2003 Chevrolet Impala 3.4 liter

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Joined: Tue Aug 29, 2017 8:33 pm

2003 Chevrolet Impala 3.4 liter

Unread post by Culpiesr2 » Tue Aug 29, 2017 9:29 pm

Hello, I Am Looking For Help Diagnosing My Impala's Illness. About A Week Ago, my car overheated on the way home from a short trip. I Assumed it must be the thermostat stuck closed, so I Replaced it. Car Still Overheats. So I Replaced Water Pump. Car Still overheats, and Fan Does Not Come on, So I Replaced Fan. Fans Still do not come on, and horn does not work. I Took bottom horn off, (there are two) and tested it....BEEEEEP....Horn worked. Put Horn Back on, Took car to auto repair shop, and asked them to do an engine diagnostic check, which I thought meant they would hook it up to machine which would find short, etc. They used hand held scanner, and found no issues, but offered to fix my car for 495.00. Nice Guys. I brought car home, and checked it for short by pulling each individual fuse, using test light. No Bad Fuses Found. I am at a loss as to what the problem may be. with no horn, there is no beep when I lock my car, but lights flash letting me know its Locked. Also when I Hit Alarm button, lights flash but no horn. Please help me decipher this issue, as my car is upset I Haven't been driving it lately. ( And so is my boss lady.) There are no leaks (Visible), no dash indicator trouble lights, and I've never had any trouble with car prior to this. Any help would be appreciated. Thank You For Reading This, And Thank You For Having A Page like this where People can come to get advise from those who know more than we do.

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Re: 2003 Chevrolet Impala 3.4 liter

Unread post by carriedi » Sat Sep 16, 2017 2:57 am

so is your car still overheating?

you have two cooling fan fuses and three fan relays in the underhood fuse box. there are tools that allow you to jump the relays to see if the fans will turn on. Using a scanner you can see if the car's computer is signalling the relays to turn the fan on and what temperature it sends the signal at. the computer (powertrain control module) looks at the engine coolant temperature and when it sees the temp. at a certain temp will send a signal to turn on the radiator fan on. you have to check to see why you aren't getting the fan circuit to turn on the fan. Could be the sensor, could be the computer, could be the fuse box, could be the relays, could be the fans, could be the grounds for the circuits. there are a lot of checking that needs to be done.

As far as I know, I have not seen a machine you can hook up your car to that will tell you if and where you might have a short at. You may not even have a short. Most times if you have a short you will blow a fuse. Short to ground means that the circuit will pull more amps through a circuit than the circuit is rated for so it will blow the fuse that protects the circuit.

Does the horn work when you push the horn switch on the steering wheel? The horn is turned on by the horn switch or the body control module. Both the switch and the BCM ground the horn relay, in the underhood fuse box, to turn on the horn. Have you checked the horn relay?
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