Electrical Problem, Instrument Panel totally out, 89/AT
04-04-2008, 05:25 PM
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Electrical Problem, Instrument Panel totally out, 89/AT
Hello All, I recently purchased an 89/AT that has a electrical Problem, the last owner told me the aftermarket stereo has a short, and blows the 15AMP fuse, My Instrument panel is out, nothing works, Speedo, Tach, Temp gauge, Gas gauge, are shut, i pulled the stereo out, test the wires, the stereo Hot wire (RED) is shorting with Ground Wire (Brown), all the interior lights are also out, my question is how i can trace the wires, and is this has anything to do with instrument panel. Thank you.
04-08-2008, 12:15 AM
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It might help to advise what does work. Does the car run? Or if not, does the starter turn over? Do the lights and turn signals work? Give these guys a place to start and you'll get some help. Does the car have a Clifford or after market alarm system? Has the battery discharged?
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04-08-2008, 12:28 AM
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04-08-2008, 01:32 AM
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The stereo doesn't have a fuse... so which one blows?
Step one - remove the stereo completely from the console - what is it connected to ? wire colors and other connection on those wires that yu can see..?
Just presume for now that the stereo installer butchered something - its almost always true...
Alan
Step one - remove the stereo completely from the console - what is it connected to ? wire colors and other connection on those wires that yu can see..?
Just presume for now that the stereo installer butchered something - its almost always true...
Alan
04-08-2008, 01:57 AM
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Also, check fuse 24. That's the interior light fuse. If it blows the instruments don't work, even though the instrument panel has its own fuse (10).
If the interior light fuse keeps popping, check the overhead light - it has a habit of shorting against the body.
Of course, pull the radio like Alan said, and check fuse 24 too.
If the interior light fuse keeps popping, check the overhead light - it has a habit of shorting against the body.
Of course, pull the radio like Alan said, and check fuse 24 too.
04-08-2008, 08:18 PM
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Car Runs fine, everything work, lights, turn signals, horn, Stereo is completely out, it blows RADIO/AMP Fuse, instrument panel is completely out including interior lights, Odometer, Tachometer, Fuel gage, Temp gauge are not working, only Battery charge gauge and oil pressure gauge is working, when i turn the car On the instrument panel light is on, when i turn the headlight on, instrument panel lights goes out, I'm in Florida
It might help to advise what does work. Does the car run? Or if not, does the starter turn over? Do the lights and turn signals work? Give these guys a place to start and you'll get some help. Does the car have a Clifford or after market alarm system? Has the battery discharged?
Welcome to Rennlist. Where are you located?
Welcome to Rennlist. Where are you located?
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04-08-2008, 08:38 PM
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Like Allen say's, the radio is probably playing havoc with your electrical system. I think you need to completely disconnect it and if an amp has been added, disconnect that also.
I have had the rear dome light short out, like Bill mentions, and there are a lot of circuits on that Fuse #24.
The fact that the instrument panal lights go out when the headlights go on is a good puzzle for Allen to chew on. Are you sure they don't just dim?
You could be dealing with two different problems here. When you start the car, try turning the key back toward off about halfway, and see if the guages and panal lights come on, indicating a bad switch.
I'm just guessing at stuff here.
I have had the rear dome light short out, like Bill mentions, and there are a lot of circuits on that Fuse #24.
The fact that the instrument panal lights go out when the headlights go on is a good puzzle for Allen to chew on. Are you sure they don't just dim?
You could be dealing with two different problems here. When you start the car, try turning the key back toward off about halfway, and see if the guages and panal lights come on, indicating a bad switch.
I'm just guessing at stuff here.
04-08-2008, 08:43 PM
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04-08-2008, 10:02 PM
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If i left anything out, Car is an 89/AT US model, Stereo is out of the car, it is an aftermarket radio, i purchased the car and the po told me radio has a short, here is the problem, Instrument panel is out, Speedometer, Tachometer, Fuel gauge, Temp Gauge, Gas Gauge, Are not working, Fuse #22 (Radio-Amplifier) blows as soon as i replace it, Car runs fine and i drive every day. all exterior lights are working, Interior light out, the original amp on the driver side next to the seat is missing, the radio connection wire was cut and the power was applied to the aftermarket radio, The radio plug has 3 wires, 2 RED and 1 Brown, i checked with ohm meter one of the red wires is shorting with the ground wire. PO told me since radio has short and fuse is blown that's why the instrument panel is out, does this short has anything to do with the instrument panel?
04-09-2008, 01:09 PM
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The measurement you did with an ohmmeter across a battery supply is not meaningful. You need to validate if there is indeed a short - what voltage is on the red wire w.r.t. the ground?
I'm telling you there is no radio fuse (except perhaps on the back of the radio itself)
(BTW - there is no radio fuse on ANY 928 - except on the radio itself - a good reason for being very careful in head unit wiring and STUPID STUPID idea by Porsche)
The "booster" fuse only controls the amplifier for audio - under the cover next to the passenger seat - look for a cut red wire there and see if its shorting to ground (chassis). It probably has no bearing - but on some years there are other things attached to that fuse too (unadvertized usually).
The reason you get dash lights without your external lights on is because they are controlled differently.
With lights off the dash always lights to a bright fixed level (for tunnels etc). With the lights on this switches over to the variable illumination controlled by the rheostat. Seems like your dash lighting fuse (#44 for an '89) is out or the rheostat has a problem (bypass it with a jumper).
The guages being non-operational is likely due to fuse #24 which supplies the interior lights and digi-dash (unadvertized usually). Likely the interior lights have a short and this is what causes your primary issue.
Take out the 3 roof mounted interior lights - its likely one is broken and shorting to metal in the roof area - look for shorts on the red wire connections. There are other places it could be but start there - its the most common
Once you fix this - your non-operational rear hatch relaease should start working too.
Alan
I'm telling you there is no radio fuse (except perhaps on the back of the radio itself)
(BTW - there is no radio fuse on ANY 928 - except on the radio itself - a good reason for being very careful in head unit wiring and STUPID STUPID idea by Porsche)
The "booster" fuse only controls the amplifier for audio - under the cover next to the passenger seat - look for a cut red wire there and see if its shorting to ground (chassis). It probably has no bearing - but on some years there are other things attached to that fuse too (unadvertized usually).
The reason you get dash lights without your external lights on is because they are controlled differently.
With lights off the dash always lights to a bright fixed level (for tunnels etc). With the lights on this switches over to the variable illumination controlled by the rheostat. Seems like your dash lighting fuse (#44 for an '89) is out or the rheostat has a problem (bypass it with a jumper).
The guages being non-operational is likely due to fuse #24 which supplies the interior lights and digi-dash (unadvertized usually). Likely the interior lights have a short and this is what causes your primary issue.
Take out the 3 roof mounted interior lights - its likely one is broken and shorting to metal in the roof area - look for shorts on the red wire connections. There are other places it could be but start there - its the most common
Once you fix this - your non-operational rear hatch relaease should start working too.
Alan
04-09-2008, 04:03 PM
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04-09-2008, 05:35 PM
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The measurement you did with an ohmmeter across a battery supply is not meaningful. You need to validate if there is indeed a short - what voltage is on the red wire w.r.t. the ground?
I'm telling you there is no radio fuse (except perhaps on the back of the radio itself)
(BTW - there is no radio fuse on ANY 928 - except on the radio itself - a good reason for being very careful in head unit wiring and STUPID STUPID idea by Porsche)
The "booster" fuse only controls the amplifier for audio - under the cover next to the passenger seat - look for a cut red wire there and see if its shorting to ground (chassis). It probably has no bearing - but on some years there are other things attached to that fuse too (unadvertized usually).
The reason you get dash lights without your external lights on is because they are controlled differently.
With lights off the dash always lights to a bright fixed level (for tunnels etc). With the lights on this switches over to the variable illumination controlled by the rheostat. Seems like your dash lighting fuse (#44 for an '89) is out or the rheostat has a problem (bypass it with a jumper).
The guages being non-operational is likely due to fuse #24 which supplies the interior lights and digi-dash (unadvertized usually). Likely the interior lights have a short and this is what causes your primary issue.
Take out the 3 roof mounted interior lights - its likely one is broken and shorting to metal in the roof area - look for shorts on the red wire connections. There are other places it could be but start there - its the most common
Once you fix this - your non-operational rear hatch relaease should start working too.
Alan
I'm telling you there is no radio fuse (except perhaps on the back of the radio itself)
(BTW - there is no radio fuse on ANY 928 - except on the radio itself - a good reason for being very careful in head unit wiring and STUPID STUPID idea by Porsche)
The "booster" fuse only controls the amplifier for audio - under the cover next to the passenger seat - look for a cut red wire there and see if its shorting to ground (chassis). It probably has no bearing - but on some years there are other things attached to that fuse too (unadvertized usually).
The reason you get dash lights without your external lights on is because they are controlled differently.
With lights off the dash always lights to a bright fixed level (for tunnels etc). With the lights on this switches over to the variable illumination controlled by the rheostat. Seems like your dash lighting fuse (#44 for an '89) is out or the rheostat has a problem (bypass it with a jumper).
The guages being non-operational is likely due to fuse #24 which supplies the interior lights and digi-dash (unadvertized usually). Likely the interior lights have a short and this is what causes your primary issue.
Take out the 3 roof mounted interior lights - its likely one is broken and shorting to metal in the roof area - look for shorts on the red wire connections. There are other places it could be but start there - its the most common
Once you fix this - your non-operational rear hatch relaease should start working too.
Alan
Allen and everyone who replied, Thank you so much, I checked the Fuse #24, it was missing, tried to replace but it was shorting out, I removed all 3 interior light, the one in the back had a melted wire, replaced fuse #22 and #24 and everything is on, haven't driven the car yet, in the instrument panel where the mileage is shows Check Coolant, but coolant is fine, there is two more problems that i have to check, AC was completely repaired, the back blows a very cold Air, Front blows worm air, also there is a vacuum hose from the booster that its been disconnected and its plug by an screw.
here is the link to the pic.
http://family.webshots.com/photo/200...52020144LVZGqG
I will post after a test drive.
Thank You.
04-09-2008, 05:43 PM
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The vents flaps in the dash and the hot water valve ALL use Vacuum. No vacuum and the heater valve circulates hot water all the time and warms the cooled air.
04-09-2008, 05:57 PM
#15
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check the light above the mirror this one melts and shorts out the harness, the lights usually go bad from leaving them lit and the doors open or the hatch , I dont usually have my lights turned on with the door switch. just the manual .
Alan has a source for new light housings that are better and dont seem to melt
Alan has a source for new light housings that are better and dont seem to melt