Gauge Cluster Flashing On and Off

[Seadweller]

Car is a 1998 Boxster Tiptronic with less than 40K miles.  Always garaged and covered, and never in the rain.  I took her out for some exercise weekend before last, and out of the blue, all the lights on the gauge cluster started turning off and on, almost like it was on a blinker relay.  Also, the gauges all stopped working, but twitch every now and then.  See video below please:

 

 

 

What I've tried so far is the following:

1. Disconnected the battery, reconnected it, and followed the re-connection procedure.
2. Pulled fuses B1, B10 and E1. All good.
3. Pulled the instrument cluster and removed/reinstalled the plugs to make sure they were properly seated.
4. Checked the electrical operation of other components. Everything else works fine.  The top, hazards, blinkers, lights, windows, etc.
5. Replaced the ignition switch, hoping for the best, but that didn't fix the issue.  It's the later model ignition assembly, which was replaced in 2011.
 

At this point, I'm out of options and don't know where to look next.  Is there a relay in the circuit that could be the issue?  Everything else seems sound electrically.  I have no issues starting the car, or operating any of the electrical items.  The blinking gauge cluster seems isolated from the rest of the car.

 

Any direction would be immensely appreciated!!!

[Seadweller]

Update:  I don't know if this helps, but the fuel gauge responds to the on/off routine, however there's nothing from the speedo and tach.

[Loren]

 

Check your battery and charging voltage. Battery (switch off) should be over 12 volts. Battery with the engine running should be over 13 volts.

[Seadweller]

Thanks for the kind welcome!  The battery is under a year old, but I know that doesn't dismiss it as a possible source of the issue.  I have it on a battery tender now and will check it in the morning.  The car started without issue, but I would assume a voltage lower than 12V might cause electrical circuits to malfunction.

 

I'll report back!

[Loren]

Well, the alternator or the regulator (inside the alternator) can go at any time. So please check your charging voltage.

[Seadweller]

Ok, here's an update:

 

1.  Battery voltage with the car off is 12.6V

2.  Battery voltage with the car running is 14.1V

3.  If I remove only the B1 fuse with the car running, the gauge cluster goes dark and quiet

4.  If I remove only the B10 fuse, the gauges stop working/twitching, all the indicator lights go out, and only the 3 lower screens remain lit with mileage, digital speedo, and clock, and the door chime works as well.  No flashing indicator lights.

 

The flashing lights and twitching gauges seem to be related to the B1 fuse circuit.  Thoughts?

 

Thanks!

[Loren]

Has the instrument cluster been removed recently (or ever)?

[Seadweller]

2 hours ago, Loren said:

Has the instrument cluster been removed recently (or ever)?

 

I removed it last week after it started flashing, as it was recommended that I remove and reinstall the connectors on the back to make sure there were no connector issues.  Prior to that, I don't believe it's ever been removed.  I still have it removed, but connected, sitting on a towel on the dash.

 

I've owned the car for 3 years now, and other than a new battery around 1 year ago, and routine maintenance, everything on the car has worked as designed.

Edited August 15, 2018 by Seadweller

[Loren]

Are you sure you got all the cluster connector back op and locked in place?

If so, then start looking for a poor ground (to chassis) under the dash. You can test with an ohm meter.

 

[Seadweller]

2 minutes ago, Loren said:

Are you sure you got all the cluster connector back op and locked in place?

If so, then start looking for a poor ground (to chassis) under the dash. You can test with an ohm meter.

 

 

Well, I'd say I'm 99.99% sure!  ?  I took them off twice, and reinstalled them to be sure.  One thing I need to recheck, is when I lifted the cluster to see the face of it, I believe the on/off flashing changed its cycle.  I'm going to check that again this evening.

 

Is it possible that the cluster itself has some sort of fault, or is that something that's uncommon?

 

Thanks a bunch, I GREATLY appreciate the assistance!!

[Loren]

Usually only a portion of the cluster stops working - and usually related to one of the cables. Either broken wires or bad connection/bent pins, etc.

Or a section of the back-lighting goes out.

 

Do you have access to s Porsche specific scanner like Durametric?

If so, you can run cluster diagnostics and see what it comes up with.

 

[Seadweller]

Understood.  I'll check wiring, and also I'm going to see if I have steady voltage at the B1 fuse.  Someone also mentioned checking voltage at the connector, and provided the pin locations for ground and 12V.  I guess if I can validate steady 12V+ at the connector, that would point to the cluster itself.  I don't have a Durametric, and wouldn't know how to use one unfortunately.

 

Thanks again for the help!

[wizard]

Do your side mirrors and Tiptronic work normally?

Did you by any chance refuel the car just prior to this incident?

[Seadweller]

3 hours ago, wizard said:

Do your side mirrors and Tiptronic work normally?

Did you by any chance refuel the car just prior to this incident?

 

Yes, side mirrors work fine.  I was able to drive the car home without issue with the gauge cluster going on and off.  I didn't try manual/tip operation, as I was more focused on getting home than troubleshooting.

 

I did measure voltage at the B1 fuse, and it was a steady 9.2V.  I assume that should be 12V?  If so, what would cause low voltage at the fuse box?

Edited August 16, 2018 by Seadweller

[wizard]

I yield to an electrical expert on that ... which I am most definitely not.

Fuel sender wiring issues have been known to cause cluster 'abnormalities'.

 

Edited August 16, 2018 by wizard

[Seadweller]

OK, I did a bit more experimentation at the fuse box.

 

With the ignition on, I get 9.7V at the B1 fuse.  With the engine running, the voltage at B1 is 10.8V.  If I remove the B10 fuse, the voltage at B1 goes up to 11.8V.  Voltage at the B10 fuse is 13.7V.

[Seadweller]

Spot checked a couple more fuses in row B, and all are 12.3V with the ignition on, except B1, which is 9.7V.  Something is causing a voltage drop on that specific fuse location.

[Loren]

I would suspect a badly worn ignition switch.

[Seadweller]

Just now, Loren said:

I would suspect a badly worn ignition switch.

 

I just replaced the ignition switch with a new one on Monday...That was my first thought...  ?

[Loren]

No change after that?

[Seadweller]

6 minutes ago, Loren said:

No change after that?

 

Nothing...Same exact symptoms...I don't know if this will help or not, but this is the voltage I'm getting at the B1 fuse location:

 

Ignition off - 11.2V

Ignition on - 9.7V

Engine on - 10.7V

 

Something is affecting voltage at that fuse location.  Other fuse locations have  12.3V.  Is there a relay anywhere that could be causing this?  I'm completely stumped.

[Loren]

What happens if you switch the headlights on?

or wiggle the switch?

[Seadweller]

Nothing changes.  Same voltage at B1, and all functions of the headlight switch work normally.

Edited August 16, 2018 by Seadweller

[Seadweller]

Is it possible that a poor connection at the back of the fuse panel is the culprit?

[Loren]

28 minutes ago, Seadweller said:

Is it possible that a poor connection at the back of the fuse panel is the culprit?

 

I have not seen that but I guess it could be.