Please help if you can No Power to Fuse LCD
08-21-2010, 08:33 PM
#1
Heel & Toe
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Please help if you can No Power to Fuse LCD
1985 C4 Corvette
I ordered a Shop Manual but it has not arrived. I would like to drive my new ride but can't due to no power to the LCD fuse.
I have been trying to track down why I am not getting any readings from the fuse using my meter. Does anyone know what would cause the fuse plug not to have power. It did have a blown fuse in it. Any help would be great.
My horn does not work, no dash.
I did a test and set the alarm and when I unlocked the door and opened it through the opened window the horn started beeping. I didn't know how to shut it off so I undid the battery.
One more thing the car belonged to the father of the seller, who passed away and the car sat for 5 years. She could not find the keys so she had the ignition replaced. The key does not have a chip (should it) Ted
I ordered a Shop Manual but it has not arrived. I would like to drive my new ride but can't due to no power to the LCD fuse.
I have been trying to track down why I am not getting any readings from the fuse using my meter. Does anyone know what would cause the fuse plug not to have power. It did have a blown fuse in it. Any help would be great.
My horn does not work, no dash.
I did a test and set the alarm and when I unlocked the door and opened it through the opened window the horn started beeping. I didn't know how to shut it off so I undid the battery.
One more thing the car belonged to the father of the seller, who passed away and the car sat for 5 years. She could not find the keys so she had the ignition replaced. The key does not have a chip (should it) Ted
Last edited by yesitsfat\st; 08-21-2010 at 08:49 PM.
08-21-2010, 09:41 PM
#2
Le Mans Master
No vats in an '85. Check your other thread for another thing to try. In the meantime I will see if I can find anything in my fsm but I have to warn you, reading an electrical schematic is NOT the best thing I do.
08-21-2010, 10:18 PM
#3
Le Mans Master
I checked my fsm I have on cd but there are no schematics on it. If you can check for loose wires and blown fusible links I will get into my fsm in the garage and get back to you tomorrow. Maybe someone else can chime in sooner.
08-22-2010, 01:10 PM
#4
Burning Brakes
Allright, here goes nothing..
There are three circuits that supply power to the Instrument cluster. Three fuses: The LCD fuse, the CLSTR fuse and the TAIL fuse (thru the light switch, which in turn also feeds the INST fuse, which then feeds the cluster backlights).
The TAIL fuse is supposed to be hot at all times, the CLSTR fuse is supposed to be hot with the ign switch in Run, and the LCD fuse is supposed to be hot at all times.
Now. The LCD fuse gets It's always hot power from fusible link A (red). Other fuses are also fed by that fusible link: the HORN in-line fuse (and therefore the theft deterrent system), the PWR ACCY fuse, HAZ fuse, and RR HATCH fuse. In addition the Ign switch and the A/C system are all fed from fusible link A.
If all or any of That stuff has power then the fusible link must be good. There is a junction in the wire harness where all of these various wires tie together - S203. S203 is located in the wire harness along the firewall on the interior side above the steering column. Not easy to reach.
There are two large red wires that run from S203 to the fuse box - one of them feeds both the LCD and HATCH fuses (the other feeds the PWY ACCY and HAZ fuses). Does the power hatch release work? That circuit is fed by the Same supply wire coming into the fuse box as the LCD fuse..
Perhaps someone has spliced into one of those red wires in the past and now it's broken? Perhaps the fuse box itself has a problem? Don't know. If all else fails I would dig into the dash and get to the back side of the fuse box for a look there. If necessary then run a new hot wire to feed whichever of the red wires is dead.
Oh - the alarm system. You Arm it, and also Disarm it, by using the door key to lock/unlock either door. Only that method - the key in the Ignition switch will NOT do anything for the alarm. This assumes that the switch(s) at the door lock tumbler(s) is still working, of course. Not necessarily a good bet.. Note that you can "kill" the alarm system by removing the in-line fuse for the horn (behind the Operator Information Center panel in the center of the dash, along with the alarm and horn relays, also the flashers..). This does also remove power for the horns as well though.
And, like Midnight85 said, there is no resistor on the key in '85, just a plain, simple, old fashioned, normal key.
And a comment. It sounds like you Really need the circuit diagrams in the manual. The Helm manual (the factory book). I hope that's what you have on order..
There are three circuits that supply power to the Instrument cluster. Three fuses: The LCD fuse, the CLSTR fuse and the TAIL fuse (thru the light switch, which in turn also feeds the INST fuse, which then feeds the cluster backlights).
The TAIL fuse is supposed to be hot at all times, the CLSTR fuse is supposed to be hot with the ign switch in Run, and the LCD fuse is supposed to be hot at all times.
Now. The LCD fuse gets It's always hot power from fusible link A (red). Other fuses are also fed by that fusible link: the HORN in-line fuse (and therefore the theft deterrent system), the PWR ACCY fuse, HAZ fuse, and RR HATCH fuse. In addition the Ign switch and the A/C system are all fed from fusible link A.
If all or any of That stuff has power then the fusible link must be good. There is a junction in the wire harness where all of these various wires tie together - S203. S203 is located in the wire harness along the firewall on the interior side above the steering column. Not easy to reach.
There are two large red wires that run from S203 to the fuse box - one of them feeds both the LCD and HATCH fuses (the other feeds the PWY ACCY and HAZ fuses). Does the power hatch release work? That circuit is fed by the Same supply wire coming into the fuse box as the LCD fuse..
Perhaps someone has spliced into one of those red wires in the past and now it's broken? Perhaps the fuse box itself has a problem? Don't know. If all else fails I would dig into the dash and get to the back side of the fuse box for a look there. If necessary then run a new hot wire to feed whichever of the red wires is dead.
Oh - the alarm system. You Arm it, and also Disarm it, by using the door key to lock/unlock either door. Only that method - the key in the Ignition switch will NOT do anything for the alarm. This assumes that the switch(s) at the door lock tumbler(s) is still working, of course. Not necessarily a good bet.. Note that you can "kill" the alarm system by removing the in-line fuse for the horn (behind the Operator Information Center panel in the center of the dash, along with the alarm and horn relays, also the flashers..). This does also remove power for the horns as well though.
And, like Midnight85 said, there is no resistor on the key in '85, just a plain, simple, old fashioned, normal key.
And a comment. It sounds like you Really need the circuit diagrams in the manual. The Helm manual (the factory book). I hope that's what you have on order..
08-22-2010, 10:09 PM
#5
Heel & Toe
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Thanks everyone, I removed everything and found my problem. I found a mouse nest in behind the radio. One wire chewed and after cleaning out the mess, I fixed the wire now I have a horn, fog or driving lights, my hatch works and I an see my dash. Now I have another problem everything on the dash is 000's from the speedo, tech, fuel, temp. Everything any ideas??
I ordered the GM service manual with electrical extra. It's a red book!
I ordered the GM service manual with electrical extra. It's a red book!
08-22-2010, 10:56 PM
#6
Le Mans Master
Sounds like the mouse dined on more than one wire, look over in the area where the wiring plugs into the digidash. Once you get everything fixed get yourself some Bounce dryer sheets and place them all over the interior and change them out about every 3-6 months. The dryer sheets will keep the little bastards away.
