I have an 93 gmc sierra with the flat 4 wire harness on it and i just bought a boat and the trailer has the electric brakes (shorlandr). How do i wire the harness so that the brakes will not engage when going in reverse? Someone mentioned that a wire gets hooked up to my reverse lights or something of that nature. Any tips would be greatly appreciated

The trailer probably has a "flat-5" pin connector, which has a 5th (typically blue) pin. On the vehicle side, this gets wired to the back-up light circuit, so it provides 12volts when the tow vehicle is in reverse. This signal actuates a solenoid on the brake actuator, preventing the disc brakes from actuating when you back up. So, you can convert your truck to a flat-5, or make an adaptor, with a pigtail that gets wired to your back-up lights.
If you're unsure on how to do this, any competent trailer shop should be able to easily take care of it for you.
Here's the Shorelandr owners guide, wiring starts on page 6.
HRG
http://www.midwestindustries.com/documents/manuals/2010%20OWNERS%20GUIDE.pdf
here's an adaptor: http://www.amazon.com/Hopkins-Plug-Simple-47515-Adapter/dp/B000CMHVGM/ref=sr_1_1?ie=UTF8&s=automotive&qid=1264098258&sr=8-1

Thanks HRG that helps me out alot more then i was thinkin... so i went to fleet to pick up the plug that i would need now its just finding the wire that activates the reverse lights lol. Seems like an easy wiring deal as long as i can get at the wires underneath..

. so i went to fleet to pick up the plug that i would need now its just finding the wire that activates the reverse lights lol
I think it's light green.

Okay... Shorelandr says to unplug the trailer wire harness before you back your trailer into the water at the ramp..... how does the disc brake actuator work to disengage the brakes when backing up IF the harness is not plugged into tow vehicle?

You will be backing down a slope at the landing and the trailer will not be pushing on the truck, thus the surge brakes should not be activated.

All above is correct. There should also be a manual lockout feature on the trailer.

BTW... Your trailer has SURGE brakes not ELECTRIC brakes. :cheers:

-Eli

well a small update here i ended up getting a new truck as to my 93 ended up blowing up when pulling a trailer with my atv on it.. i ended up with a 07 gmc sierra 1500. question i have is it has the round plug on the truck 7 prong i think. so if i could find an adapter that would go from 7 round to 5 flat would the surge brakes work like they
should or would i still have tap into the reverse lights with that wire?

check your truck with a voltmeter, but the large center pin could be wired to the back-up light circuit, and it looks like the 7 to 5-flat adapter are wired with the 5th pin to the center tap, so you should be good to go. But, check the truck first.
here's an adapter:
http://shop.easternmarine.com/index.cfm?fuseaction=catalog.prodInfo&productID=5400&categoryID=284,
if you click on the instructions, it will show what I'm talking about.
HRG
here's the Hoppy version: http://www.hopkinstowingsolutions.com/doc/47375.pdf

thanks hrg thats what i was looking for thanks for your help i will check the truck out later to day when it warms up lol