Trailer wiring mystery!

[shibbershabber]

Just bought an 88 Shasta 210 trailer.
Its got a 7blade connector, elec brakes etc.

So, I have a 92 K1500 Suburban, with towing package.

I wired in a brake controller and a new 7blade connection. According to the instructions that came with both, its all correct.


When I hooked it to the trailer I had signals, flashers & brake lights. No tail lights or markers.

When i turned on the tail lights on my truck it would blow the 20A fuse.
After looking at the trailer connection, I found that the taillight and left signal wires were in the wrong space, as they correspond to my truck connector.

SO, I switched them so that they were in the correct position to match up to the truck...

Not blowing fuses anymore, but now I only have a right tail light, signals, 4ways, brakes.... NO left tail or markers

in addition to that I have found that the hotwire (part of towpackage) blows its 30A inline fuse AS SOON as I hook the trailer to the truck.

In testing voltage, I found that my hotwire reads +12 volts at the connector... the trailer's hotwire reads -12 volts...


Does that mean reverse polarity on the trailer? If that is the case, would that explain the blowing fuse everytime they connect?

The wiring that I can *see* looks okay... does this indicate that the trailer's hotiwre has grounded someplace?



Thanks!

 

[shelbyt.67]

U got a ground fault somewhere. First thing to check on those older trailers is the bulb housings. Haven't found one yet that wasn't corroded all to hell. Follow wiring all the way, and check all grounds. Guaranteed you'll find some frayed wire,corroded ground, or spaghetti bowl repair job.

 

[addiction2bass]

dito check wiring or just REDO all the wiring! if its a old trailer its just easier to rewire the whole thing than to try and track down wires and inspect them all. if its a 88 the wires are plenty old and with most trailers they sit around along time outside in the yard and all kinds of critters can really do damage all over from lights to even the power brakes.
my dads trailer we had to completly rewire from some mice crawling into the frame and chewing on wires so we just rewired everything. all the lights and the electric brakes at one time! 15years later still no problems with it other than my dad smashing the center taillight into a curb.lol

with old trailers ya never know how they have been wired by previous owners! if they THINK its wired one way they could have also had the wiring on there truck backwards where it will only work right on his truck.lol

 

[shibbershabber]

Turns out that the batteries had reversed polarity...

removed the batteries and everything worked.

So... now to sort out the batteries.

 

[shelbyt.67]

Cool. Deep cycle from academy or yer autoparts store.

 

[shibbershabber]

I called Interstate batteries to see if they will warranty them.... theyre less than 2yrs old.

Ill take them in this week and see

 

[addiction2bass]

If they won't warranty it then just drain the batteries over night. Just slap on like a fog light on it and once it doesn't work anymore throw the charger back on it he right way. I had to do that on my dads battery from him putting the charger on it backwards when it was drained. Ayear later still works good

 

[shibbershabber]

They wouldnt warranty them. I tried to drain them and then properly recharge as mentioned above... but the charger kept cycling on and off, getting hot and not charging the batteries.

I found some old deep cycles to throw in there and it stopped blowing the main fuse.

NOW, Im back to blowing the tail light fuse again. Going through the marker lights again this weekend

 

[addiction2bass]

what kinda charger you using? the charger i used was a pretty large charger that is on a timer not a auto cycling charger.