Digital Dash Went Out
Thread Starter
Track Day
Joined: Jul 2024
Posts: 24
Likes: 3
From: Northern NV
Digital Dash Went Out
I replaced power steering hoses and now the digital dash, tach, and speedometer no longer work on my 89 S4. I checked all fuses and they are fine. Interior lights are working. I have had problems with fuse 24 in the past prior to replacing interior lights. The battery went dead during the project and I charged it up to 100%. Engine starts fine. It did have some pressure on the alternator wiring at various times, but most of the time it was hanging from a support while unbolted. I also had to unbolt the driver side coil and move it around to get to the lines. I checked connections and they are secure. Also, there is a light on top right showing a car body and 4 wheels. I don't know what that is telling me. I saw a post from years ago that some guy had the same issue from a shop doing power steering lines, but no resolution was posted. Pod connections are secure. I had that off when fixing a vent control early this year. It was working fine prior to doing this project so what could I have pulled loose? Is the digital dash turned on by some wire at the alternator? To remove it, I have to drain the radiator again or I would check myself.
Team Owner
Joined: May 2004
Posts: 31,228
Likes: 4,215
From: Philly PA
John I would suggest you look at the all the fuses,
use the multi meter set to continuity,
then touch the leads to backs of the fuses,
you should hear a beep if the fuse is good.
NOTE the green lamp should go out after you drive the car,
part of Its signal comes from the ABS sensors.
For Stratford Shark
NOTE if your hatch release is not working,
first thing to do is push in the door pin switch and let it snap out, this should establish the ground,
THEN the hatch pull will operate if it has a good fuse
use the multi meter set to continuity,
then touch the leads to backs of the fuses,
you should hear a beep if the fuse is good.
NOTE the green lamp should go out after you drive the car,
part of Its signal comes from the ABS sensors.
For Stratford Shark
NOTE if your hatch release is not working,
first thing to do is push in the door pin switch and let it snap out, this should establish the ground,
THEN the hatch pull will operate if it has a good fuse
Thread Starter
Track Day
Joined: Jul 2024
Posts: 24
Likes: 3
From: Northern NV
For some reason I have wondered if the hatch release has something to do with the digital dash. My electric hatch release is a different problem in itself. Motor runs, but jams up before the hatch release works. I will check to see if it runs, but how does the hatch affect the dash? I have had the hatch open to recharge the battery after sitting in the cold.
Mrmerlin - I did check every fuse with a meter. I can go through them again. Do you happen to know which wire sends power and which is ground to the digital dash? If I knew that I could trace the wire back. The wiring diagram on this will take me some hours to find the source.
Mrmerlin - I did check every fuse with a meter. I can go through them again. Do you happen to know which wire sends power and which is ground to the digital dash? If I knew that I could trace the wire back. The wiring diagram on this will take me some hours to find the source.
Thread Starter
Track Day
Joined: Jul 2024
Posts: 24
Likes: 3
From: Northern NV
I played with the fuses some more, pulling them in and out, then I pushed on the long vertical wire connectors in the middle and the digital parts lit up, but nothing showing. Gas gauge, tach, and speedometer still don't work, but I am making progress. Does anyone know which vertical connector(s) control the dash? I am thinking that cold weather and/or lifting the car up and down on the lift which could make some slight body twists might have caused a shift in the connectors. I'm sure they need cleaning. Last time I had the car on the lift the driver side door light button stopped functioning. I pulled on the hatch motor switch, but it just kept spinning and wouldn't shut off. I held it still, and hooked it back up to the arm and that stopped it. The motor just jams up and turns off if it is hooked up to the hatch release arm and won't release. Adjusting motor position up or down doesn't help. Seems like there should be some reset relay that makes it just go one turn. My 944 would just turn once when activated. I can live without a trunk release, but not without a gas gauge or speedometer. *UPDATE* - I went in the garage today to turn the heater off, opened the car door, turned the key, and dash was working fine again! The lift was completely lowered at that point and I had let it sit in a relatively warm garage for a few hours. Did the old electronics thaw out or was it the lift? Who knows, but I took it for a test drive and everything is fine again...well except for that trunk release motor.
Last edited by Johnsrestos; Dec 10, 2024 at 08:46 PM. Reason: update
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Drifting
Joined: Sep 2006
Posts: 3,379
Likes: 128
From: Stratford-upon-Avon
For some reason I have wondered if the hatch release has something to do with the digital dash. My electric hatch release is a different problem in itself. Motor runs, but jams up before the hatch release works. I will check to see if it runs, but how does the hatch affect the dash? I have had the hatch open to recharge the battery after sitting in the cold.
Mrmerlin - I did check every fuse with a meter. I can go through them again. Do you happen to know which wire sends power and which is ground to the digital dash? If I knew that I could trace the wire back. The wiring diagram on this will take me some hours to find the source.
Mrmerlin - I did check every fuse with a meter. I can go through them again. Do you happen to know which wire sends power and which is ground to the digital dash? If I knew that I could trace the wire back. The wiring diagram on this will take me some hours to find the source.
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Thread Starter
Track Day
Joined: Jul 2024
Posts: 24
Likes: 3
From: Northern NV
What is supposed to make the motor stop? It should just do one rotation and stop, but mine will keep running until I put pressure on it. I have a brand new latch and one arm which goes up and down to release attaches to the motor crank with a clip to hold it on. The arm is at a slight angle since the motor crank doesn't stick out very far. There are two adjusting bolts to hold the motor. No matter how I adjust those it will jam up. If I loosen them, the motor will go up and down and it will just keep running. If the crank had shorter travel and had a longer pin plus a relay to stop the motor after one revolution it would work. I wish I could see an up close video of a working hatch motor assembly in action.
Drifting
Joined: Sep 2006
Posts: 3,379
Likes: 128
From: Stratford-upon-Avon
The motor stops because of a break in the rotary track that cuts power to the motor, and there’s a braking effect from a transistor to make sure it stops before the contact reaches the conductive track.
Team Owner
Joined: May 2004
Posts: 31,228
Likes: 4,215
From: Philly PA
NOTE the stop cycle works because the 1 amp fuse is good.
check the fuse.
If your 1 amp is good then the transistor has failed in the motor ,
their are a few writeups on how to swap them out to restore function
check the fuse.
If your 1 amp is good then the transistor has failed in the motor ,
their are a few writeups on how to swap them out to restore function