# Car runs rough and blows fan fuse at idle and low speeds



## Eddy Cruze (Jan 10, 2014)

Could be a bad battery cable which could be fixed under special coverage. Is it doing anything else electrically related?


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## jthiessen3587 (Aug 9, 2017)

I have had the check electrical system screen randomly pop up a few times. Lights have dimmed in and out while driving but that hasn't been happening recently. I did look at that sticky about the cable but haven't had any of those symptoms.


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## ChevyGuy (Dec 13, 2014)

When I get a chance, I'll have to look up J30. Too much current is a major clue. My first thought was bad fan, but it seems you've replaced it already.


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## jthiessen3587 (Aug 9, 2017)

ChevyGuy said:


> When I get a chance, I'll have to look up J30. Too much current is a major clue. My first thought was bad fan, but it seems you've replaced it already.


Yes I did unfortunately. The day after i threw away the other fan I found out it wasn't the issue. My gut is telling me that the AC condenser is bad and is shorting out the system. When in idle it feels like the compressor is engaging and then the car shakes a bit and can hear the fan blowing real loud like a get engine for a few seconds.


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## ChevyGuy (Dec 13, 2014)

jthiessen3587 said:


> My gut is telling me that the AC condenser is bad and is shorting out the system. When in idle it feels like the compressor is engaging and then the car shakes a bit and can hear the fan blowing real loud like a get engine for a few seconds.


A condenser can't "short out". There's nothing electrical about it. It might be plugged which could create some fun. But a blown fuse wouldn't be one of them. "Jet mode" does suggest the A/C pressure has gone sky-high. 

Having a A/C shop look at it seems like a good idea.


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## jthiessen3587 (Aug 9, 2017)

Shop update:

So took it into the shop today and they said the pressure switch is needing to be replaced. It's causing the fan to go on and off instead of running consistently to keep engine cool. He is thinking when the fan kicks on hard like that its causing the fuse to blow. He also said one of the spark plug wires were loose making the car run a bit rough.

Once I get my car back I'll confirm if that fixed my issues.


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## ChevyGuy (Dec 13, 2014)

jthiessen3587 said:


> So took it into the shop today and they said the pressure switch is needing to be replaced. It's causing the fan to go on and off instead of running consistently to keep engine cool.


That's happened to a few people. Not common, but it's happened.




jthiessen3587 said:


> He is thinking when the fan kicks on hard like that its causing the fuse to blow.


It would place maximum stress on the fuse, but it shouldn't cause the fuse to blow. You might verify it's the right sized fuse. 




jthiessen3587 said:


> He also said one of the spark plug wires were loose making the car run a bit rough.


The sparkplugs can work themselves loose. Usually the clue is a "chirp" or "click" from the gasses escaping combustion. But the proof is in the fix.


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## jthiessen3587 (Aug 9, 2017)

UPDATE:

After all the work is done the AC was still not working correctly. It turns out that a diode on the replacement fan was not working correctly which controlled the fan while the AC was on. Since it wasn't working the fan was coming on real loud for a few seconds and turning off. Napa Auto Parts warrantied it and got me a new one and it's finally out of the shop and running great again. 

So in the end it was the replacement fan and probably a loose spark plug cable causing all my issues.


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