Gary,
I didn't reply to your question cause hazmat answered better than I could have.
Hazmat,
I can't thank you enough for the advice and explanations.
Lucy, it's been interesting.
I spent most of Monday either on the phone or on the road trying to find out how the factory wired the truck for the brake controller. I found out I was in uncharted territory. The GM tech line if for techs only. Most service advisors aren't interested in doing anything besides lip service. Makes you almost wonder if they've missed their calling or if we've really missnamed the job they do.
Tuesday was figure it out day. The trailer brake wire at the rear plug is cut off in the wiring loom under the hood just below the A/C--heater assembly. It ends there, goes nowhere. Of course to find this little piece of information one has to remove the plastic fender liners. And then cut the tape around the loom and open the plastic split hose the wires are in. Then one has to ask a bud to old the test light on the blue wire going nowhere while one goes to the plug and runs a jumber from the constant hot lead to the trailer brake lug. The light came on, one thing found out for sure.
The whole object of this excerise was to avoid jerry rigging the wiring. I was positive that since the factory had done such a beautiful job on all the other wiring they had done something really trick for the brake controller. I just had to find out what where.
In the big fuse box is this thirty amp ciruit breaker. It reads "electric trailer brakes". The wiring loom that leaves the fuse box has eight twelve and ten gauge red wires amongst all the other wires going to whatever. You can see a twelve gauge red wire going into the trailer brake circuit breaker.
The loom goes through the firewall without a red wire leaving as many other wires in looms do here and there going to whatever.
So it's simple. Pull the breaker and take apart the dash. Check each and every twelve gauge red wire for current. If one is dead plug back in the breaker and see if it comes hot.
No dead reds to be found.
Find out where the loom comes through the firewall. Remove the tape and using a probe very very carefully test each red twelve gauge for current.
No dead reds to be found.
Go to the hood side of the firewall. Count the twelve gauge reds, three, first one probed is dead. Plug back in breaker, it becomes hot. Do this three times to make good and sure it's the right one and only one. Verify the wire is going through the firewall in the loom. Hunt for it again on the inside. It's not there.
Finally after repeated attempts to understand what the heck is going on in only two inches of space decide it must be cut and taped back as it goes through the firewall.
Go buy four greasefilled connectors for attaching twelve gauge wires to go from under the hood to the brake controller by the driver. If you don't use grease filled connectors you're gonna have trouble down the road. Trouble only comes at the worst possible moment. Just the way it is.
Waste two of the connectors because of the working space, or lack thereof, figured that might happen, why I bought four. The rest of the hooking up of controller works like it should. I am satisfied with the installation. But it was a bugger bear putting everything back so that you can hardly tell I dug through all those looms.
Today was installing toolbox and aligning bed day. It went well. I'm just slow. I keep thinking that I'm not gonna do this again for many years. If I do it wrong or miss something I'm gonna cuss myself for years and years. I dislike being cussed so much that I work real hard to avoid it, even by me.
BTW I'm having fun.
I am still having trouble getting use to the new design of the Chevy's heavy duty truck. I am sure it will grow on me like all other designs(except the Aztez, man that thing was ugly). Have fun.
