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Fuse Anomaly with Igloo Cooler and Tire Inflation Question

I have an Igloo Cooler which plugs into my vehicle’s cigarette lighter outlet, which is governed by a 20 amp fuse. The cooler has performed superbly over the years, until this year when it immediately blew the 20 amp fuse and then a 25 amp fuse on my auxilary power outlet. The people at Igloo suggested that sometimes sudden power surges from the vehicle itself occur and that this would be shown to be a likely cause of my problem if the Igloo still performed with the same power cord plugged into a converter that uses household current. We tried this and the Igloo worked through the course of an entire night.
The mechanic at my auto repair shop, investigating the problem, came to the conclusion that I needed a new Igloo. He had plugged the Igloo into his own vehicle and it repeatedly blew the fuse. Imagine my surprise when I took the plug of the power cord apart and discovered that it contained its own 5 amp fuse and that this fuse was intact! Can you explain the anomaly of a cooler blowing 20 and 25 amp fuses while leaving a 5 amp fuse intact, and if so can you suggest any way of continuing to power my Igloo from my vehicle?

Second question (unrelated): My tires recommend inflation to 41 psi, whereas GM, inside the driver’s side door, recommends inflation to 35 psi. Whose recommendation should I follow?

Can you replace just the cord for the cooler? It sounds like there’s a short in the plug.

Follow the sticker on the door of your car as far as tire inflation.

Tires are used on many applications, so the tire manufacturer cannot know what is correct for your vehicle. All the tire manufacturer puts on the sidewall is the maximum pressure beyind which the tire could become unsafe. The car’s manufacturer puts on the doorjam and in the owners’ manual the correct pressure for the individual vehicle. Use the doorjam-specified pressure.

+1 to mountainbike’s explanation, but I want to point out something else to the OP.
As mountainbike stated, the pressure listed on the tire sidewall is the maximum pressure as per the tire manufacturer, but for some reason, the OP seems to think that this is the tire manufacturer’s “recommended” pressure. There is a significant difference between “maximum” and “recommended”!

Think of this in human terms for a moment.
Imagine that your doctor tests your blood pressure and finds it to be a bit higher than normal. He/she then tells you that your BP should be monitored regularly, and that if your blood pressure goes above…let’s say…150 systolic (upper number), or above 90 diastolic (lower number), you will have to go on medication.

In other words, the MD is saying that your maximum BP should be considered to be 150/90.
Does that mean that your doctor is advocating that type of blood pressure?
No!
Those pressures represent a maximum, but not a desirable blood pressure.

Use the tire pressure listed on the placard affixed to the door jamb of the car. The vehicle manufacturer has done extensive testing and found that pressure to be a good number for decent handling, ride, braking, and overall safety.

As for your cooler problem, sounds like a short somewhere, do as @Bisbonian suggests. The fuse blowing in the car/not in the cooler cord would indicate there’s a short before the cord fuse.

the number on the tire is the max. pressure thgat the tire is rated for. use the rating on the door of your car

Cut off the male lighter plug and replace it with a quality (hard to find) plug…The cheap ones are poorly made and tend to fall apart or short out, as you have discovered…

There’s also the possibility that the cooler is fine while drawing few amps and the real problem is in the car’s electrical system. Maybe the cooler current draw is nothing more than the tipping point for popping the fuse.

The lighter circuit is often tied in with wiring that winds its way all around the car with various other items tied into the same fuse. The cooler wiring should be simple enough that a VOM would detect a short in a minute.

Imagine my surprise when I took the plug of the power cord apart and discovered that it
contained its own 5 amp fuse and that this fuse was intact!

This is puzzling. If I’m reading your description correctly, you’re implying the cooler will blow a 20 and/or a 25 amp fuse, but it’s not blowing a 5 amp fuse located in series in the power cord. Maybe I’m not understanding your description correctly.

Was that 5 amp fuse part of the 12-volt wiring? Or was it part of the 120-volt circuit that you mentioned?

Thanks to all of you who set me straight on the difference between a tire’s inflation recommendation and that of the vehicle manufacturer. As for my Igloo problem, thanks especially to Bisbonian, Texases, Caddyman and OK4450 for suggesting there must be a short in the plug of the power cord which blew my vehicle’s fuses before the surge of current could blow the power cord fuse. I had on-hand a power cord from a discarded appliance, cut off the plug of the Igloo cord, and spliced the wires together. My Igloo now runs off my vehicle’s power outlets without blowing a fuse and I am happy that it has been restored to usefulness.

The only thing that a few pounds over overinflation will get you is,a bit more mpg and a little more load capacity,usually with a trade off for handling and the center of the tire will wear a little faster and the ride will be a bit harsher.I usually run my pickup tires a bit overinflated(they seem to handle a load better and better MPG(a severly underinflated tire will fail spectacularly after a bit-check your spare from time to time)-Kevin

The issue you are having is the same issue I once had with a satellite radio power cord. The issue ended up being in the power cord. If you can replace the cooler’s plug (the male piece that fits into the power outlet), it might solve your problem.

The value listed on the side of the tire is the maximum rating for that tire. The PSI value listed on your car door, and in the owner’s manual, is the recommended tire pressure for ALL tires used on that car, regardless of what is written on the side of the tire. Well, not totally regardless - you need to make sure the value on the tire is greater than the value on the car. However, you should only inflate your tires to the recommended value of the car.