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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29430
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Chevy

Chevrolet Silverado 2500 HD LT: service trailer brake system

service trailer brake system message on
Submitted: 5 years ago.
Category: Chevy
Ask Your Own Chevy Question
replied 5 years ago.

GM Tech (Cam) :

Hello, I'm Cam. Please include all the details about your issue so I can accurately advise you. I cannot see your vehicle so please be detailed.

GM Tech (Cam) :

HAve you done any repairs recently under the dash or at the back?

GM Tech (Cam) :

Any other warnings?

GM Tech (Cam) :

and those codes, Do they have a 0 after the C

Customer:

yes on o I just got truck no idea if any other work been done

GM Tech (Cam) :

ARe you certain of the code numbers? They do not seem to match up to any in the manual .

Customer:

how bout c1116,1117,1118

GM Tech (Cam) :

looking

GM Tech (Cam) :

yes!

GM Tech (Cam) :

That is for the manual switch in the dash panel. Can you check the wiring and connection to it?

GM Tech (Cam) :

When the manual apply switch 5-volt reference circuit or TBCM ground is open circuit, in addition to setting DTC C1116, DTC C1117 and C1118 may also be set as current DTC. In this case, diagnose the apply switch 5-volt reference circuit or TBCM ground first for open circuit fault before to diagnosing DTC C1116. If there is an aftermarket trailer brake controller, the ITBC must be disconnected. Do not power both ITBC and aftermarket controllers to control the trailer brakes at the same time

GM Tech (Cam) :


Circuit/System Testing

Important: All electrical components and accessories must be turned OFF and allowed to power down.



1. Ignition OFF, disconnect the harness connector at the trailer brake controller switch panel.
2. Test for less than 5 ohms of resistance between the ground circuit terminal 8 and ground.

◊If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the TBCM.

3. Ignition ON, test for 4.8 - 5.2 volts between the 5-volt reference circuit terminal 3 and ground.

◊If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TBCM.


◊If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the TBCM.

4. Install a 3A fused jumper wire between the signal circuit terminal 4 and the 5-volt reference circuit terminal 3. Verify the scan tool Manual Apply Switch is greater than 90 percent.

◊If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TBCM.

5. If all circuits test normal, test or replace the trailer brake controller switch panel.

Customer:

if wiring good , mean switch bad

GM Tech (Cam) :

Possibly, do you see the note about the 3 codes being set and the 5V reference?

Customer:

yes sorry

GM Tech (Cam) :

no problem at all.

Customer:

thanks I will try

GM Tech (Cam) :

Is there more I can get for you?

Customer:

not now thank you

GM Tech (Cam) :

Please reply back if you need additional help or press ACCEPT If my answer was helpful. You can reopen it at any time by replying to it and I will answer ASAP. PLease keep in mind that as experts on this site, we are only compensated for our time spent helping customers once ACCEPT is selected. Be sure to bookmark this page (CTRL D) to reply with results or ask more if you need. Thanks again for using Just Answer. Cam.