Heidi
'78 Excella 500,"The Silver Pullit". vacuum over hydraulic disc brakes, center bath, rear twin. '67 Travelall 1200 B 4X4 WBCCI 3737
I've zeroed in on the problem. I can say I am almost absolutely sure it's a crossover between the left top light/ turn signal line and the brake ground wire. Here's how I figure it. I disconnected all 8 leads to all 4 brakes and both black and white lead wires are hot when the brakes are applied in the TV, so it is not a magnet short to ground. If I only connect the brake controller line in the umbilical only the black leads to the brakes are hot. When I connect the left tail light umbilical line the white leads to the brakes are hot. So there MUST be a short between the left tailight wire and the brake ground wire, I think. Most almost certainly where the wiring hooks up to the 7 way in the front of the trailer. Time for a beer, or two.
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Like a couple of Balboas we headed into the wild pavement of yonder with a monstous piece of aluminum hooked to our rear end. "The Long, Long Trailer".
Well my wiring is OK from the TV to the 7 way connector and there is no problem with the brakes themselves, but the ground wire still tests as hot. So the problem must be located between the 7 way and the brakes. For some reason yet to be determined the ground wire becomes charged when the left turn stop wire is charged, which cancels out the brakes. Short of tearing the trailer apart I can't thhink of a way to find the exact problem.
I still have some unanswered quesitions about the connections around the 7 way:
1. There are 2 red wires attached at the 7 way connector left turn stop light position. Could one go to the little turn signal indicator on the side of the trailer that you can see in the side view mirror?
2. The manual shows heavy white ground wires grounded to the shell with the bolt that attaches the 7 way to the skin. They are not. Maybe a PO dissattached them because of the left taillight/ brake ground short, or maybe somehow it is part of the cause of it?
Anyway thses problems have been around for a while (and there is a good chance I have been towing without brakes for a while) and the coach has not burned to the ground so I am going to leave things until I am feeling more anal about tracking the problem down. I would rather go camping.
I now have brakes that work. Albeit a chewing gum solution for now. Since I have no problem with the + black line to the brakes and the only problem is with the ground, after hooking up the + line I ran a short line from the 2nd brake lead grounded to the belly pan. Also a back up ground line across the axle so each brake is grounded individually to the belly pan and shares the ground with the other brake on the axle. I fugure since each brakes only draws 2 1/2 - 3 amps this is a safe workaround.
Incidentally while crawling around under the belly of the beast like a worm from hell I found some belly pan rivets that had pulled through and one bolt on one of my stabilizer jacks had broken off. I fixed the rivets with 3/16" wide head blind rivets and may tackle the stabilizer jack today if I feel ambitious.
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Like a couple of Balboas we headed into the wild pavement of yonder with a monstous piece of aluminum hooked to our rear end. "The Long, Long Trailer".
I have no idea what the extra wire could be. The indicator on the side of the trailer uses fiber optics and no electricity. There is no telling what a PO may have done in the past.
I checked the 11 o'clock position on the umbilical while disconnected from TV and connected to trailer. This position tests hot with a test lamp. However, the diagram in the service manuasl show this position is the ground line and identifies the center position and the charge line. The center position does not test hot. Are these results as they should be? The 7 o'clock postion is the correct postion for the brake controller line.
This is exactly why I earlier assumed the ground and charge line had reversed wiring. To me the implication was the ground line (11 o'clock) should be negative and the charge line position (center) should be positive. Now it appears that my wiring tests out as Howie described and this polarity is normal. Vat is das?
The input connector on the front of your trailer does not have the same pin configuration as the new RV standard plug with the flat 7-pins.
You are looking at Airstream's way to configure the pins. Modern 7-way flat connectors are wired in a different configuration.
The iinput connector on the front of your trailer does nothave the same pin configuration as the new RV standard plug with teh flat 7-pins.
You are looking at Airstream's way to configure the pins. Modern 7-way flat connectors are wired in a different configuration.
Early in this thread I said it appeared the ground and charge line had been reversed. It appeared this way because of the wiring configuration difference Uwe describes above. Either changing the wiring confiuration in the trailer side of the umbilical or at the 7 way will make the accomodation, but will be out of sync with the schematics and may lead to confusion (did with me) for someone working on the system if they are not aware of this issue.
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Like a couple of Balboas we headed into the wild pavement of yonder with a monstous piece of aluminum hooked to our rear end. "The Long, Long Trailer".
Early in this thread I said it appeared the ground and charge line had been reversed. It appeared this way because of the wiring configuration difference Uwe describes above. Either changing the wiring confiuration in the trailer side of the umbilical or at the 7 way will make the accomodation, but will be out of sync with the schematics and may lead to confusion (did with me) for someone working on the system if they are not aware of this issue.
Just keep the truck side of the umbilical cord to the new RV standard, and make a note of which wire does what, by color. Button it up...
Now, take Airstream's version of thow hings shoulda been wired in 1971, and put the wires in place according to their plan. This is not difficult, and will work just fine. Your trailer is already wired from the input connector on back, so it's just a quick adaptation.
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. If you have a compass handy. Test each magnet individually with your battery. If it is working correctly the compass needle will swing towards the magnet. You will then know without a doubt that your magnets are working. 
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