electrical troubleshooting 101


Post Whore
Oct 9, 2009
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Evansville Indiana
As part of the suggestions from our members I am going to be making a troubleshooting sticky to help people out. I will try to do some general troubleshooting as well as possibly a few common electrical pieces that are known to go bad on our cars. Some of the troubleshooting procedures will sound extremely basic and some will even sound stupid honestly but its important to follow all the instructions when chasing electrical gremlins.

The first thing we need too do when troubleshooting electrical problems is to isolate the problem so we can see what is causing it. This sounds basic and simple but can be a little tricky sometimes and is almost always the first step. For example if your speaker stops playing it could be the speaker is blown, or it could also mean that your amp is blown, or it could also mean your deck is bad or that there is just a bad cable between one of these pieces preventing the signal from reaching the speaker.

So lets start with just that example, your speaker stops playing. To isolate the problem we will do a couple of simple things first to find its source. First off start simple -
1.) Is the deck on? If so is there a chance you have the balance/fader adjusted so that speaker has no signal? These are all possibilities and if we don't start there, we will end there much much later....

If everything on the decks balance/fader looks ok the check the amp.

2.) Is the power light lit on the amp? For this example we will say it is so there is no reason to check its fuse or power wiring, simply make sure all the cables/wires are connected and there is NO wire showing/hanging out. While you are there give a light pull/tug/wiggle on the wiring going to it as it should be able to take this and it should cause no problem. If the wiring doesn't change anything then to test for a bad connection inside the amp try using your finger to tap on the top and see if it helps. I know it sounds funny but they are called technical taps and you will be amazed how many times you can use it to diagnose a problem and light tapping on it should not cause a problem.

3.) Finally do a quick check on the speaker just to be sure all the wiring is connected. This is easy to do if its mounted in the rear deck, but not so easy if its a door speaker for example. If you can get to the back easily then grap the wires and wiggle them around a little like you did on the amp.

4.) Ok so now we will start at the speaker and work our way back too the source too see if we can find the problem. If you are running 2 speakers off of your amp its really easy just too swap the speaker wires at the amp and see what happens. If the bad speaker switches sides then we know its the amp or before, if the same speaker still does not work then we know its the wire to the speaker, or the speaker itself. If the same speaker still does not play then take an ohm meter and test too see what ohm value it is listed at.

5.) Testing the next piece in the signal, the amp, is really easy to do. All we need to do there is to swap the rca signal feeding it. Again if the same speaker has no sound, then its the amp is bad. If the other speaker stops working Then we know the its before our amp. You can double check that its the amp that is bad by taking your mp3 player with some headphone-rca cables and plug that into the amp as your new source. If the same speaker still doesn't play, your amp is bad

6.) To test the RCA cables you can do two things. You can either swap the rca cables on the back of the deck, or take your mp3 player and plug it in to the cables behind the deck. If the same speaker still does not play, you know its the cables. You can confirm this by getting a cheap set and running them above the carpet straight too the amp, if when they are plugged in the speaker plays you have confirmed its the cable. If the bad speaker switches though, then you can be sure its the deck since it is all that is left. Be sure all the cables are connected correctly back there and if so, try a different deck

This is just the first installment or chapter 1. Chapter 2 will be testing the TPS if there are any other suggestions for parts too test please let me know.

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