BT7800

Hi, Very first post here and hopefully this forum is as helpful as forums like the one for my Chevy Astro van, don't know what I'd have done without their help! (well would've just had to get a third job to pay for the fixes they helped me fix myself!!!)

I've got a new business going and need to often pull an enclosed 10 foot trailer that I've had for a while and which I installed electric drum brakes on, after pulling a load that wasn't ridiculously heavy (trailer weighs 1,020lbs and max load is 1,480 lbs for a nice round total of 2,500 lbs but I've exceeded it a little at times and without any issues at all, this load of landscape blocks would've been just under 2,800 lbs-which is as about as far as I'd push it) I was pulling it with my Astro van, on a perfectly dry day and when hitting the brakes on as asphalt road going 30 mph max, the ABS started up, so without ABS I would've had wheels locking up as I tried to stop and it wasn't like I was attempting a panic stop at 70, or else I'd probably not be here today! So, got brakes, controller, etc for Astro and things were great since then.

Now, my brother sold me his 2000 Tahoe LT for a super low price, owned it since new and its been VERY well cared for, just need to get my new controller installed as I'm leaving the old one (a Prodigy) in the Astro since I still use it as well. Money's tight for a while, so I bought a timer type controller (I know proportional is far better, just need to watch the $$ for now!) and was THRILLED to find out about the harness that plugs into the fuse block type box under driver's side of dash (Astro was 10x harder to wire, lots of people tow with them, no clue why not a box like Tahoe has) but THOUGHT I had everything wired up just right and I'm having some problems I just can't ignore due to the obvious safety factor!

My bro never trailered anything with it, but it came with a 7 pin harness all hooked up and even in the standard rear bumper mount they seem to use for any truck w/7 pin harness, but it looked very old and beat, here in SE WI our winters can be tough and use (lots) of salt on roads, so after 15 years and 240k+ miles, I'm not surprised and went to a local RV/trailer parts shop and bought a new, GOOD QUALITY 7 pin harness and the type where I can splice the wires to those on the truck, NOT the type where you make the connections right on the back of the truck side plug, which I HATE!

I should make clear that I've got a LOT, TONS of experience with both auto and low voltage elec connections, whether its soldering and shrink tubing them or using butt/barrel connectors, ring connectors to a terminal block-whatever and I'm 100% sure my connections are ALL solid.

Here is my issue:
-The brake controller box DOES seem to have power, it lights up when I push one of the buttons, seems like it should work fine, yet there is NO POWER when I hook my multimeter or my test light to test it, using either the ground spade on the truck side harness connector OR grounding it to the truck frame. Everything I've read, which usually centers around the underhood big fuse block and if there's a maxi fuse in the spot all the way to the left of that top row of maybe 8 spots for all maxi fuses. I've got one in, I forget but its the proper size, either 30 or 40 amps and still fine. Yet, I've also read that fuse is simply to fuse to 12V power going to the trailer on a separate connector spade, so I don't even know if that has anything to do w/powering the interior brake controller box.

-I also originally had ground issues on the truck side, the ground seemed very weak at best, but that was easily solved by drilling tiny hole in frame, using power drill to buzz off the bit of surface rust for a great connection and now I've got a GREAT ground, no issues there anymore.

So, long post I guess for a simple question, but other than whatever wire being cut somewhere and somehow that runs from the box under the driver's side dash back to where I can first see the harness wiring appear at the back of the truck, I'm clueless! I doubt that though, unless it has some weak spot someplace, as my brother is NOT a guy who does any mods or even his own maintenance on his cars, so its not like he would've accidentally cut it and forgot about it while installing like a sub box with 4 15's and some huge amp, extra fog lights, or whatever else! He's not at all the type to dare to wrench on anything auto wise (unlike me!)

ANY advice or ideas are VERY appreciated, just got new biz going and must be darn careful on spending $$$ till things are off the ground, so hopefully someone has a great idea, thanks!!!!!!!!

intheburbs

If the controller is operating properly and getting power, something on the display should light up when you tap the brake pedal. Other than that, I'm not sure you'll be able to do anything unless a trailer is hooked up. I know my Tekonsha Prodigy lies "dormant," except for one little dot LED until I hook up a trailer. That was in my '01 Suburban, which should be pretty much identical to your '00 Tahoe.

Having said that, have you tried it by actually hooking up your trailer?

Lastly, be really careful about waterproofing/corrosion-proofing your connections out back. Stuff will corrode back there VERY fast. Use plenty of conductive grease and shrink tubing.