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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 5559
Experience:  Owner at DJ Wilson
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Have a GMC C7500 medium duty truck in the shop customer

Customer Question

Have a GMC C7500 medium duty truck in the shop customer brought it to me because it was not charging. I tested the alternator and found that it was not charging and Both batteries tested out good as well. I replaced the alternator and still not charging and the small excite wire on the alternator is not getting power so it is not telling the alternator to charge. I checked all the fuses that I could find plus all of the inline ones as well. I am in need of some more Ideas thanks.
Submitted: 11 months ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 11 months ago.

Hi my name is***** you still need help with this?

Customer: replied 11 months ago.
Nope I got it thanks for getting back to me tho
Customer: replied 11 months ago.
One other thing tho do you by chance know anything about trailer abs on a semi trailer?
Expert:  Daniel Wilson replied 11 months ago.

Hi there. I could help you with that. What troubles are you having and do you have the fault codes by chance?

Customer: replied 11 months ago.
Well that's the problem it is not reading the abs at all it's a wabco system and it won't read and the light won't come on and go out
Expert:  Daniel Wilson replied 11 months ago.

Hi, Sorry for the delay. I got called out on the road for an emergency. Verify your powers and grounds to the ABS ECU to see if this is why it wont do a flash code. If there is power and ground but not functioning and the harness checks out okay the ECU is bad. Check for corrosion and damage in the harness and for power/ground at the module. click on these links for help.

Troubleshooting 1

Troubleshooting 2

Customer: replied 11 months ago.
We have replaced the ECU already have new wiring ran and the abs light just come on really faint and the system does not click acts like the is no power there we have tired to run power direct from a battery as well