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Dan, Technician
Category: Chevy
Satisfied Customers: 23985
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
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2005 Silverado cooling fan not coming on checked all the

Customer Question

2005 Silverado cooling fan not coming on checked all the relays fan mortars are good think it's the PCM changed it out with a used one from the exact same truck won't start with it in.
JA: How many miles are on the car? Has the car been starting normally?
Customer: 230000 drove it every day never any problems air won't work now because fans won't come on.
JA: Are you fixing your Silverado yourself? What have you tried so far?
Customer: Changed out relays that didn't work getting power to them checked the tCM changed out the PCM with a used one exact same won't start with it
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 7 months ago.
Category: Chevy
Expert:  Dan replied 7 months ago.

Hello, my name is ***** ***** I'm here to help get your problem solved.

Expert:  Dan replied 7 months ago.

PCM needs to be programmed to vehicle at dealer for it to work. What engine do you have? I'll tell you how to test wiring to make sure PCM is problem.

Customer: replied 7 months ago.
Expert:  Dan replied 7 months ago.

If you ground the dark green wire at pin 42 of connector 1 at PCM this should turn on low speed fans. If you ground the dark blue wire at pin 33 of connector 2 this will turn on high speed. If both work when grounding wires you know PCM is the issue. Dealer will charge around $100 to install and program. Let me know if you have more questions, thanks.

Customer: replied 7 months ago.
I will try that. if that doesn't work do I have to pay again for same question
Expert:  Dan replied 7 months ago.

No, you can reply back to this answer at any time without additional fees so make sure to keep me updated. Thanks!

Customer: replied 7 months ago.
Ok thanks.
Expert:  Dan replied 7 months ago.

No problem, let me know how it turns out. Thanks again and have a good evening.