10-amp fuse blows when I turn on the A/C

JHAGAN5216

MEMBER
2005 RAM 2500
6.7L
TURBO
2WD
AUTOMATIC
300,000 MILES

My truck listed above has a Cummins diesel engine, 24 cylinders.
I actually have two problems. The ABS and brake lights are on, on my dash.
When they come on, my air quits working. The air on that truck has never worked right.
And if and when I turn on the air, when I turn on the A/C, its 10-amp fuse instantly blows. The 10-amp fuse is for the A/C clutch
I have read this means a short circuit, rather than component failure.
On my dodge, everything is run through the ignition. This causes a continual electric flow through the wires behind the driver knee panel.
The constant draw melts the wires. A TSB for a vehicle a few years older than mine was for the exact same things that I was experiencing. The TSB said the ac had to be taken off of the ignition, rewired into its own wiring harness, and given its own relay, which was to be mounted on the brace for the emergency brake.
The Dodge dealer half-assed the repair twice. Even though the manufacturer was going to provide everything and pay for everything.
Why didn’t Dodge fix it before they sent it out?
So, I feel fairly certain all these problems stem from the A/C and ignition being on the same fuse.
Will Dodge send me a harness, or is this something they require a dealer to do?
At this late date, would they even bother.
I guess you could get the wire yourself.
The pre-made dodge wiring harness is all color coded.
Thank you

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

Couple things just to clarify. This is a 5.9L? You mentioned this is a 6.7L which is the new engine but that was not available on the 2005. Also, you said 24 cylinder and you meant 24 valve? I just say that so that others will not be confused or comment that this was wrong. People on the internet have a need to correct people and they are not always the nicest about it.

Do you have the TSB number and I am happy to review that?

As for if Dodge will send you anything, the answer is no. Unless it was a recall, they have no obligation to fix the issue as the TSB is nothing more than an aid to help diagnose these concerns correctly the first time.

This means there is no defect in the product, but they have seen where a number of them have similar/same issue. This is no different than any other product like a microwave that the door seal leaks. This is a common failure but that doesn't mean the company has to fix all of them for free. There is a tester, and they will sell you a seal if it is leaking. As a consumer, I don't like it either but unfortunately that is how things are.

As for your issue, the fact that the fuse only blows after the AC Is turned on then that points to the clutch as you noted as the issue.

Most likely it is shorted as you said but the wiring is most likely not the issue. More than likely it is the clutch itself that when it engages the coil is shorted to ground and it blows the fuse.

https://www.2carpros.com/articles/how-to-check-wiring

We can do this a couple ways, but the best would be to test the amperage the clutch is drawing. It is going to be more than 10 amps so if it were me, I would look to replace it. Also, you can ohm out the wiring and load test it to see if when unplugged it blows the fuse when trying to light a light bulb.

So, this means unplug the compressor and use the power and ground terminals of the connector to power a light bulb when you turn the AC on. If the lamp lights and does not blow the fuse, then the clutch is the issue.

I attached the wiring diagram below so let's start with this and go from there.

Thanks

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10-amp fuse blows when I turn on the A/C

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