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Gary
Gary, ASE Certified Technician
Category: Chevy
Satisfied Customers: 742
Experience:  Senior Technician
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My terminating resistor on 09 silverado is testing at 119.5

Customer Question

My terminating resistor on 09 silverado is testing at 119.5 ohm is that ok
JA: What is the model/year of your Chevy?
Customer: 09silverado 4.8 litre*****
JA: Besides this, what condition is the car in?
Customer: Excellent shape
JA: What year is your Chevy?
Customer: Abs stabiltrak abd brake warning lights are on in dash
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Traced most wiring and replaced abs module
JA: Anything else you think the mechanic should know?
Customer: Tried adding external ground for battery with good jumper cables as i see a negutave battery cable issuewith these trucks
Submitted: 4 months ago.
Category: Chevy
Customer: replied 4 months ago.
If i test between ports 6 and 14 i belive it is u get 120.5 and i know that is not supposed to be over 60 dont know where else to look
Expert:  Gary replied 4 months ago.

Hello there,

If you have 120 ohms across 6 and 14, one of the pair of resistors or wiring in one direction is open circuit.

I'll come back to you soon with some more info and a circuit diagram.

Can you leave your meter across 6 and 14, then disconnect X1 at the ECM.

If the 120 stays on the meter, the other direction is ok, and the fault is towards ECM. Vice Versa for if you lose the 120 ohms on your meter when you disconnect the ECM.

Gary

Customer: replied 4 months ago.
I hooked meter up last night and tried wiggle test with wires and if i unhooked the resistor at back of truck by the spare tire it stays the same
Expert:  Gary replied 4 months ago.

Hi again,

I'm glad you found that end, it shows on GM SI as after the Trailer Brake Control Module.

Can you see the wire colours at that point, should be TAN and TAN/WHITE.

Can you then measure the resistor you took off, hopefully open circuit.

If it reads 120 ohms, then place a short across the pins in place of the resistor.

Go back to 6 and 14. Technically it should be read a short now.

So either the resistor is open or or one wire from the ALDL 6,14 to the back of the vehicle is open circuit.

Gary

Customer: replied 4 months ago.
Resistor isolated from harness ohm out at 119.5 as fat as wire color not for sure but will place a short there and ohm between post 6 and 14 latter this afternoon how does one ohm the resistor in engine computer?
Expert:  Gary replied 4 months ago.

Ok, the rear resistor is fine.

Leave it off, and measure at 6 and 14.

If it reads open circuit, you were looking at the rear one only earlier from 6 and 14, meaning towards the front is open.

With the rear one off, if you are still 120 at 6 and 14, the front is fine.

The ECM resistor is non-serviceable.

Gary

Customer: replied 4 months ago.
With rear on removed i get 119 across pin 6 and 14
Customer: replied 4 months ago.
With rear one removed and meter across 6 and 14 124 ohm when i remove j1 plug from compter it opens
Customer: replied 4 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Gary replied 4 months ago.

Hi there,

I can't do phone call request, sorry.

But you proved all forward of the ALDL to the ECM is fine.

Your rear resistor is also fine.

The pair going to the back has an open on one wire of the the pair.

You can prove this with your meter, one leg of the meter in 6 the other leg to either wire at the back should see Zero ohms on one wire.

Same for 14, zero ohms on the other wire.

Can you now measure these two wires?

https://gsi.ext.gm.com/image_en_us/gif/000/002/064/2064945.gif

Gary

Expert:  Gary replied 4 months ago.

Hi again,

How did you go with the continuity test?

I hope my advice has been of assistance to you.

Kind regards

Gary