What can you teach me about fuses?

Maintenance/Repairs
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Hi, I’m female. Took Auto Mechanics 101 back in the dark ages when I was young because I saw my mother get ripped off by mechanics and she never understood what they were talking about. So I know the basics.

I have driven nothing but Toyotas, either used Camrys or a used Corolla, for the past 8 years.
Just got a used 1999 Camry for a great price. Knew it needed some work but based on
the vehicle history, which I checked at Autocheck dot com, I felt comfortable with what I was buying, the potential repairs needed, and the price of the vehicle. Plus my budget was very limited so I had to stay within budget.

The power door locks suddenly stopped working along with the little light around the key ignition, and the dome light didn’t work at all, so I began to wonder if that could be a simple fuse issue. Found the owners manual online (thanks whoever uploads those) and found the fuse diagram. After studying which fuses control what I took out the two remaining spares, inserted them, and voila!, I now have power door locks, a dome light, and the keyhole light again.

I feel very smart now.

So my question is, could a fuse also be causing the car to not start up right away? A Toyota specialist told me it was probably some valve thing that’ll cost $450 but could it have something to do with the fuse that controls the starter?

The car also has a thermostat issue. Not overheating, but if I drive on the freeway for any amount of time it drops down to very cold. Driving in town it’s at the halfway point, which I know it normal. Mechanic told me it’s a bad thermostat but could that also be fuse related?

Secondly, is dumb to just go buy some new fuses for these areas, try them, and see if that fixes it?

Third, the car has an ancient CD changer in the trunk. If I go get some info from YouTube can I remove that by myself? Can I just cut those wires to the CD changer and its controller or is that stupid? Will doing that somehow mess up the electrical system?

Thanks! Love my new/old Camry. High miles and still drives like a champ.

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Glad you are trying to figure out how to take care of your car. When you say ‘causing the car to not start up right away’ what do you mean. Does the starter crank but the engine not start or is there silence? Tell us more about what happens for us to help you.

A fuse is like a one time switch, it is either on and allows electricity to flow or it is blown and nothing happens until you replace it. Your starter issue does not seem to be a fuse.

This link gives an overview of what fuses do. http://auto.howstuffworks.com/wfc2.htm

Sounds like your mechanic is giving you good advice,. The thermostat does not use a fuse

Do not randomly start cutting wires to the CD changer. If you are unfamiliar with a fuse, you will struggle with the wiring and may make things worse. If the CD changer is not giving you any trouble, leave it alone until you can learn more or get someone who is familiar with car electronics to take it out…

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I assume those two happened to have the same amp ratings as the ones they replaced.

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From the sound of it, you definitely need a new thermostat. Suggest replacing it, along with the coolant.

Please define “not start up right away?”

I believe your mechanic is leaning towards low compression, due to tight valve lash. Has he actually performed a compression test, or did he just throw that out there, so to speak

It could be many things. Such as a fuel pressure problem, for example. Teeing in a fuel pressure gauge would quickly answer that question

Ebay is a good place to buy used owner’s manuals cheap. You might want to buy a Chilton or Haynes service manual at your local auto parts store. Or you could probably find the factory service manuals . . . including the electrical troubleshooting manuals . . . on ebay for a reasonable price

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If you want a new radio, check out crutchfields, There are often components that are needed they will suggest, vs buying a radio at a box store.

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Fuses are installed in the electrical circuit to make sure the wires don’t catch fire if a hot lead (battery +) touches bare metal, or ground, in some way. They contain thinner wire than what they are trying to protect so THEY burn up in that tiny little space rather that the wiring. They are either blown or not. There is no in-between. That said, they only apply to electrical things. The thermostat is not electrical, it is mechanical, and I agree with @db4690, sounds like you need a new one.

As for the “start up right away” those things could be electrical (ignition) or mechanical (engine compression) or fuel related electro-mechanical. No fuse is going to cause or fix any of these problems since the car is starting and running. If the starter is spinning the engine, a fuse is not the answer.

The CD player is a simple accessory. It likely has a plug for the wires. Unplug the CD changer - they usually have a little plastic tab that locks the connector you need to pry-away a little - and take out the CD. If, for some wild reason Toyota has the starter wired through the CD changer (they don’t!) you can plug it back in if the rest of the audio system stops working (it won’t).

A Haynes or Clymer or other service manual, if you want to continue to learn about your car, is a great thing to have. It tells you how things work and where they are and how to fix things or at least understand why the mechanic says “we need to remove the engine to fix that.”.

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The fuses you use have to have the same amp rating as the ones that were blown. If you use a lower rated fuse it will probably blow quickly. If you use a higher rated fuse the wiring can get hot enough to burn. Trust me, you do not want to be inside a car with an electrical fire.
The thermostat needs replacing. Google " replace thermostat on a 1999 Camry and you should find a U-tube video.
You don’t really know how to do anything on a car because you can find iy on U-tube. He then asked me how did you find out stuff when you started. I told him it was called Motors Repair Manual. It put the Chilton’s and Haynes manuals of today to shame. It was very expemsive but every public library had some, You just read the text, stared at the pics and at your car until you realized what the were showing you.
Old ones are still sold today at old car swap meets.

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You’ll need to give us a lot more information on your starting problems. Tell us everything that happens.

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Here’s one I inherited from my Dad.

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For your CD changer, are you wanting to remove it permanently to give yourself more room in the trunk?

It depends on how it was installed how easy it will be to do this safely, but in the abstract, most CD changers do not involve a great deal of power use. Oftentimes there’s a fairly thick cable going into them that carries both the power wire and the cable that transmits the sound to the amplifier. Usually it’s safe to just unplug that cable. If you want to be really careful you could cap off the plug with electrical tape once you do this.

However make sure it’s a CD changer and not an amplifier, as amps carry quite a bit of power - I’ve seen cars set on fire when the amp power wire develops a problem. An amp should have a very thick wire running from the battery to the amp, and within a few inches of the battery should be what’s called a fusible link, which will be a thick, hard plastic part of the wire. Unscrew that and remove the fuse, and you won’t have a live wire anymore.

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I agree Motors manuals much better than Chilton and Haynes

Their labor times manual was also more comprehensive, and more accurate, IMO

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Hi, sorry for taking so long to read and respond to these. Holiday season. Busy. Anyway, the CD changer is a Pioneer unit - after-marekt install. I will not attempt to take it out myself. It’s on my to-do list of repairs as soon as I can afford it.

Only the front speakers in the car work and only the front right does not have an annoying buzz coming from it, so I feel certain something was wired wrong when they installed the CD changer and someone competent will have to put it all back to how it was originally.

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Here’s the starting problem: First start of the day, and only the first start, it will not turn over. Starts and dies. I hold the accelerator down (lightly) to give is a steady stream of gas to keep it running for about 2-3 minutes, then it can be shifted into gear and driven.

It only does this the first start of the day. Rest of the day, even after sitting for 7 hours, it will restart fine. It’s not the cold. I don’t live in a cold climate.

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Yup. I went to the auto parts store and got some new fuses.

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Thanks - I’m going to have to look around and see if it plugs in anywhere.

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You know what’s frustrating about now learning about fuses and diagnosing the issues myself? I owned a different Camry a few years back. High miles but as trustworthy as could be, even in -30 weather. It had some issues which I could never afford to fix and now I wonder if someone had simply told me to try replacing some fuses, if that would have fixed the problems?

E.g. my back-up lights didn’t work on that other car. No one ever suggested to try replacing the fuses and I took that car to independent shops and one dealer. Part of the fan system for the A/C and heat didn’t work. Everyone I ever talked to about that issue wanted $750 just to take the dashboard apart and look at the switches inside. They never said, “Start with replacing those 20-year-old fuses.”

Now I’m reading that fuses don’t necessarily have to burn out completely to reduce power or stop a component. They can just be corroded to cause connectivity issues. After 20 years I think it’s fair to expect a little corrosion on some parts, don’t you? Anyway, it’s sad to know mechanics don’t suggest these things as little maintenance issues that can be tried first for $1.00 a fuse. I actually think that’s because so many people don’t hold onto or buy old cars anymore. I think a lot of mechanics are not used to seeing anything more than 10 years old nowadays, at least in the places I’ve lived.

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The next time you are in traffic look around and you will see old vehicles. The same goes for used vehicle dealers that are not on Rodeo Drive.

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Your recent insight is exactly right. While some things we use often are very complex and have only a few owner serviceable parts, it’s truly amazing just how many things you can fix by yourself on cars and really on home appliances, too.

Your CD player in the trunk has two or three cables plugged into it. They carry power, control wires and speaker output wires. If you follow those cables to the back of the player you may well find that they have snap together connectors. Like someone said, those connectors often have a system that keeps them together, and that you have to press against a piece of plastic to release a catch to unplug them. Look at one carefully with good light and maybe a magnifying glass and you should be able to figure it out. If you unplug it and nothing bad happens, great. If something stops working that you want to have work, plug it in again.

Small appliances are simply tossed when they start to become unreliable, and I have found that very often they just need a new cord. The wires inside the insulation break after years of being bent and wound up and stretched. If you explore the thing that’s not working (unplugged from the wall!) and maybe unscrew the bottom cover, you can often see what to do next. If it was already broken and didn’t work, and you break it some more, so what?

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Fuses are installed in the car’s wiring to protect against a short circuit – due for example to a wire’s insulation getting chaffed and exposing the copper wire. That kind of short circuit could heat up the wire enough to start a fire inside the car. That’s one major reason for the fuses,your safety. So don’t take them lightly. When one fails, try to determine why it failed, chaffed/broken wires etc, and only replace it with the same amp rating.

When a fuse blows it causes that circuit not to conduct electricity is all. So whatever function that circuit was for will no longer work. It might be a function you don’t use, so if a fuse blows, you might not even notice. Sometimes a fuse can fail in an intermittent way, but that’s a uncommon failure mode. For that, usually best to use a shop to diagnose it for you.

Look carefully at a fuse; you’ll notice there’s a subtle metal tab right at the top. If you have an inexpensive test light or volt meter, you can often probe that metal tab to see if the fuse is blown without having to remove it from the fuse panel. BTW, if you find it difficult to remove a fuse, there’s a tool available at auto parts stores you can buy to make it easier.

Not everything in the car has an electricity component to it. The thermostat for example has no electrical connection, so the engine under-heating, that’s not likely a fuse related problem. Only if the engine cooling fans wouldn’t turn off would engine under-heating be electrical related usually.

Since fuses usually either work or don’t, the intermittent cranks but doesn’t start and run is not likely a fuse problem. That’s more likely a ignition system or fuel problem, usually due to deferred maintenance.

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The average age of cars on the road is about 11.5 years. Average! That means there are a LOT of “old” cars on the road being repaired every day.