Hello,


I'm the original owner of a 2004 Saturn Ion 1 sedan. About two weeks ago, the dash displayed a "Coolant" warning on the dash. The coolant tank and level look normal. I checked the fuse box in the engine compartment and found that fuse #10 is blown. I replaced the fuse, and it blew again. According to the GM wiring diagram, there are 5 things on the circuit (picture attached). I jumpered the coolant reservoir wires with a paperclip and replaced the other 4 components. The fuse is still blowing when replaced. Any idea what's causing the fuse to blow?

Thanks in advance!
Fuse #10 with attached components identified.

 

If a fuse blows, it's most often because of excessive current in one of the associated circuits. And not nearly as often as a fault with one of the components themselves. It sounds more like one of the wires is shorted. If you trip a circuit breaker in the home that controls a lighting circuit, do you replace the bulbs as the first step in troubleshooting? You need to inspect the wiring going to those four components. A prime suspect is the wiring to the Evap Canister Vent Solenoid, which is way back under the car near the fuel tank/pump. Look closely at the wiring harness where it bends around body components, or is close to the exhaust system.

 

First, thanks for the reply and suggestion. The parts I replaced were inexpensive so I figured I'd try that first, sometimes you get lucky. I haven't made a car payment in 16 years, so I don't mind throwing a few bucks at the problem. I feel like chasing down a shorted wire in my wiring harness is going to be a real chore. I was just hoping there was something else I could try other than that. The car is 21 years old and although I've taken good care of it, the wiring harnesses have deteriorated over time. The OEM plastic flex conduit and electrical tape holding that conduit in place has all but flaked away over the years.

Thanks!

 

You need to check the resistance of each leg and find the one that is shorted.

 

I would think if one of them are shorted, you will get a check engine light with a p code telling you which solenoid or oxygen sensor is not behaving properly. Is your check engine light on?

One of the issues with shotgunning parts is that you just introduced 4 additional variables into the equation. You don't know that they're all good. Some could be DOA, where as the ones already pressed in the circuit may all have been fine.

Is that paper clip resting on anything metal under the hood? Because if it is, you may be grounding and shorting things that way.

 

We use a circuit breaker in place ot the fuse and start unhooking things. When we unhook the bad one the breaker does not kick out and we go from there.