some sort of short

[SoobGoob]

i have a short in my 94 legacy. blows left low beam headlight, horn does not work, and the rear passenger side speaker works 50% of the time. from what GD has told me the cd player in it is from a pre-facelift with different wiring? if he reads this he might be able to shed some more light. but what im curious about is could it be the cd player thats causing this? or maybe a loose wire going to the speaker? any 2cents would be helpful thanks!

[EVOthis]

I would think it is possible....maybe not likely but electricity does some weird stuff........

[aircraft engineer]

I take it that the FUSE blows in the headlamp circuit? (There is no way the bulb could blow from a short)

 

Have fun - circuit tracing always means that the bad part is located right where you can't get to it without standing on your head and using your left hand only while twisting some solid cable with your right hand (and CURSING!!)

 

Really, though - check and see where the wire bundles go past metal "edges" and look for rubbing. IF you find an open bit of insulation, wrap it with a few layers of tape and see what happens (you could have more than one short even in the same cable)

[OB99W]

I take it that the FUSE blows in the headlamp circuit? (There is no way the bulb could blow from a short)[...]

Indeed.

 

 

Besides shorts or opens in wiring causing the headlamp not to light, it's possible that the socket isn't making good contact. Another possibility is that the assembly is physically loose -- vibration can cause shortened lamp life.

 

It's unlikely that the three electrical problems are directly related, at least in a factory-wired arrangement. Of course, if someone sufficiently clueless wired things, all bets are off.

 

For anyone not up on basic electrical circuits (and willing to admit that to at least themselves ), this link is a good starting point:

http://www.autoshop101.com/trainmodules/elec_circuits/circ106.html

[SoobGoob]

thanks everyone ill take a look today. i can admit wiring is not my strong point

[SoobGoob]

i mean the bulb went out before and i replaced it and not the fuse and it worked fine.... so what do you mean by the fuse is causing it to go out?

[porcupine73]

blows left low beam headlight, horn does not work, and the rear passenger side speaker works 50% of the time

None of those are necessarily related. If the lamp blew out once and you replaced and it has been ok. The speaker could be a poor connection or faulty speaker; sometimes when poeple put in different radios they don't solder the connections so they can work loose with time. Horn could be a poor ground or connection again,etc.

[SoobGoob]

this is the second time its blew

[porcupine73]

How long did it last between blowings? They're not the sylvania silverstars are they?

[SoobGoob]

the ones in it were silverstars the passenger side silverstar is still doing fine.

[porcupine73]

I was running sylvania silverstars for a while and then was changing them a couple times a year so quit using them; they just don't seem to last as long as regular bulbs.

[SoobGoob]

well im not sure how long the silver stars have been in GD would know since he put them in. but first the silverstar blew then the regular bulb blew...

[aircraft engineer]

Take a look at the headlamp connector plug. The one I was working on last had a problem with the PLASTIC PLUG HAD MELTED (poor contact). I don't know but is that the one with the !_! shaped bare contacts or the one with the plastic surround - sort of looks like a D with the 3 contacts inside?

 

Take a look at your bulb as well - is the filament inside the bulb intact or broken. IF broken, the bulb is burnt out.

 

Did you remember to wipe down the bulb outside with either rubbing alcohol or everclear and not handle the bulb with bare fingers on installation.

 

Those bulbs get so hot, the quartz glass will fail and take the filaments with it.

[SoobGoob]

the fililemt was broken. i replaces with a oem bulb. lets see how this works. still could not figure out the horn.... checked the wiring behind the cd/tape/radio and it all seemed to be in order

[aircraft engineer]

horn probs are usually with either the RELAY or the horn supply wire connection (maybe even the horn itself, but that's easy to check by just putting power directly to the horn input terminal. )

 

IF you have a friend and a multimeter, unplug the horn from the wire and check the voltage when someone pushes the horn button. Voltage but no sound - usually a bad ground at the horn

 

Listen for the click of the relay, too. If the relay clicks but the horn doesn't sound, then try the horn itself with the direct power (unless you did that first)

 

No voltage, then it's back upstream of the horn - test the relay if you can (or just put in a spare and see if it works).

 

Still no joy -

 

Next try to see which wire is the line to the horn button. Disconnect the battery and do a resistance test with the horn button held down and see if there's continuity. (or leave the battery hooked up and use a continuity light to check the circuit from the battery to the wire that connects to the horn button. Open circuit and you might have an "open" at the horn button.

 

The horn circuit is about as simple a relay circuit as there is. Sequential circuit trace backwards until you find the open (I would tend to suspect either the relay or a bad ground - RARELY a bad horn)

 

the button GROUNDS the output coil of the horn relay

 

the relay switches to provide power to the horn when the input circuit grounds (VERY low amperage circuit)

 

the horn sounds because power is supplied to the horn input terminal (moderate amperage circuit)