Hi Everyone,

I've owned my 1999 4runner for a week. I love it. Having had tons of negative experiences with electrics in cars, I was a bit worried about the automated antenna. The previous owner seemed to have some trouble too, as I could see in the service records that parts of the automated antenna were replaced some time ago.

Well, my concerns have been proven to be true, this morning after starting the car the radio didn't work. I was first worried it just might be stuck somehow, but didn't take me long to figure it must be the fuse, since a couple of other things in the dashboard didn't work either.

I checked the fuse box under the hood, and grabbed the responsible fuse = blown.

Luckily there was a replacement fuse in the fuse box.

Now I noticed the following:

There originally were three 15A fuses, and only one was left.

This makes me thinking that the previous owner might have been replacing the radio fuses (or others) several times and it is a reoccurring problem.

Of course, this is just speculation.

The question I have:

Why do fuses just blow? I did not do anything in or to the car.

Any info appreciated.

Also, any way of switching off the function that the antenna goes up and down automatically, depending if radio is on or off?
I'd rather have it up all the time and not worry abut it going kaput.

Thank you techies.

 

Fuses generally blow when a wire for the item shorts out to ground, So there might be some wire behind the Head Unit thats broken and grounding out.

IIRC there is some way of adding a switch to the antennae, Or you can do the tacoma whip mod.

Good luck.

 

Think of a fuse as a safety feature. They interrupt the power supply in a circuit to protect it. When a circuit is compromised, for whatever reason, AND the circuit begins to draw more current than it is designed to handle, things heat up fast and electronic components can get fried. Cheap or expensive components in cheap or expensive cars. So to prevent fat repair bills and discourage electrical fires, a fuse is designed into a circuit. When things get ugly, the cheap fuse will blow, give its life, to protect an expensive component or to avert an electrical fire. Even if fuses cost $10 each, they would still be cheap.



So if you run out of a 15 amp fuse and use a 20 amp fuse to complete the circuit, it will work but at the opportunity cost of overriding the safety feature, up to a point. Some people in your same situation would risk that rather than to keep replacing fuses, that blow all the time. It's one thing to do it when you are 30 miles from the nearest paved road and another to do it just for the sake of convenience. I am glad that you are thinking about addressing the electrical problem but cutting the wire that powers the electrical antenna unit, either manually or by installing a remote switch, may only be treating the symptoms of the actual underlying issue if the actual issue is a worn wire grounding itself when and where it is not supposed to. On the other hand, it is possible that friction from the antenna unit is causing it to struggle under a load that overwhelms it. You can rule this out by simply wiping down the extended antenna with a penetrating lubricant such as triflow. This MAY keep the antenna motor from trying to draw more current under a load and maybe popping the fuse. A squirt of triflow might do it for you but there might be two or three additional reasons in conjunction with the antenna motor. If you disconnect the antenna unit and all goes well for a few days, it is likely that there are no other issues, yet. It's only a matter of time before something else comes along.

The first thing I would check is the fuses box itself. Make sure that the correct fuses are in the right place, don't assume. Get a diagram. Next, disconnect the power antenna for a few days. If, problem solved, then lube the antenna, and connect it for a few days. If, not, then your best bet is to get a copy of the wiring diagram, a cheap voltmeter and horse trade with someone on campus to systematically check each and every connection in that circuit. You would want to find an electrical engineer type if you can now that school is out. My brother is up their working in a laboratory all summer so I know that there are big brains floating around and if you are one of them, then I say go for it yourself. If you are not inclined to do so; horse trade.

 

Thank you for the long answer. I understand why fuses exist and why they blow in general, but not why they blow in a car that was built to last and should have all fuses right from the beginning, expect the previous owner out a wrong one in of course.

For now I am just going to use the radio as usual, as I need to get to know the car and its quirks. Maybe it will happen again, maybe not.

I do have a voltometer at home, and would love to figure it out myself if it happens again...

 

Exactly, between you and the factory someone else has placed their hands on your chariot. They may have been going through fuses like breath mints and one day the gasoline station only had a pack of X when he/she needed Y and he/she decided to go for it anyway. I was just suggesting that you start off with a simple, and free way to rule out the obvious, the right fuses in the right slot, before you get into the more time consuming and tiresome aspects of electrical trouble shooting.

One of my first job positions was a motorcycle mechanic apprentice at Yamaha Motorsports in Southern CA, back when Wayne Rainey was the poster boy for Kenny Robert Yamaha. Like most work environments, there is a hierarchy in mechanic shops. On one end of the spectrum are the shop rats and on the other are the specialists, the most valued of these was the electronics trouble shooter. People in general hate to trouble shoot electronics. A seasoned taxi mechanic can swap out an entire engine before someone else figures out why your radio fuse blows. Once, it took me five minutes to isolate a faulty kickstand switch on an fz600 that would not start after a senior mechanic had spent, some time on it. I went from oil and tire changer to after market performance parts installer overnight but I also got all the electronic work orders after that. win/lose. The mere fact that you are ready and willing to trouble shoot your own rig says a lot about you. Good luck with that.

As far as cars being designed to be this or that, well the Italian cars are notorious for electronic issues and the German cars are no better, some 7 series BMWs are so jam packed with electronic doo dads that it is only a matter of time before something goes south. I had a boss that had a 2005 Maybach in the shop for electronic issues more than any other car he has ever owned. Which is just my way of saying that dropping more scratch for a sweeter ride is not going to keep electronic issues from crashing your party. Electronics is the great equalizer in the automotive industry.

 

Thanks jackwolf. The next time it blows I'm gonna buy a good fuse first and check all the other ones of course. I should probably check the other ones anyway!

I am from Germany, and for about 10 years or so, we have a new job apprenticeship that takes 3,5 years to study and complete.

It's a mix between car mechanic + electrician + computer scientist. If you'd translate the word it would be sth. like mechatrician ;-)

They are in high demand, I am not surprised!

 

Well use a schematic diagram to make sure that a 15 amp fuse, and not a 20amp fuse, is in the 15 amp fuse slot and yes, do this for all of the slots. Harbor Freight makes a good fuse checker. It has an LED bulb that lights up but you can also use the voltmeter probes on each slot to take readings.

Back in my school "daze" I almost went to work at an automotive factory in Stuttgart, Germany as part of a six month exchange student program sponsored by a technology-transfer/German culture awareness campaign. I wanted to only spend three months of the summer on it in between semesters at Franklin College in Switzerland but I got picked up by a petroleum company sponsor and attended the SVIM Program at the Harvard Business School instead. Besides the unemployment rate in Deutschland was high and there was controversy over the programs billets taking jobs away from Germans. I did not want to be there under those circumstances. I never did go to Switzerland either. I wish I had.

I really like the European model of focusing on vocational skills training. In America we tend to focus on obtaining degrees in fields we are not going to be working in, there are of course a handful of exceptions. My mechanic on the east coast is a product of European vocational training. He is Mercedes Benz trained and can work on anything. So when I heard that Audi was sending some German engineers to Lamborghini back in 98 I was not at all skeptical. I would love to get an Audi diesel into my light and nimble 2runner. Audi powered diesels are... well, I think the R10 speaks for itself.

 

good postings jackwolf and nice to run across someone who knows what of he speaks.

annanina-leaving the power antenna up all the time really only becomes an issue when you use motorized car washes.

Several folks have added a switch to control the up/down separately from the radio head unit. Even with the power antenna down you may still get acceptable reception.

 

Thank you sir.
Universities used to be forums, but rather than gather near the pillars in the piazza or plaza we can now just have a tab on a browser to teach and learn as well as to enjoy a little frolic and banter.

 

Hello again,

The fuse blew again this weekend. It is not official that this is a reoccurring problem.
Again, I do not remember having done anything to or with the car.

Also not working are the door lights, and the alarm that goes when I am not buckled up.

I assume all those things are related to the blown fuse.

@jackwolf:

I agree with you on the advantage of the vocational training. It's such a great model, and if you are going to a bakery in Germany for buy bread, the person behind the counter usually did a 3 year apprenticeship in how to sell baked goods and all aspects of a bakery before they are allowed behind the counter :-)

Now to the fuse problem. You recommended using a fuse checker. I have that fuse diagram in the manual of my car, why would I need a fuse checker?

I thought I'm just going to compare the fuse numbers to see if they match the diagram.

I guess it would be either or, correct?

If all fuses are correct, what is my next step?

I really appreciate your answers here. Thank you.

Hope there is an affordable solution to this problem, solvable by a layman, uhm laywomen.

****UPDATE****

Just checked the fuse box under the hood, and found a couple of fuses in slots that should be empty according to my chart. The fuses that weren't supposed to be there were not even plugged in, they just kind of loosely "resting" in some slots.

Then there was one 15A fuse that wasn't supposed to be were it was, so I took it out and replaced my blown DOME fuse with this intact one. Of course, all the lights etc work again, but I don't dare to use the radio!

Could that have corrected the problem?

So I understand, it is possible that fuse A in the wrong spot causes fuse B to blow? I thought all those circuits act independently from one another.

 

Whew you have a few issues electrically here. I am a bit thrown off by the "not sure this is reoccurring" it has happened again hence is it not re-occurring ? Not trying to nit pick just making sure we are understanding what you are explaining.

You want to be sure that the correct fuse amperage is in each slot as per the diagram. Never ever diverge from that. Catastrophic things can happen (good flame photo jackwolf)

I can't think of any simpler way to say it than that.

I think jackwolf is recommending a fuse tester because at times you can't tell if a fuse is actually "blown". It will look okay but not be functional. I realize that seems to defy logic-but it is true some times with these modern blade type push in fuses.

So first off -get yourself a massive supply of every possible fuse you will ever need.

Look at the diagram and write down the varied numbers 10a, 15a you know what I mean.

Then get to know your favorite auto parts store or my fave Harbor Freight. Again the key is to have a massive supply. at best possible price.

So then you always have a good one on hand, if the radio blow a fuse-you pop in another correct one, and thinking logically here- if it happens again in a day a week or a month you have a pretty good clue which circuit is "grounding out". If it takes a whole month to do so that in itself is sort of a clue...

I think you already know the answer-it sounds to this guy that sits behind a desk all day- like it could be related to your power antenna or the radio head unit or something else on that circuit. Maybe a cig lighter they are notorious for grounding out coming unclipped and so on-we have several....

Eventually you will tire of having to swap in a new fuse all the time. You'll get excited about pulling the radio bezel off and we'll take it from there if you get to that point.

I'll not joke about the Exploder- I am actually banned on another venue similar to this for a smart aleck comment about a Heep.

Lastly-this is Newbie Tech. Probably one of the least viewed areas of this fine forum. I urge you to expand the opinions offered over in General Electrical or even just the 3rd gen Tech section.

We're all nice here, and don't get many females posting-you deserve to get the widest variety of opinions and so on.