Towing question

woodm · March 13, 2014

...intheburbs, I am only describing what was necessary to complete this task on my truck. Without steps 2 and 3, I would not have power to the 7-pin connector for the trailer brakes, therefore, these steps were essential in my case. Apparently GM offered a standard trailer wiring option and a heavy duty trailer wiring option for the 2000 model year. Clearly, my truck is equipped with the standard trailer wiring option and therefore requires these extra steps in order to enable trailer braking.

bruce69camaro indicates he has the same model of truck, therefore, he may need to follow the same procedure.

intheburbs · March 13, 2014

Ok, you're right. My apologies.

Bruce - look for code Z82 on your glove box RPO code label. If you have Z82, it'll be the simple procedure that I described. If not, you'll have to do what woodm suggests.

bruce69camaro · March 13, 2014

Woodm,

Thank you for that great summary, that is exactly what I was looking for, because even though like others have stated, it "SHOULD" be an easy plug and go type deal "BUT" if mine wasn't already wired up, what then would I need to do?

It looks like one of the hardest issues is trying to find the hidden wires. Were the wires from the plug easy to find, were they labeled?

I feel a lot more at ease now knowing what to look for and what to expect.

Mr. Intheburbs, I checked for Z82 and it wasn't listed, Z85 was but no Z82....time to get out the flashlight on look for some hidden wires...

Thanks for everyone's help. I'll let you know how it goes.

bruce69camaro · March 13, 2014

Forgot to ask, are these over-sized 40a fuses referred to as Bussmann Maxi Blade Fuse?

woodm · March 14, 2014

Bruce,

The loose wires in the engine compartment were not difficult to find at all in my case. Once I removed the plastic housing surrounding the fuse/circuit box the wires were in plain site. Look for the red and/or blue wire, possibly below and to the right of the fuse/circuit box in the engine compartment. These wires may be tucked under the box itself and/or may also be wrapped/bundled and tied together (according to some other information sources I have found). None of the wires in my truck were labelled.

I believe the large fuses we have been mentioning are referred to as maxi-blade fuses.

Good luck with your project.

bruce69camaro · March 14, 2014

Thanks again Mike and to everyone else that helped out.

Now if we can get back to the 50F weather, I'll be able to go out and get this job done.

bruce69camaro · March 14, 2014

Woodm, I found the red and blue wires up front, not a problem, but I got a small problem.

At the 7 pin, I got a black, white, blue, green and yellow wires, it looks like there is a wire that was cut but can't tell the color.

I take this would be the wire that goes to the blue wire up front?

Is this what you found as well?

woodm · March 14, 2014

Bruce,

You have accounted for 5 wires, there should be 7 in total at the 7-pin connector. Do not assume anything here.

This is where you need to be especially careful. There should be a brown wire attached to the plug which powers tail/running/clearance lights on the trailer.

There should also be an additional wire to power reverse lights on the trailer, if equipped. In my case, this wire is purple in colour and connects to the centre pin of the 7-pin connector.

When I reached this point in the project, I cut all wires to the 7-pin connector, stripped off a half inch of insulation from each, then hooked up my test light and tested the function of each exposed wire. I did not feel comfortable that the 7-pin connector had been wired properly in the first place and therefore felt it necessary to confirm the function of each wire. My suspicions proved correct as one of the wires (light blue in colour) is actually used to power a CHMBL (centre high mount brake light) and should not have been wired into the 7-pin connector at all. (This explained why my trailer brakes were locking up each time I applied the brakes in my truck...the PO had mistakenly used this wire to power the trailer brakes!!).

Do not assume that the blue wire you have found at the 7-pin connector is the correct one for the trailer brakes...test, test, test. Logic would suggest that if you have found a blue wire (medium blue in colour) in the engine compartment that is not connected to anything and this wire is the power output from the brake controller in the cab then, in all probability, the trailer brakes are not wired correctly at the 7-pin connector.

Again, careful and detailed testing of all wires entering the 7-pin connector is essential.

One thing you might consider here is to purchase a new 7-pin connector, complete with wiring/installation instructions, from your local auto parts or trailer supply store. Proper testing of the wires entering the connector and careful review of the installation instructions provided should ensure that that you are able to connect the wires correctly in the 7-pin connector.

In my case, in order to hook up the trailer brakes, I had to run a separate new wire from the engine compartment to the rear of the truck (zip tied to the existing harness). I then connected the loose medium blue wire found in the engine compartment to the newly run wire and connected the opposite end to the appropriate pin in the connector at the rear of the truck.

Hope this helps.

Mike

bruce69camaro · March 15, 2014

Sorry let me make a correction, I have yellow, dark green, light green, brown and white.

Brown is for lights, yellow is left turn, dark green is right turn, white is ground.

Light green is backups which I'm not using so I won't connect.

I need to run a 10a blue back to #1 terminal and that should do it, I hope.

I found a wiring diagram showing these colors and their location.

My only question now is, #3 is for 12v, I was told I do not wire this if I'm not needed any power supply to the trailer for lights???

I'm now using terminals 1,2,4,5,6 on the plug. Hope this is right?

woodm · March 15, 2014

Sounds like you have a handle on things Bruce. You are correct regarding the 12V pin...if you do not have any need for auxiliary power, then you can ignore this pin.

Happy trailering!!

bruce69camaro · March 17, 2014

I got things hooked up but still need to get the brake controller yet BUT I do have power back to the plug and while I was at it ran the brake controller output wire back to the plug, so I hope everything works out?

Thanks for everyone's help.

Bruce