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I have a short.. Can you help me figure it out...

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Old Apr 24, 2006 | 06:23 PM
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I have a short.. Can you help me figure it out...

Ok so i got some gauges and i wired all the lights right off the light from the cigarette light surround. So there were like three power and ground wires coming off the light for cigarette lighter. Everything was fine until i took my dash apart a bunch of times. Now im pretty sure one of the wires shorted out or something. Becouse now my gauges dont light up along with the origanal light. As well as my cluster back lights. I checked every fuse and they are all fine. When i switch on my lights everything it fine other than the interior lights. My clock dims down so i figure it is sending the right signals or whatever.
Thanx for any input on where to start diagnosing this. I have since cut the all the wires for the gauges and ran the wires back to stock but still nothing.
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Old Apr 24, 2006 | 07:22 PM
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could a short burn out the dimmer **** on the headlight switch? It looks like every light that can be dimmed out is not turning on. On second though the cig. lighter light doesn't dim so maybe it isn't the problem. Ice any ideas?
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Old Apr 24, 2006 | 10:09 PM
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ok im pretty sure what happened was that the pos. and neg. shorted together on the cig. lighter light. The one that also lights up the ash tray/ coin packet at night. If these wires are left shorted could it have burned out the dimmer control on my headlight switch. Thus taking out all the lights that get dimmed. I noticed my logicon doesn't light up any more however my parking and headlights work normal along with my clock going into "night mode" when the lights are turned on. Is there any way to bypass the dimmer and just have the lights stay all the way bright? Icemark? any comments....
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Old Apr 24, 2006 | 11:21 PM
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may have burnt out a Fuse ..down under the dash,driver's side Kick panel..in the corner..check the Room fuse and the Illimination fuse..
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Old Apr 25, 2006 | 01:55 AM
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pull one of the lightbulbs out and check the + side for continuity to ground.
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Old Apr 25, 2006 | 01:56 AM
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yup misterstyx69 is right, sounds like a room or illum fuse, done it before...
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Old Apr 25, 2006 | 02:33 AM
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Overloading the circuit. ah screw it just throw a bigger fuse in(thats a joke), if you blew your fuse and it keeps blowing you probably have a short to ground before the gauges. Did you do it properly and solder the connections. If the fuse didnt blow you might have a openn circuit. The connection probably isnt making it to a ground make sure all the grounds are good, dont ground to a painted part of the frame, file off the paint and ground to that area.
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Old Apr 25, 2006 | 02:41 AM
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No a short should not burn out the switch. It should blow the fuse first, hopefully...If the positive and negative on the cigarette lighter shorted together you would blow a fuse or ruin the entire circuit. If the dimmer doesnt work i would recheck the fuses maybe you missed it. Like i said early if the fuse keeps blowing there is a problem with the circuit dont keep feeding it fuses. And dont use a larger fuse that was a joke and if used could fry your circuit(not good!)
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Old Apr 25, 2006 | 08:16 AM
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do the parking lights work or are they dead with the dash lights???

If the parking lights are also out, then you probably have a blown fuse... if the parking lights do work, then you probably have a burnt up light switch
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Old Apr 25, 2006 | 09:33 AM
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the parking lights work fine... No fuses are blown. Theye wehere all checked with a multimeter for continuity. Is there any way to check the headlight switch to see if that is truely the problem? Also is there anyway to feed 12v an a ground into the headlight harness and get the dash to light up? I did this once for my blinkers but im not sure if it can be done with the dash lights. Also can you bypass the dimmer part of the headlight switch and have them light up all the time. I had my connections solder but for some stupid reason i taped them instead of skrink wrap. The tape moved and the pos. and neg. when touching when i pulled the dash apart.
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Old Apr 25, 2006 | 09:45 AM
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you might want to check the light switch for continuity and the resistances. also this is kinda gheto, but smell the switch. if it smells like burnt electricity it's probably toasted... you can make yourself a new switch using more robust components from Jameco or digikey. all you really need is a new potentiometer with the same resistance but can handle a higher amp draw... you should be able to get one the same physical size as the original btu ICEMARK will and should correct me if i am wrong.

hope that helps at least a little,
Ryosuke

P.S. how many aftermarket gauges are we talking about here anyway? and were you just running the lighting for them off the lighter?
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Old Apr 25, 2006 | 10:01 AM
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From: NJ
2 gauges and ya it was just the lighting. I was looking in the fsm and cant seem to figure out how to test the dimmer **** on the switch. Any help with how to do that would be great.
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Old Apr 25, 2006 | 10:22 AM
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From: Rohnert Park CA
Originally Posted by driftin8ez
the parking lights work fine... No fuses are blown. Theye wehere all checked with a multimeter for continuity. Is there any way to check the headlight switch to see if that is truely the problem? Also is there anyway to feed 12v an a ground into the headlight harness and get the dash to light up? I did this once for my blinkers but im not sure if it can be done with the dash lights. Also can you bypass the dimmer part of the headlight switch and have them light up all the time. I had my connections solder but for some stupid reason i taped them instead of skrink wrap. The tape moved and the pos. and neg. when touching when i pulled the dash apart.
Well internally the reostat in the switch controls a large FET for the dash lights, but the simplest way to get the dash lights to light, is just to simply jump the dash lights wire to the parking lights wire.

You just wouldn't get the dimmer capability doing that
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Old Apr 25, 2006 | 10:22 AM
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look at page 15-14 of the Body Elecetrical System section in the FSM http://www.teamfc3s.org/main/factory...CAL_SYSTEM.pdf

near the top written upside down it says "Dimmer &..." I would start there... I wish that scan came out cleaner though.

maybe also check a Haynes manual??

hope that helps,
Ryosuke

EDIT: IceMark - you wouldn't get the dimmer capability unless you wire in your own rheostat / potentiometer... would it be a good idea to jump the switch IF you wanted to draw more power from the circuit?

Last edited by takahashiRyosukeFC3S; Apr 25, 2006 at 10:25 AM.
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Old Apr 25, 2006 | 10:35 AM
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From: Rohnert Park CA
Originally Posted by takahashiRyosukeFC3S
IceMark - you wouldn't get the dimmer capability unless you wire in your own rheostat / potentiometer... would it be a good idea to jump the switch IF you wanted to draw more power from the circuit?
Yes, you wouldn't get a dimmer feature unless you wired your own reostat.

The factory switch is kinda cool, it uses the reostat to control the FETs output, but the FETs main power in comes from the parking light switch in the circuit.

So, by jumpering past the FET/switch, you just re-connect up something that is already tired into the parking light circuit. It makes it a very stable circuit, and not subject to the usual heat fade from resistance increase that happens when you run power through a higher power reostat.

Plus you don't end up with the reostat burn out that used to happen a lot on cars back in the 60's and 70's.

If driftin8ez opens up the switch, chances are (if it is a S4) you'll be able to see the trace that got burnt pretty easy. A burnt trace does not always mean a wasted FET.
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Old Apr 25, 2006 | 10:50 AM
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Originally Posted by driftin8ez
I had my connections solder but for some stupid reason i taped them instead of skrink wrap. The tape moved and the pos. and neg. when touching when i pulled the dash apart.
If the positive and negative were touching and you didnt blow a fuse then something else in the circuit worked as a fuse and blew.Just hope the wires are still good.If you have a DMM(digital multi meter) just check the dimmer for continuity. The haynes manuel does have wiring diagram(might be the only thing its good for), so i would find the dimmer circuit and start from the source voltage and then start testing to find where the voltage drops off.
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Old Apr 25, 2006 | 01:25 PM
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ok im going to jump the wires and bypass the reastat untill i get a new switch. Any idea what color wire is for the dash light power and what color is the power for the parking lights. I assume i can do this all at the harness that plugs into the headlight switch.
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Old Apr 25, 2006 | 02:46 PM
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i have a series 5
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Old Apr 25, 2006 | 03:26 PM
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ok i figured it out sort of.... The red w/ grenn strip wire needs to see 12v when i turn on my lights to lite up the dash and the others lights that are out. I did that and all the lights came on. So i guess i blew the reostat in my headlight switch. I just need to know what color wire in that same harness get power when you turn on the parking lights. Then i splice them together as a temp fix and i have dash lights at full bright. anyone know the color of the wire i need to splice.
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Old Apr 25, 2006 | 03:35 PM
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ok i got it. I just jumpered the wires so when i get a new switch it will be back to normal.
Thanx for the help guys.....
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Old Apr 25, 2006 | 04:58 PM
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I do have rebuilt headlight switches available on my website if that turns out to be the problem
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Old Apr 25, 2006 | 07:19 PM
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Thanx ice nice plug... The switch is the problem. I guess the reostat burnt out from the short. I usually have my guages on full blast anyway so it isn't that big of a problem. Maybe someday it will bug me but im usually driving in bright areas at night so i need the gauges all the way up to see them. Well again thanx for the help guys....
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Old Apr 25, 2006 | 07:21 PM
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Originally Posted by Icemark
I do have rebuilt headlight switches available on my website if that turns out to be the problem
I love it when you do that.
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